    [House Hearing, 110 Congress]
    [From the U.S. Government Publishing Office]

                       NEAR-EARTH OBJECTS (NEOS)--STATUS
                        OF THE SURVEY PROGRAM AND REVIEW
                       OF NASA'S 2007 REPORT TO CONGRESS

    =======================================================================

                                    HEARING

                                   BEFORE THE

                     SUBCOMMITTEE ON SPACE AND AERONAUTICS

                      COMMITTEE ON SCIENCE AND TECHNOLOGY
                            HOUSE OF REPRESENTATIVES

                           ONE HUNDRED TENTH CONGRESS

                                 FIRST SESSION

                                   __________

                                NOVEMBER 8, 2007

                                   __________

                               Serial No. 110-72

                                   __________

         Printed for the use of the Committee on Science and Technology

         Available via the World Wide Web: http://www.house.gov/science

                                     ______

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                      COMMITTEE ON SCIENCE AND TECHNOLOGY

                     HON. BART GORDON, Tennessee, Chairman
    JERRY F. COSTELLO, Illinois          RALPH M. HALL, Texas
    EDDIE BERNICE JOHNSON, Texas         F. JAMES SENSENBRENNER JR.,
    LYNN C. WOOLSEY, California              Wisconsin
    MARK UDALL, Colorado                 LAMAR S. SMITH, Texas
    DAVID WU, Oregon                     DANA ROHRABACHER, California
    BRIAN BAIRD, Washington              ROSCOE G. BARTLETT, Maryland
    BRAD MILLER, North Carolina          VERNON J. EHLERS, Michigan
    DANIEL LIPINSKI, Illinois            FRANK D. LUCAS, Oklahoma
    NICK LAMPSON, Texas                  JUDY BIGGERT, Illinois
    GABRIELLE GIFFORDS, Arizona          W. TODD AKIN, Missouri
    JERRY MCNERNEY, California           JO BONNER, Alabama
    LAURA RICHARDSON, California         TOM FEENEY, Florida
    PAUL KANJORSKI, Pennsylvania         RANDY NEUGEBAUER, Texas
    DARLENE HOOLEY, Oregon               BOB INGLIS, South Carolina
    STEVEN R. ROTHMAN, New Jersey        DAVID G. REICHERT, Washington
    JIM MATHESON, Utah                   MICHAEL T. MCCAUL, Texas
    MIKE ROSS, Arkansas                  MARIO DIAZ-BALART, Florida
    BEN CHANDLER, Kentucky               PHIL GINGREY, Georgia
    RUSS CARNAHAN, Missouri              BRIAN P. BILBRAY, California
    CHARLIE MELANCON, Louisiana          ADRIAN SMITH, Nebraska
    BARON P. HILL, Indiana               PAUL C. BROUN, Georgia
    HARRY E. MITCHELL, Arizona
    CHARLES A. WILSON, Ohio
                                     ------

                     Subcommittee on Space and Aeronautics

                      HON. MARK UDALL, Colorado, Chairman
    DAVID WU, Oregon                     TOM FEENEY, Florida
    NICK LAMPSON, Texas                  DANA ROHRABACHER, California
    STEVEN R. ROTHMAN, New Jersey        FRANK D. LUCAS, Oklahoma
    MIKE ROSS, Arizona                   JO BONNER, Alabama
    BEN CHANDLER, Kentucky               MICHAEL T. MCCAUL, Texas
    CHARLIE MELANCON, Louisiana
    BART GORDON, Tennessee               RALPH M. HALL, Texas
                  RICHARD OBERMANN Subcommittee Staff Director
                PAM WHITNEY Democratic Professional Staff Member
                KEN MONROE Republican Professional Staff Member
                ED FEDDEMAN Republican Professional Staff Member
                        DEVIN BRYANT Research Assistant

                                C O N T E N T S

                                November 8, 2007

                                                                       Page
    Witness List.....................................................     2

    Hearing Charter..................................................     3

                               Opening Statements

    Statement by Representative Mark Udall, Chairman, Subcommittee on
      Space and Aeronautics, Committee on Science and Technology,
      U.S. House of Representatives..................................    11
        Written Statement............................................    12

    Statement by Representative Tom Feeney, Ranking Minority Member,
      Subcommittee on Space and Aeronautics, Committee on Science and
      Technology, U.S. House of Representatives......................    13
        Written Statement............................................    15

                                    Panel 1:

    Representative Luis Fortuno, Resident Commissioner, Puerto Rico
        Oral Statement...............................................    16
        Written Statement............................................    17

    Discussion
      Impact of Shutting Down Arecibo................................    18
      George Brown...................................................    19
      Importance of Arecibo With Regard to Cost......................    20
      Visiting Arecibo...............................................    21

                                    Panel 2:

    Dr. James L. Green, Director, Planetary Science Division, Science
      Mission Directorate, National Aeronautics and Space
      Administration (NASA)
        Oral Statement...............................................    22
        Written Statement............................................    24
        Biography....................................................    27

    Dr. Scott Pace, Associate Administrator, Program Analysis and
      Evaluation, National Aeronautics and Space Administration
      (NASA)
        Oral Statement...............................................    28
        Written Statement............................................    30
        Biography....................................................    34

    Dr. Donald K. Yeomans, Manager, Near-Earth Object Program Office,
      Jet Propulsion Laboratory
        Oral Statement...............................................    34
        Written Statement............................................    37
        Biography....................................................    40

    Dr. Donald B. Campbell, Professor of Astronomy, Cornell
      University; Former Director, Arecibo Observatory
        Oral Statement...............................................    40
        Written Statement............................................    42

    Dr. J. Anthony Tyson, Professor of Physics, University of
      California, Davis; Director, Large Synoptic Survey Telescope
      Project
        Oral Statement...............................................    47
        Written Statement............................................    48
        Biography....................................................    54

    Mr. Russell ``Rusty'' L. Schweickart, Chairman and Founder, B612
      Foundation
        Oral Statement...............................................    54
        Written Statement............................................    57
        Biography....................................................    94

    Discussion
      Importance of Surveying Objects Larger Than 140m...............    95
      Risk of Changing the Project Timeline..........................    95
      Non-U.S. NEO Characterization..................................    96
      Increasing International NEO Collaboration.....................    96
      Public Safety..................................................    97
      NEO Deflection Technology......................................    98
      Deflection of NEOs into Keyholes...............................    99
      More on International Collaboration............................   100
      Probability of a 10km NEO Hitting Earth in the Near Future.....   100
      Apophis NEO....................................................   101
      Understanding the Threat Posed By NEOs.........................   101
      Future Responsibility..........................................   102
      Potential NASA Partnerships....................................   103
      NASA Funding NEO Partnerships..................................   103
      Using LSST for NEO Detection...................................   105
      Radar Versus Optical NEO Detection.............................   106
      Importance of Arecibo Radar....................................   106
      Radius of NEO Surveys..........................................   106
      Ramifications of an Asteroid Hitting Earth.....................   107
      NEO Survey Objectives..........................................   109
      Planetary Defense Responsibilities.............................   109
      Goldstone Antenna Upgrades.....................................   111
      Future Steps in NEO Detection and Deflection...................   112
      Orbital Determination..........................................   112
      More on Detection and Deflection...............................   113
      Importance of NEO Characterization.............................   114

                 Appendix 1: Answers to Post-Hearing Questions

    Dr. James L. Green, Director, Planetary Science Division, Science
      Mission Directorate, National Aeronautics and Space
      Administration (NASA)..........................................   118

    Dr. Scott Pace, Associate Administrator, Program Analysis and
      Evaluation, National Aeronautics and Space Administration
      (NASA).........................................................   127

    Dr. Donald K. Yeomans, Manager, Near-Earth Object Program Office,
      Jet Propulsion Laboratory......................................   134

    Dr. Donald B. Campbell, Professor of Astronomy, Cornell
      University; Former Director, Arecibo Observatory...............   142

    Dr. J. Anthony Tyson, Professor of Physics, University of
      California, Davis; Director, Large Synoptic Survey Telescope
      Project........................................................   146

    Mr. Russell ``Rusty'' L. Schweickart, Chairman and Founder, B612
      Foundation.....................................................   151

                 Appendix 2: Additional Material for the Record

    NASA Rebuttal to remarks made by Mr. Schweickart during the
      November 8, 2007 hearing regarding Near-Earth Objects..........   162

    Statement of The Planetary Society in Support of Planetary Radar
      at the Arecibo Observatory.....................................   163

    Letter to The Honorable Dana Rohrabacher from John W. Meredith,
      President, IEEE-USA, dated 08 November 2007....................   164

     NEAR-EARTH OBJECTS (NEOS)--STATUS OF THE SURVEY PROGRAM AND REVIEW OF
                         NASA'S 2007 REPORT TO CONGRESS

                                  ----------

                           THURSDAY, NOVEMBER 8, 2007

                      House of Representatives,
                 Subcommittee on Space and Aeronautics,
                           Committee on Science and Technology,
                                                        Washington, DC.

        The Subcommittee met, pursuant to call, at 10:07 a.m., in
    Room 2318 of the Rayburn House Office Building, Hon. Mark Udall
    [Chairman of the Subcommittee] presiding.

                                hearing charter

                     SUBCOMMITTEE ON SPACE AND AERONAUTICS

                      COMMITTEE ON SCIENCE AND TECHNOLOGY

                         U.S. HOUSE OF REPRESENTATIVES

                       Near-Earth Objects (NEOs)--Status

                        of the Survey Program and Review

                       of NASA's 2007 Report to Congress

                           thursday, november 8, 2007
                             10:00 a.m.-12:00 p.m.
                       2318 rayburn house office building

    Purpose

        On Thursday, November 8, 2007 at 10:00 a.m., the House Committee on
    Science and Technology's Subcommittee on Space and Aeronautics will
    hold a hearing to examine the status of NASA's Near-Earth Object survey
    program, review the findings and recommendations of NASA's report to
    Congress, Near-Earth Object Survey and Deflection Analysis of
    Alternatives, and to assess NASA's plans for complying with the
    requirements of Section 321 of the NASA Authorization Act of 2005.

    Witnesses

    Panel 1

              The Honorable Luis G. Fortuno, Resident Commissioner,
            Puerto Rico

    Panel 2

              Dr. James Green, Science Mission Directorate, NASA

              Dr. Scott Pace, Program Analysis and Evaluation, NASA

              Dr. Donald K. Yeomans, Jet Propulsion Laboratory

              Dr. Donald B. Campbell, Cornell University

              Dr. J. Anthony Tyson, University of California, Davis

              Mr. Russell ``Rusty'' Schweickart, B612 Foundation

    Potential Issues

              What is the current status of NASA's Near-Earth
            Object (NEO) search program, and how urgent is the need to move
            ahead with the expanded search that was directed in the 2005
            NASA Authorization Act? Is the timeline for achieving the goal
            appropriate or would changes in the ``deadline'' provide
            benefits in terms of technical approaches or costs?

              What are the most important priorities to address
            relative to detecting, characterizing, and developing the means
            to deflect NEOs?

              NASA submitted a 2007 report to Congress on NEO
            search and deflection options, but the report doesn't provide a
            recommended option, as required in the 2005 NASA Authorization
            Act. What approach does NASA recommend for complying with the
            legislated mandate and what steps has NASA taken to begin
            implementing any of the options identified in the report?

              NASA's report to Congress mentions search options
            that would rely on planned ground-based telescopes that have
            been proposed for development under the auspices of other
            agencies. What role, if any, should NASA play in supporting the
            NEO-related operations of those telescopes? What alternatives
            exist if those assets are not funded and developed?

              Planetary radar facilities have been cited as
            critical for providing more precise orbital determinations of
            potentially hazardous NEOs. However, the two radar facilities
            currently being used to obtain data on NEOs [Arecibo and
            Goldstone] may not be available in the future. What are the
            implications should existing planetary radar facilities become
            unavailable?

              A NEO object, Apophis, has been identified and could
            pass as close as 23,100 kilometers from the Earth's surface in
            2029 and return again for a close approach in 2036. What threat
            does this object pose in terms of a potential impact with
            Earth, and what is needed to improve our understanding of the
            threat?

              How much time would be required to prepare a
            mitigation approach if a hazardous object were discovered to be
            on a collision course with Earth? How much time would likely be
            available?

              How well understood are the potential approaches to
            deflecting asteroids? What is the confidence level in the
            technologies that would be required? What information is needed
            to assess the various approaches, and how will decisions be
            made on which mitigation strategy to take?

              What is the degree of international involvement in
            searching for, characterizing, and studying deflection options
            for NEOs? What steps, if any, has NASA taken on potential
            collaboration or coordination of NEO-related initiatives?

              How will policy and legal issues involved in
            addressing NEOs--e.g., when and how to warn the public and
            whether to use nuclear explosives to deflect an asteroid--be
            handled on national and international levels? What steps have
            NASA and other federal agencies taken to date to address such
            issues?

    Background

        Astronomers estimate that millions of asteroids, comets,
    meteoroids, and other cosmic debris orbit within the vicinity of Earth
    and the Sun. The Earth is continually bombarded by these remnants from
    the formation of the solar system. Small objects ranging from the size
    of a dust particle up to a size of about 50 meters in diameter do not
    pose impact threats to Earth, because they burn up and disintegrate
    upon entry to the Earth's atmosphere. However, larger objects pose
    potentially catastrophic threats because they would not disintegrate
    before impacting the Earth. Near-Earth Objects (NEOs) are defined as
    asteroids and comets whose trajectories bring them within 45 million
    kilometers (km) of the Earth. NEOs larger than about 140 meters, whose
    orbits about the Sun bring them within 7.5 million km of the Earth's
    orbit, are classified as potentially hazardous objects (PHOs). Most of
    these objects are asteroids. According to NASA, there are currently 900
    known Potentially Hazardous Asteroids (PHAs). NASA scientists estimate
    that the population of PHOs is about 20,000 objects.
        The literature on NEOs is not entirely consistent on the threats
    posed by various sizes of objects. Information from NASA's Near-Earth
    Object Program webpage [http://neo.jpl.nasa.gov] and other sources
    indicates the following:

              Objects larger than 50 meters can survive entry
            through the Earth's atmosphere, and could cause local disasters
            or events such as tsunamis upon impact. Estimates of the
            frequency of impacts of objects of this size range from once
            every 100 years to once every 500 years.

              Objects larger than one km in diameter that impact
            Earth would cause disasters on a global scale, and ``the impact
            debris would spread throughout the Earth's atmosphere so that
            plant life would suffer from acid rain, partial blocking of
            sunlight, and from the firestorms resulting from heated impact
            debris raining back down upon the Earth's surface.'' Estimates
            of the frequency of these range from once every few hundred
            thousand years to once every million years.

              ``Extinction-class'' objects (10 km or greater in
            size) are estimated to occur on average once every 50 million
            to 100 million years.

    Past NEO Impacts and Events
        Evidence from past major NEO impacts or aerial explosions
    illustrates the catastrophic consequences that these objects can have:

              The impact of a NEO on the north side of Mexico's
            Yucatan Peninsula some 65,000,000 years ago that is thought to
            have helped bring about the extinction of the dinosaurs and to
            have destroyed 75 percent of life on Earth. Scientists estimate
            the frequency of an impact event of this magnitude to be about
            once every 50-100 million years.

              The Barringer Meteor Crater in Arizona is about one
            kilometer wide and is estimated to be 50,000 years old. The
            impact was caused by a nickel-iron meteorite, weighing about
            300,000 tons and whose size was roughly 45 meters in diameter.
            The impact explosion was comparable to 20 million tons of TNT
            and created a hole 174 meters deep. Scientists estimate these
            types of impacts to occur once every 250-1,000 years.

              The Tunguska Event took place in Siberia in 1908 when
            a NEO estimated to be 50-100 meters in size disintegrated about
            five-ten kilometers above the Earth's surface. That event
            unleashed energy comparable to an estimated 10-15 million tons
            of TNT. The explosion flattened trees and other vegetation over
            an area of roughly 2,000 square kilometers [about 500,000
            acres]. Scientists estimate that this scale of impact would
            occur about once every 250-1,000 years.

        Within the last two decades, instances of objects that passed near
    Earth brought increasing interest in identifying NEOs and exploring
    options to protect Earth from a potential NEO impact. For example:

              On March 23, 1989, the 1989 FC asteroid with an
            estimated diameter of 0.3 miles came within 430,000 miles of
            Earth. 1989 FC carried the energy estimated to be more than
            1,000 one-megaton hydrogen bombs. The asteroid was only
            discovered after it had made its closest approach to Earth.

              Asteroid 99942 Apophis, discovered in 2004, is
            estimated to be roughly 300 meters in diameter, and could pass
            as close as 29,470 km [about 18,300 miles] from the Earth's
            surface [i.e., about the altitude that geosynchronous
            communications satellites orbit the Earth] in 2029. Radar
            observations conducted at the Arecibo Observatory in January
            2005 significantly improved the understanding of the asteroid's
            orbit. The probability of impact in 2036, when the asteroid
            makes another close approach, is currently estimated to be 1/
            45,000. Scientists hope to use Arecibo again in 2012 to further
            refine the orbital coordinates when the asteroid is expected to
            be in a favorable viewing position.

        Determining the population of NEOs, including those in the PHO
    category, can only be achieved by conducting a search campaign using
    ground-based or space-based telescopes, or a combination of the two.

    Previous Congressional Actions Related to NEOs
        Congress has taken a number of steps since 1990 to promote
    increased understanding of NEOs and the potential threat they pose, as
    well as potential options for protecting Earth from hazardous NEOs. The
    National Aeronautics and Space Administration Multi-year Authorization
    Act of 1990 directed NASA to conduct two workshop studies on NEO
    detection and interception. In 1993 the House Science and Technology
    Committee held a hearing to review the results of the two reports, and
    in 1994 [by means of House Report 103-654, which accompanied the
    National Aeronautics and Space Administration Authorization and Space
    Policy Act for Fiscal Year 1995] gave further direction to NASA to
    coordinate with the Department of Defense and international space
    partners on identifying and cataloging NEOs greater than one kilometer
    in diameter that are in an orbit around the Sun that crosses Earth's
    orbit within the next decade. In 1998, NASA established a Near-Earth
    Object Program Office at the Jet Propulsion Laboratory and established
    its Spaceguard Survey. The Survey had the goal of detecting and
    cataloging 90 percent of NEOs one km or larger by the end of 2008.

    NASA's Current NEO Survey Program and Budget
        The Spaceguard Survey was housed in NASA's Exploration Systems
    Mission Directorate in recent years, but earlier this year it was moved
    to the Science Mission Directorate. NASA's report to Congress states
    that the current budget for the program is $4.1 million per year for
    Fiscal Years 2006-2012. NASA officials report that the annual budget is
    allocated as follows: $3 million are used to support the search teams
    and ground-based telescope facilities, $500,000 is allocated to JPL for
    studies on near-Earth objects, $400,000 is provided to the Minor
    Planets Center at the Smithsonian Center for Astrophysics to refine the
    orbital coordinates of NEOs that have been detected, and the remainder
    is allocated to additional NASA-funded studies.
        NASA's report to Congress states that as of December 2006 the
    Spaceguard Survey had identified 701 of the estimated 1100 NEOs larger
    than one km that are believed to exist.

    Recent Congressional Action on NEOs
        Section 321 of the 2005 NASA Authorization Act directed NASA ``to
    plan, develop, and implement a Near-Earth Object Survey program to
    detect, track, catalogue, and characterize the physical characteristics
    of near-Earth objects equal to or greater than 140 meters in diameter
    in order to assess the threat of such near-Earth objects to the Earth.
    It shall be the goal of the Survey program to achieve 90 percent
    completion. . .within 15 years after the date of enactment of this
    Act.'' Section 321 also directed NASA to report to Congress on an
    analysis of ground-based and space-based alternatives to conduct the
    Survey; a recommendation on which Survey option to pursue and a
    proposed budget; and an analysis of options to divert an object that
    threatens impact with Earth.

    NASA's Near-Earth Object Survey and Deflection Analysis of Alternatives
            Report to Congress
        NASA's report, Near-Earth Object Survey and Deflection Analysis of
    Alternatives, Report to Congress, prepared in response to Sec. 321 of
    the NASA Authorization Act of 2005, was submitted to Congress in March
    2007. The study was led and managed by NASA's Office of Program
    Analysis and Evaluation. The report is a condensed version of a longer,
    un-circulated version that included the analysis on which findings of
    the report to Congress were based. The 2007 report to Congress provides
    options for meeting the Survey goals by 2020, as required in the Act,
    and options for meeting the goals on a longer timeframe. However, the
    report does not provide Congress with NASA's recommended option for
    conducting the Survey or provide a cost estimate for that Survey.
        The report's basic conclusion is that ``NASA recommends that the
    program continue as currently planned, and we will also take advantage
    of opportunities using potential dual-use telescopes and spacecraft--
    and partner with other agencies as feasible--to attempt to achieve the
    legislated goal within 15 years. However, due to current budget
    constraints, NASA cannot initiate a new program at this time.''
        In addition, the report contained a number of additional findings,
    including:

              ``The goal of the Survey Program should be modified
            to detect, track, catalogue, and characterize, by the end of
            2020, 90 percent of all Potentially Hazardous Objects (PHOs)
            greater than 140m whose orbits pass within 0.05 AU of the
            Earth's orbit (as opposed to surveying for all NEOs).

              The Agency could achieve the specified goal of
            surveying for 90 percent of the potentially hazardous NEOs by
            the end of 2020 by partnering with other government agencies on
            potential future optical ground-based observatories and
            building a dedicated NEO survey asset assuming the partners'
            potential ground assets come online by 2010 and 2014, and a
            dedicated asset by 2015.

              Together, the two observatories potentially to be
            developed by other government agencies could complete 83
            percent of the survey by 2020 if observing time at these
            observatories is shared with NASA's NEO Survey Program.

              New space-based infrared systems, combined with
            ground-based assets, could reduce the overall time to reach the
            90 percent goal by at least three years. Space systems have
            additional benefits as well as costs and risks compared to
            ground-based alternatives.

              Radar systems cannot contribute to the search for
            potentially hazardous objects, but may be used to rapidly
            refine tracking and to determine object sizes for a few NEOs of
            potentially high interest. Existing radar systems are currently
            oversubscribed by other missions.

              Determining a NEO's mass and orbit is required to
            determine whether it represents a potential threat and to
            provide required information for most alternatives to mitigate
            such a threat. Beyond these parameters, characterization
            requirements and capabilities are tied directly to the
            mitigation strategy selected.''

        The NASA report also describes the general advantages and
    disadvantages of using ground versus space-based search systems and
    analyzes an approach that includes a combination of ground-based and
    space-based NEO search capabilities:

              Ground-based Optical Systems. Ground-based telescopes
            are relatively easy to maintain and offer the flexibility for
            upgrades. They are limited by their nighttime or early morning
            viewing periods as well as the atmosphere's effects on
            observations.

              Space-Based Optical Systems. These systems can take
            advantage of proven space technologies, are not restricted in
            viewing hours and atmospheric interference, and can observe
            objects in inner Earth orbits or orbits similar to Earth's more
            easily than can ground-based systems. Space-based survey
            approaches however require access to space, data downlinks, and
            replacement spacecraft.

              Space-Based Infrared Systems. The technology for
            space-based infrared systems is less mature than space-based
            optical technology, however the infrared systems would require
            smaller aperture telescopes and could provide greater accuracy
            on the sizes of NEOs they detect.

        The NASA report suggests that the goals of the Congressionally-
    mandated survey could be met by acquiring shared access to a proposed
    ground-based NSF/DOE, telescope system, the Large Synoptic Survey
    Telescope (LSST) and a potential Air Force telescope system, the
    Panoramic Survey Telescope and Rapid Response System (Pan-STARRS). In
    addition, this exemplar search program would require an additional
    LSST-type telescope dedicated to the NEO survey effort.
        LSST is proposed as a large-aperture, wide-field telescope.
    According to literature from the LSST project, the telescope will
    ``Conduct a survey over an enormous volume of sky; do it with a
    frequency that enables repeat exposures of every part of the sky every
    few nights in multiple colors; and continue this mode for ten years to
    achieve astronomical catalogs thousands of times larger than have ever
    previously been compiled.'' LSST was recommended as a high priority
    initiative in the 2001 National Academies Astronomy and Astrophysics
    Decadal Survey. In addition, the 2003 National Academies Solar System
    Exploration Survey included the following recommendation: ``The SSE
    [Solar System Exploration] Survey recommends that NASA partner equally
    with the National Science Foundation to design, build, and operate a
    survey facility, such as the Large Synoptic Survey Telescope (LSST). .
    .to ensure that LSST's prime solar system objectives are accomplished''
    LSST has not yet been approved as new project start by the National
    Science Foundation.
        The Director of the LSST project is expected to testify that LSST
    could complete the mandated survey within 12 years from the start of
    the telescope operations. This goal would involve modifications to the
    observing strategy and to the data processing procedures. The LSST
    project estimates that the cost of an LSST NEO survey over 12 years
    would be about $125M.
        Pan-STARRS is being developed by the University of Hawaii with
    funding from the U.S. Air Force. A main goal of Pan-STARRS is to detect
    potentially hazardous objects. Pan-STARRS is planned to be a system of
    four individual telescopes that will survey large areas of the sky at a
    high degree of sensitivity. The prototype one-mirror Pan-STARRS
    telescope is complete; a full four-telescope system has not yet been
    approved.
        The NASA report to Congress also indicates that by using a space-
    based infrared telescope [along with the LSST and Pan-STARRS systems],
    NASA could exceed the mandated requirement and detect an estimated 90
    percent of the PHO population by 2017.
        An additional capability that could be brought to bear on the NEO
    survey task is NASA's Wide-field Infrared Survey Explorer (WISE), which
    is scheduled for launch in 2009. The WISE spacecraft will survey the
    sky in the infrared band at high sensitivity. Asteroids, which absorb
    solar radiation, can be observed through the infrared band. NASA
    officials told Committee staff that NASA plans to use WISE to detect
    NEOs, in addition to performing its science goals. NASA expects that
    WISE could detect 400 NEOs [or roughly two percent of the estimated NEO
    population of interest] within the spacecraft's six month--one year
    mission.
        It should be noted that the National Academies' 2001 report New
    Frontiers in the Solar System [the solar system exploration decadal
    survey] commented on the potential value of ground-based observatories
    for detecting near-Earth objects: ``The SSE Survey's Primitive Bodies
    Panel endorses the concept of a large telescope capable of an all-sky
    search strategy that would reveal large numbers of near-Earth
    objectsalso endorses a telescope that would enable the physical study
    of such objects by spectroscopic and photometric techniques. The panel
    heard recommendations for the Large Synoptic Survey Telescope (LSST)
    and the Next Generation Lowell Telescope (NGLT). . .Other options,
    including the Panoramic Optical Imager concept, should be explored and
    a choice made that NASA can support in the next decade.
        According to the NASA report to Congress, once a NEO is identified,
    further characterization of its mass and orbit are required to ``assess
    the threat'' as required in the Act. Characterization involves
    observations that provide details on an object's structure, whether it
    is a single or binary NEO, its porosity, rotation rate, composition,
    and surface features. NASA's report to Congress discusses the need to
    characterize an object to inform decisions on mitigation.
        According to NASA officials, characterization is usually focused on
    those objects that are identified as posing a potential threat. Both
    optical and radar ground-based systems can be used, however radar
    provides precise orbital determinations more quickly than optical
    systems. A dedicated in-situ mission to observe the object would
    provide the greatest detail on the character of the object and,
    according to the NASA report to Congress, help to ``confirm the
    probability of impact and characterize the potential threat if
    deflection is necessary.''
        The report presents two broad strategies for diverting asteroids
    from a collision path with Earth. ``Impulsive'' options would involve
    the use of conventional or nuclear explosives and have immediate
    results. ``Slow push'' options would achieve deflection results over a
    period of time.

              ``Impulsive'' options include:

                      Surface conventional explosive (detonating on
                    impact)

                      Subsurface conventional explosive

                      Standoff nuclear explosive (detonate on flyby
                    with proximity fuse)

                      Surface nuclear explosive (detonate via
                    impact with surface fuse)

                      Delayed nuclear explosive (surface lander,
                    detonate at chosen time)

                      Subsurface nuclear explosive

                      Kinetic impact (high speed impact)

              ``Slow push'' approaches include:

                      Focused solar (focused beam to burn-off
                    surface material)

                      Pulsed laser (rendezvous mission that burns-
                    off material using laser)

                      Mass driver (rendezvous mission mines and
                    ejects material)

                      Gravity tractor (large rendezvous mission
                    flies in proximity to ``pull'' object off course)

                      Asteroid tug (rendezvous mission attaches to
                    and pushes object)

                      Heating of surface material

        The report includes the following findings on deflection
    alternatives:

              ``Nuclear standoff explosions are assessed to be 10-
            100 times more effective than the non-nuclear alternatives. .
            .. Other techniques involving the surface or subsurface of
            nuclear explosions may be more efficient, but they run the risk
            of fracturing the target NEO. They also carry higher
            development and operations risks.

              Non-nuclear kinetic impactors are the most mature
            approach and could be used in some deflection/mitigation
            scenarios, especially for NEOs that consist of a single, small
            solid body.

              ``Slow push'' mitigation techniques are the most
            expensive, have the lowest level of technical readiness, and
            their ability to both travel to and divert a threatening NEO
            would be limited unless mission durations of many years to
            decades are possible.

              30-80 percent of potentially hazardous NEOs are in
            orbits that are beyond the capability of current or planned
            launch systems. Therefore, planetary gravity assist swing-by
            trajectories or on-orbit assembly of modular propulsion systems
            may be needed to augment launch vehicle performance, if these
            objects need to be deflected.''

        Critics of NASA's analysis of deflection options argue that NASA's
    report focuses on atypical asteroid threats rather than the objects of
    size ranges that have a much higher probability of actually impacting
    the Earth. They argue that NASA's focus on the less likely scenarios
    results in a set of deflection requirements that are skewed towards
    nuclear explosives. If the focus would be placed on addressing the
    deflection requirements of the smaller, more common PHOs, the critics
    of NASA's analysis would assert that ``over 99 percent of them can be
    deflected using non-nuclear means.'' One of the witnesses at the
    hearing, Mr. Russell ``Rusty'' Schweickart, will discuss issues related
    to NASA's analysis of deflection options, as well as identify what he
    believes are serious technical flaws in NASA's report to Congress.

    Planetary Radar Facilities
                Arecibo Observatory
        The Arecibo Observatory in Puerto Rico, which has been described as
    ``the largest and most sensitive'' ground-based radar telescope on
    Earth, has been used to reduce the uncertainty of NEO collision
    estimates and refine the time period of when a NEO may pass near Earth.
    In addition, radar observations are more precise than data from optical
    telescopes in identifying details on the mass, shapes, trajectories,
    sizes, and on whether the NEO is a single object or part of a binary
    system. In 2005, Arecibo observations improved the estimates of the
    trajectory for the object, Apophis, which is on a path that will take
    it close to Earth in 2029. Research using the Arecibo Observatory also
    helps improve our understanding of how solar radiation influences near-
    Earth objects.
        Arecibo is operated by Cornell University under a cooperative
    agreement with the National Science Foundation. A 2006 independent
    review of all NSF ground-based astronomy facilities recommended that
    ``The National Astronomy and Ionosphere Center [Arecibo Observatory] .
    . .should seek partners who will contribute personnel or financial
    support to the operation of Arecibo. . . by 2011 or else these
    facilities should be closed.'' At present, the planetary radar facility
    at Arecibo is funded through FY 2008. Funding beyond that date is
    uncertain.

                NASA's Goldstone Deep Space Tracking Station
        The only planetary radar facility other than Arecibo is NASA's
    Goldstone Deep Space Tracking Station in Goldstone, California.
    Goldstone is less sensitive than Arecibo, however its steerable antenna
    allows it to see a larger portion of the sky. NASA is planning to
    replace the current Deep Space Network antennas and is looking at a
    number of options, including phased array antennas. The current
    replacement options do not appear to provide a planetary radar
    capability comparable to that of the existing Goldstone facility.
        The 2003 National Academies Solar System Exploration Survey report
    contained the following recommendation: ``In addition, NASA should
    continue to support ground-based observatories for planetary science,
    including the planetary radar capabilities at the Arecibo Observatory
    in Puerto Rico and the Deep Space Network's Goldstone facility in
    California. . .as long as they continue to be critical to missions and/
    or scientifically productive. . .''

    NEO Contributions to Science, Human Exploration, and Resource
            Utilization
        The NASA report notes that an increased search for and
    characterization of NEOs will benefit scientific discovery and study of
    Kuiper Belt Objects, as well as in determining whether certain comets
    originated in the Kuiper Belt. Further data on NEOs could also provide
    information that could be used to consider extracting and using
    asteroid resources and for considering a potential human mission to an
    asteroid. A 1998 National Academies Report on The Exploration of Near-
    Earth Objects notes that:

             ``Although it would be difficult to justify human exploration
            of NEOs on the basis of cost-benefit analysis of scientific
            results alone, a strong case can be made for starting with NEOs
            if the decision to carry out human exploration beyond low Earth
            orbit is made for other reasons. Some NEOs are especially
            attractive targets for astronaut missions because of their
            orbital accessibility and short flight duration. Because they
            represent deep space exploration at an intermediate level of
            technical challenge, these missions would also serve as
            stepping stones for human missions to Mars. Human exploration
            of NEOs would provide significant advances in observational and
            sampling capabilities.''

    NEO-Related Activities at the United Nations
        The United Nation's Committee on the Peaceful Uses of Outer Space
    (COPUOS), Scientific and Technical Subcommittee has discussed and
    considered the issue of NEOs. In 2006, the subcommittee established a
    Working Group on Near-Earth Objects to focus on the issue over the
    2006-2007 timeframe and also formed an Action Team. Over the next one
    to two years, the subcommittee plans to continue to obtain reports on
    NEO activities and to address the need for more international
    coordination on observations and follow-up studies. The subcommittee
    also plans to work on international procedures for handling NEO
    threats.

    Space Science Missions to Comets and Asteroids
        In addition to its ground-based Spaceguard Survey program, NASA and
    non-U.S. space agencies have launched, or are planning to undertake a
    number of space science missions to study asteroids and comets. NASA's
    report to Congress notes that information gained from these missions
    benefits the agency's current NEO program. A number of past, current,
    and future missions of note include:

              NASA's Near-Earth Asteroid Rendezvous (NEAR) mission,
            launched in 1996, flew by two asteroids and studied one, Eros;

              The Stardust mission collected dust samples from
            comet Wild 2;

              Deep Impact, launched in 2004, penetrated comet
            Tempel 1;

              The Dawn mission, launched in late September 2007 is
            en route to study, Ceres and Vesta, two of the largest known
            asteroids located in the main asteroid belt between Mars and
            Jupiter;

              Japan's Hayabusa mission had the objective of
            collecting a sample from the near-Earth asteroid Itokawa, and
            the sample carrier is en route back to Earth; and

              The European Space Agency's Rosetta mission to comet
            Churymov-Gerasimenko in late 2014 will rendezvous with and land
            on the comet.

              In addition, the European Space Agency has conducted
            studies on a potential space mission that could test and
            validate technologies for deflecting an asteroid.
        Chairman Udall. Good morning. This hearing will come to
    order. I would like to extend a particular welcome to our
    witnesses, and in particular, recognize Congressman Luis
    Fortuno's presence here with us today.
        As many of you may recall, today's hearing on Near-Earth
    Objects was originally scheduled for October 11, but we
    postponed it in the wake of our good friend Rep. Jo Ann Davis'
    untimely death.
        Thus, before we proceed any further, I would like to
    express my appreciation to each of the witnesses for your
    willingness to accommodate that postponement, and appear before
    us today. Your testimony will be invaluable to us as we
    consider how best to proceed in getting a better understanding
    of the potential threats of Near-Earth Objects, NEOs, as well
    as options for dealing with them.
        Today's hearing is the latest in a series that stretches
    back to the early 1990s. We have come a long way since the late
    George Brown, former Chairman of the Science and Technology
    Committee, led the first efforts to focus Congressional
    attention on the potential threat posed by Near-Earth asteroids
    and comets.
        It has been a bipartisan effort over the intervening years,
    and a lot has been accomplished. In that regard, I want in
    particular to salute the dedication of Mr. Rohrabacher in
    pushing for continued federal initiatives to detect, track, and
    catalog NEOs, as well as to examine ways to deflect them if
    necessary. He has been an effective catalyst for action, and I
    look forward to continuing to work with him on this issue.
        As we will hear from our witnesses, much progress has been
    made in detecting and cataloging the largest NEOs over the last
    decade. However, as we will also hear, much more remains to be
    done. In particular, we need to survey potentially hazardous
    asteroids that are smaller than the ones cataloged to date, but
    which could do significant damage if they impact or explode
    above the Earth's surface near populated areas.
        That is why Congress directed NASA to ``plan, develop, and
    implement'' a NEO survey program for objects as small as 140
    meters in size, in the NASA Authorization Act of 2005. As a
    result, I am disappointed and concerned that NASA's report to
    Congress failed to provide a recommended option and budget plan
    for such a survey, as directed by the Act. In fact, the report
    says NASA has no plans to do anything beyond the current
    Spaceguard program at this time.
        Equally troubling, one of the NASA witnesses will testify
    that ``NASA would be pleased to implement a more aggressive NEO
    program, if so directed by the President and Congress,'' with
    the implication that Congress has not yet done so. I believe
    section 321 of the NASA Authorization Act, which I quoted
    earlier, is unambiguous. Congress, in fact, has directed NASA
    to ``plan, develop, and implement'' such a program, and we
    would hope that the President would send over a NASA budget
    request that reflects that Congressional direction.
        Today, I want to focus on where we go from here. Given the
    lack of a clear plan in NASA's report to Congress, I hope that
    our witnesses today will be able to provide some guidance to
    the Committee on the best and most cost-effective path forward
    for meeting the goal of surveying NEOs down to 140 meters in
    size. In that regard, there are a number of related questions
    that need to be addressed.
        First, I would like to hear from each of the witnesses
    about the planetary radar capabilities at Arecibo and
    Goldstone. How important are they to addressing the NEO task?
    Second, how can we make the most effective use of capabilities
    being planned or developed by other federal agencies, such as
    LSST and Pan-STARRS, and what role should NASA play in
    supporting them?
        NASA's testimony indicates that it has been providing funds
    to the Air Force's Pan-STARRS project, so that it will be
    capable of providing data on NEO detections. That is an
    interesting development, and it raises the question of whether
    NASA should also be providing funds to other facilities, such
    as Arecibo, and the proposed LSST project, if doing so will
    materially contribute to meeting the NEO survey objectives in a
    responsible, cost-effective manner.
        Third, I would like to know if there are adjustments to
    either the timetable or scope of the NEO survey called out in
    the NASA Authorization Act that would make sense, either by
    allowing more cost-effective approaches on a slightly longer
    timetable, or by focusing on just potentially hazardous
    objects, rather than on all NEOs.
        Fourth, surveying NEOs is just part of the task. If we find
    one that is headed towards Earth, we will need to have good
    options for deflecting it. What priorities should be given to
    developing deflection technologies versus NEO survey systems in
    the coming years?
        And finally, the potential threat posed by Near-Earth
    Objects is not isolated to the United States. What
    contributions are other national and international bodies
    making to the effort? Should more be done?
        Well, as you can see, we have a lot to consider today.
    Fortunately, we have a very distinguished set of witnesses to
    assist us in our oversight task, and I again want to welcome
    all of you, and I look forward to your testimony.
        At this point, the Chair now recognizes my friend, the
    Ranking Member, Mr. Feeney from Florida, for his opening
    remarks.
        [The prepared statement of Chairman Udall follows:]

                   Prepared Statement of Chairman Mark Udall

        Good morning. I'd like to extend a welcome to our witnesses and in
    particular recognize Congressman Luis Fortuno's presence here with us
    today.
        As many of you may recall, today's hearing on Near-Earth Objects
    was originally scheduled for October 11th, but we postponed it in the
    wake of Rep. Jo Ann Davis's untimely death. Thus, before we proceed any
    further, I'd like to express my appreciation to each of the witnesses
    for your willingness to accommodate that postponement and appear before
    us today.
        Your testimony will be invaluable to us as we consider how best to
    proceed in getting a better understanding of the potential threats
    posed by Near-Earth Objects--NEOs, as well as options for dealing with
    them.
        Today's hearing is the latest in a series that stretches back to
    the early 1990s. We have come along way since the late George Brown--
    former Chairman of the Science and Technology Committee--led the first
    efforts to focus congressional attention on the potential threat posed
    by Near Earth asteroids and comets. It has been a bipartisan effort
    over the intervening years, and a lot has been accomplished.
        In that regard, I in particular want to salute the dedication of
    Mr. Rohrabacher in pushing for continued federal initiatives to detect,
    track, and catalog NEOs, as well as to examine ways to deflect them if
    necessary. He has been an effective catalyst for action, and I look
    forward to continuing to work with him on this issue.
        As we will hear from our witnesses, much progress has been made in
    detecting and cataloging the largest NEOs over the last decade.
    However--as we will also hear--much more remains to be done.
        In particular, we need to survey potentially hazardous asteroids
    that are smaller than the ones cataloged to date, but which could do
    significant damage if they impact or explode above the Earth's surface
    near populated areas. That is why Congress directed NASA to ``plan,
    develop, and implement'' a NEO survey program for objects as small as
    140 meters in size in the NASA Authorization Act of 2005.
        As a result, I'm disappointed and concerned that NASA's report to
    Congress failed to provide a recommended option and budget plan for
    such a survey, as directed by the Act. In fact, the report says NASA
    has no plans to do anything beyond the current Spaceguard program at
    this time.
        Equally troubling, one of the NASA witnesses will testify that
    ``NASA would be pleased to implement a more aggressive NEO program if
    so directed by the President and Congress,''--with the implication that
    Congress has not yet done so. I think Sec. 321 of the NASA
    Authorization Act, which I quoted earlier, is unambiguous--Congress has
    in fact directed NASA to ``plan, develop, and implement'' such a
    program. And we would hope that the President would send over a NASA
    budget request that reflects that congressional direction.
        Today, I want to focus on where we go from here. Given the lack of
    a clear plan in NASA's report to Congress, I hope that our witnesses
    today will be able provide some guidance to this committee on the best
    and most cost-effective path forward for meeting the goal of surveying
    NEOs down to 140 meters in size.
        In that regard, there are a number of related questions that need
    to be addressed. First, I'd like to hear from each of the witnesses
    about the planetary radar capabilities at Arecibo and Goldstone. How
    important are they to addressing the NEO task?
        Second, how can we make the most effective use of capabilities
    being planned or developed by other federal agencies, such as LSST and
    Pan-STARRS, and what role should NASA play in supporting them? NASA's
    testimony indicates that it has begun providing funds to the Air
    Force's Pan-STARRS project ``so that it will be capable of providing
    data on NEO detections. . .''
        That's an interesting development, and it raises the question of
    whether NASA should also be providing funds to other facilities such as
    Arecibo and the proposed LSST project if doing so will materially
    contribute to meeting the NEO survey objectives in a responsible, cost-
    effective manner.
        Third, I'd like to know if there are adjustments to either the
    timetable or scope of the NEO survey called out in the NASA
    Authorization Act of 2005 that would make sense--either by allowing
    more cost-effective approaches on a slightly longer timetable or by
    focusing on just potentially hazardous objects rather than on all NEOs.
        Fourth, surveying NEOs is just part of the task. If we find one
    that it is headed towards Earth, we will need to have good options for
    deflecting it. What priority should be given to developing deflection
    technologies versus NEO survey systems in the coming years?
        Finally, the potential threat posed by Near-earth objects is not
    isolated to the United States. What contributions are other national
    and international bodies making to the effort? Should more be done?
        Well, as you can see, we have a lot to consider today. Fortunately,
    we have a very distinguished set of witnesses to assist us in our
    oversight task.
        I again want to welcome all of you, and I look forward to your
    testimony.

        Mr. Feeney. Well, thank you, Mr. Chairman, and I appreciate
    you calling this morning's hearing, although I did tell you as
    I greeted you this morning that this is just one more thing for
    us to worry about, that hadn't been on my list until a couple
    weeks ago, when I saw the original notice of hearing.
        And I want to echo your remarks. We are very grateful to
    the witnesses, because we had to reschedule the hearing on
    short notice, and we thank you, and we are very appreciative
    that you are here today, so that we can accommodate that
    emergency change.
        NASA's Near-Earth Object program, though very modest in
    scale compared to many of the agency's multi-billion dollar
    endeavors, is vitally important, and NASA has been doing an
    exemplary job standing up an office and managing the Nation's
    and world's only survey for potentially hazardous Earth-
    crossing asteroids and comets. I find it distressing that other
    nations haven't, to date, taken a more active role, and I note
    that we have some visitors from Germany here today. We are very
    grateful for their interest.
        NASA began the NEO survey, called the Spaceguard program,
    in 1998, and I note that my colleague, Dana Rohrabacher, who is
    here, was instrumental in advocating that, with the goal of
    detecting and cataloging 90 percent of all potentially
    hazardous asteroids and comets larger than one kilometer in
    diameter within a decade, and it appears to be relatively on
    track to meet that target. Subsequently, a 2003 NASA-chartered
    team of scientists recommended that the survey seek all NEOs of
    140 meters in diameter or larger, reasoning that the smallest
    of these could still inflict large regional impacts if they
    struck the Earth.
        Their recommendations were made part of the 2005 NASA
    authorization legislation, directing NASA to ``plan, develop,
    and implement a Near-Earth Object survey program to detect,
    track, catalog, and categorize Near-Earth Objects equal to or
    greater than 140 meters in diameter.''
        The goal was to get 90 percent completion within 15 years.
    This change in mission is no small matter. As the universe of
    potentially hazardous objects, PHOs, to be detected and
    cataloged increased by a factor of 20, from 1,000 to
    approximately 20,000. The bill also required NASA to complete
    an analysis of alternatives to meet this ambitious goal, and to
    report back with a recommended option. NASA provided such a
    report earlier this year, but did not indicate a preferred
    choice, instead urging the current Spaceguard program be
    allowed to continue its survey for one kilometer and larger
    Near-Earth Objects, that will allow the agency to take
    advantage of opportunities using potential dual use telescopes
    and spacecraft to achieve the goals outlined in the 2005
    authorization.
        Although the 15-year timeline may not be met in all cases,
    NASA's rationale is purely budget-driven, arguing that current
    resources are too constrained. While disappointed, I certainly
    can't disagree or argue with their reasoning.
        At this morning's hearing, it is my hope that we get a
    clearer understanding of NASA's plans to proceed with utilizing
    dual use telescopes and spacecraft, their potential costs and
    schedules, and other facilities that may be utilized, including
    the Arecibo Observatory.
        I hope to hear concrete steps taken by NASA to develop
    cooperative relationships necessary to ensure the requirements
    laid out in the 2005 NASA authorization are met. We will also
    hear about the future of the Arecibo Radio Observatory in
    Puerto Rico, the largest and most powerful such facility in the
    world. Arecibo is operated by the Cornell University under a
    contract with the National Science Foundation (NSF). It appears
    very likely that NSF will significantly reduce its financial
    support, such that Arecibo will have to shut down its radar
    facility. This, I think, would be a mistake. Arecibo has the
    capability of making very precise orbital calculations in a
    short amount of time, a critical feature that optical
    telescopes simply cannot match. And the sum of money at stake
    is on the order of several million dollars a year, an
    investment I think is well worth the return. While NSF may be
    outside the purview of this subcommittee, the ramifications of
    Arecibo's loss to the NEO program begs the discussion.
        I want to first welcome my good friend, Luis Fortuno, to
    today's hearing. I want to also thank all of our guests once
    again, express my appreciation for changing their schedule to
    accommodate our schedule, and I want to thank my Chairman, Mr.
    Udall, and with that, look forward to the discussion.
        [The prepared statement of Mr. Feeney follows:]

                Prepared Statement of Representative Tom Feeney

        Thank you, Mr. Chairman, for calling this morning's hearing. And I
    want to echo Mr. Udall's comments, acknowledging that our originally
    scheduled hearing was postponed on very short notice. I greatly
    appreciate that all of our scheduled witnesses were able to accommodate
    the date change, and I hope notice got out quickly enough to save you
    from unnecessary travel.
        NASA's Near-Earth Object (NEO) program, though very modest in scale
    compared to many of the agency's multi-billion dollar endeavors, is
    vitally important, and NASA has been doing an exemplary job standing-up
    an office and managing the Nation's--and world's--only survey for
    potentially hazardous Earth-crossing asteroids and comets. I find it
    distressing that other nations haven't, to date, taken a more active
    role.
        NASA began the NEO survey, called the ``Spaceguard'' program, in
    1998 with the goal of detecting and cataloguing 90 percent of all
    potentially hazardous asteroids and comets larger than one kilometer in
    diameter within a decade, and it appears to be on track to meet that
    target.
        Subsequently, in 2003 a NASA-chartered team of scientists
    recommended that the survey seek all NEOs of 140 meters in diameter or
    larger, reasoning that the smallest of these could still inflict large
    regional impacts if they struck Earth. Their recommendations were made
    part of the 2005 NASA authorization legislation, directing NASA to
    ``plan, develop and implement a Near-Earth Object Survey program to
    detect, track, catalogue, and characterize. . .near-Earth objects equal
    to or greater than 140 meters in diameter. . .,'' with the goal of 90
    percent completion within 15 years. This change in mission is no small
    matter, as the universe of potentially hazardous objects (PHOs) to be
    detected and catalogued increased by a factor of twenty (from 1000 to
    20,000). The bill also required NASA to complete an analysis of
    alternatives to meet this ambitious goal and to report back with a
    recommended option.
        NASA provided such a report earlier this year but did not indicate
    a preferred choice, instead urging the current ``Spaceguard'' program
    be allowed to continue its survey for 1 kilometer and larger near-Earth
    objects, and to allow the agency to take advantage of opportunities
    using potential dual-use telescopes and spacecraft to achieve the goals
    outlined in the 2005 authorization, although the 15 year timeline may
    not be met in all cases. NASA's rationale is purely budget driven,
    arguing that current resources are too constrained. While disappointed,
    I certainly can't disagree with their reasoning.
        At this morning's hearing, it is my hope that we get a clearer
    understanding of NASA's plans to proceed with utilizing dual-use
    telescopes and spacecraft, their potential costs and schedules, and
    other facilities that may be utilized, including the Arecibo
    Observatory. I hope to hear of concrete steps being taken by NASA to
    develop cooperative relationships necessary to ensure the requirements
    laid out in the 2005 NASA authorization are met.
        We'll also hear about the future of the Arecibo Radio Observatory
    in Puerto Rico, the largest and most powerful such facility in the
    world. Arecibo is operated by Cornell University under a contract with
    the National Science Foundation (NSF). It appears very likely NSF will
    significantly reduce its financial support such that Arecibo will have
    to shut down its radar facility. This, I think, would be a mistake.
    Arecibo has the capability of making very precise orbital calculations
    in a short amount of time, a critical feature that optical telescopes
    cannot match. And the sum of money at stake is on the order of about $2
    million a year, an investment that I think is well worth the return.
    While NSF may be outside the purview of this subcommittee, the
    ramifications of Arecibo's loss to the NEO program begs the discussion.
        I want to welcome my friend, Rep. Fortuno, to today's hearing. I
    also want again to say thanks to our excellent panel of expert
    witnesses for taking time from their busy schedules to be here.
        Thank you, Mr. Chairman.

        Chairman Udall. Thank you, Congressman Feeney. If there are
    Members who wish to submit additional opening statements, your
    statements will be added to the record. Without objection, so
    ordered.
        And in addition, I would also like to include a statement
    for the record from the Planetary Society into today's hearing.
    Without objection, so ordered. [See Appendix 2: Additional
    Material for the Record.]
        At this time, I would like to go ahead and recognize our
    first panel. And we are delighted to have Representative Luis
    Fortuno, the Resident Commissioner of Puerto Rico, with us here
    today, who will be testifying, I think, before the Committee
    for the first time.
        Congressman Fortuno, the floor is yours.

                                    Panel 1

          STATEMENT OF REPRESENTATIVE LUIS FORTUNO, RESIDENT
                       COMMISSIONER, PUERTO RICO

        Mr. Fortuno. Thank you. Thank you, Mr. Chairman. Chairman
    Udall, Ranking Member Feeney, distinguished Members of this
    subcommittee.
        Every day, an enormous quantity of cosmic material falls to
    the Earth. Most burn up on reentry in a harmless way. However,
    NASA predicts that more than 20,000 large, potentially
    dangerous objects pass by the Earth in close proximity, and
    given the proper circumstance, could threaten or severely
    impact our existence. Although the chances of a major impact
    are slim, the consequences are too great to disregard.
        I believe we should continue to advance our knowledge of
    Near-Earth Objects and their potential consequences for life on
    Earth. I commend Congressman Rohrabacher on his effort to
    continue funding for Near-Earth Objects surveillance programs.
    Since 1992, the Spaceguard program's goal was to discover 90
    percent of the NEOs with one kilometer diameter potential by
    2008. Although the success of this program will be substantial,
    there will still be thousands of objects, ranging from 200 to
    500 meters in diameter, that will be overlooked. We must
    enhance our understanding of this phenomenon by studying and
    assessing the threats posed to our environment and to our
    national security.
        According to Director Michael Griffin, NASA does not have
    the funds to carry out a more extensive program. There have
    been suggestions that NASA and the National Science Foundation
    should cooperate to fund the construction of a new ground-based
    telescope to perform tracking functions of Near-Earth Objects
    and other astronomy surveys. I do not think we need to take on
    such a burden, when there is still a great deal of information
    to be gained by utilizing the unique capabilities of the
    Arecibo Observatory in Puerto Rico.
        As the world's largest and most powerful radio telescope,
    the Arecibo Observatory is essential to monitoring and
    surveying NEOs. However, the National Science Foundation has
    threatened to close the observatory in 2011, and NASA has, so
    far, been unwilling to assume funding of the radar required for
    tracking NEOs. Closing the observatory will severely limit our
    ability to quickly and accurately refine the orbits of newly
    emerging threats, and reduce our monitoring capabilities.
        This is why I have introduced H.R. 3737, which directs the
    National Science Foundation and NASA to work together to ensure
    continued full funding of the Arecibo Observatory, and in
    particular, the radar. It is my recommendation and the
    recommendation of 19 of my colleagues, that these agencies
    start working in collaboration and reconsider how they allocate
    their funding.
        Mr. Chairman and Ranking Member Feeney, the Arecibo
    Observatory's radar is the world's most powerful instrument for
    post-discovery characterization and orbital refinement of Near-
    Earth asteroids. Observations performed with the radar are
    critical for identifying asteroids that might be on a collision
    course with Earth.
        I respectfully urge the Committee to consider continuing
    the important work performed by the Arecibo observatory, and
    consider, as well, H.R. 3737, as one potential solution to this
    challenge. The unique capabilities of radar are critically
    important as we work towards fulfilling the 2005 Congressional
    mandate of detecting and characterizing 90 percent of NEOs down
    to 140 meters in diameter.
        A potentially dangerous collision of an asteroid or comet
    is a very real threat. We must take action now to enhance our
    awareness to prevent a catastrophe. A better understanding of
    our skies will not only help us to comprehend the wonders of
    the Earth's environment, but is essential to assessing the
    dangers that may threaten our society.
        The world's most sensitive radio telescope at Arecibo
    Observatory must not be closed. By the way, we don't have final
    numbers, but NSF is determining the cost of dismantling this
    facility and bringing the area back to a greenfield, but it is
    around $200 million. We are dealing with a $4 million gap a
    year, so the numbers are certainly there as well.
        Mr. Chairman and Ranking Member Feeney, thank you for the
    opportunity to provide my views on this issue. I will now ask
    permission to show, in the Committee's flatscreen, some images
    of the Arecibo Observatory, that would help understand the size
    and magnitude of this extraordinary science resource.
        Chairman Udall. Please proceed.
        Mr. Fortuno. Thank you.
        That is an aerial picture of the radio telescope. As you
    see, it is embedded in a number of mountains. That is another
    angle. It is a massive facility. It really is.
        It is visited every year by 300,000 people, 25,000 of them
    are K-12 students. That is it.
        Thank you again, Mr. Chairman.
        [The prepared statement of Mr. Fortuno follows:]

               Prepared Statement of Congressman Luis G. Fortuno

    Chairman Udall and Ranking Member Feeney,

        Every day an enormous quantity of cosmic material falls to the
    Earth. Most burns up on re-entry in a harmless way, however NASA
    predicts that more than 20,000 large, potentially dangerous objects
    pass by the Earth in close proximity and, given the proper circumstance
    could threaten or severely impact our existence. Although the chances
    of a major impact are slim, the consequences are too great to
    disregard. I believe we should continue to advance our knowledge of
    Near-Earth Objects and the potential consequences for our life on
    Earth.
        I commend Congressman Rohrabacher on his efforts to continue
    funding for Near-Earth Objects surveillance programs. Since 1992, the
    Spaceguard program's goal was to discover 90 percent of the NEOs with
    one kilometer diameter potential by 2008. Although the success of this
    program will be substantial, there will still be thousands of objects--
    ranging from 200 to 500 meters in diameter--that will be overlooked. We
    must enhance our understanding of this phenomenon by studying and
    assessing the threats posed to our environment and to our national
    security.
        According to Director Michael Griffin, NASA does not have the funds
    to carry out a more extensive program. There have been suggestions that
    NASA and the National Science Foundation should cooperate to fund the
    construction of a new ground-based telescope to perform tracking
    functions of Near-Earth Objects and other astronomy surveys. I do not
    think we need to take on such a burden, as there is still a great deal
    of information to be gained by utilizing the unique capabilities of the
    Arecibo Observatory in Puerto Rico. As the world's largest and most
    powerful radio telescope, the Arecibo Observatory is essential to
    monitoring and surveying Near-Earth Objects. However, the National
    Science Foundation has threatened to close the Observatory in 2011 and
    NASA has so far been unwilling to assume funding of the radar required
    for tracking NEOs. Closing the Observatory will severely limit our
    ability to quickly and accurately refine the orbits of newly emerging
    threats, and reduce our monitoring capabilities.
        This is why I have introduced H.R. 3737, which directs the National
    Science Foundation and NASA to work together to ensure continued full
    funding of the Arecibo Observatory and in particular, the radar. It is
    my recommendation that these agencies start working collaboratively and
    reconsider how they allocate their funding.
        Mr. Chairman and Ranking Member Feeney, the Arecibo Observatory's
    radar is the world's most powerful instrument for post-discovery
    characterization and orbital refinement of near-Earth asteroids. The
    observations performed with the radar are critical for identifying
    asteroids that might be on a collision course with Earth. I
    respectfully urge the Committee to consider continuing the important
    work performed by the Arecibo Observatory and consider, as well, H.R.
    3737 as one potential solution to this challenge. The unique
    capabilities of radar are critically important as we work towards
    fulfilling the 2005 congressional mandate of detecting and
    characterizing 90 percent of near-Earth Objects down to 140 meters in
    diameter.
        A potentially dangerous collision of an asteroid or comet is a very
    real threat. We must take action now to enhance our awareness to
    prevent a catastrophe. A better understanding of our skies will not
    only help us to comprehend the wonders of the Earth's environment, but
    is essential to assessing the dangers that may threaten our society.
    The world's most sensitive radio/radar telescope at Arecibo Observatory
    must not be closed.
        Mr. Chairman and Ranking Member Feeney, thanks for the opportunity
    to provide my views on this issue.

                                   Discussion

        Chairman Udall. Thank you, Resident Commissioner Fortuno.
    This testimony has been very helpful, and I want to pay
    particular note to the costs that might be involved in
    decommissioning this site, and we look forward to getting
    firmer numbers, because the obvious argument would be you would
    take the money that would be used in decommissioning the site,
    and actually operate it for a certain number of years or even
    decades into the future.
        At this time, I would be happy to recognize Mr. Feeney, if
    he has any questions for his colleague, Mr. Fortuno.

                        Impact of Shutting Down Arecibo

        Mr. Feeney. Well, thank you, Mr. Chairman, and thank you
    for your testimony, Congressman. You know, as I read through
    the materials and the different NSF and NASA projections, and
    discussion of this important issue, all of them suggest that
    Arecibo is very important to our capabilities.
        Any decision to close it down seems to be purely budget-
    driven, and so that I hope, as we get the numbers and the
    estimates for what it would cost, and what the impact would be
    of shutting it down, that you will immediately provide this
    committee, and also, the Committee with jurisdiction over NSF,
    with those numbers. Because if this is entirely cost-driven,
    then we need to, as we are understanding the advantages that
    everybody acknowledges, we also need to know that the, of
    keeping it open, that the disadvantages of closing it also will
    have a significant cost many, many times what it costs on an
    annual basis to keep it alive.
        Our next panel includes some very distinguished witnesses.
    One of them, for example, Mr. Yeomans' testimony will tell us
    that Arecibo and Goldstone complement one another and provide
    two very different functions. That is very important, because
    while the one telescope is capable of identifying Near-Earth
    Objects that may be a threat, it is Arecibo that helps us
    determine the exact threat to the Earth. And the fascinating
    thing is that we have the capability with Arecibo, at least
    with the large objects that we have now proceeded to catalog,
    and we are very near our goal, or at least we are on track. Mr.
    Yeomans will testify that once we find the vast majority of
    them, they can be tracked, cataloged, and then ruled out or in
    as threats during the next 100 years or so.
        I think the people of the world would be very grateful to
    know, especially with 100 years notice, that there may be a
    catastrophe, driven by a Near-Earth Object. But most
    importantly, we have the technological capabilities to actually
    deflect or to eliminate the damage with that type of notice,
    and again, Mr. Yeomans and our other witnesses will testify to
    that.
        So, Mr. Fortuno, I know that Congressman Rohrabacher had a
    question. I wanted to yield a few minutes to him, but if you
    could tell us the impact, because probably uniquely you are
    able to tell us this question, the impact on Puerto Rico if we
    shut Arecibo down, in the next year or two, what the local
    impact would be. We will get to the technical experts. I had
    assumed you are not an astrophysicist. Neither am I. Don't feel
    bad about that. Go ahead and tell us the impact on Puerto Rico.
        Mr. Fortuno. Thank you, and thank you for your comments.
    Certainly. The impact, we are estimating that it will be about
    $50 million for the Arecibo area, actually. On top of that, the
    impact on those kids that may have an interest in science and
    technology, that will not be able, otherwise, to visit a
    facility like this one. If I may add, the Arecibo radio
    astronomy led to the first discovery of a planet outside of our
    own solar system, to the first discovery of a binary pulsar,
    resulting in a Nobel Prize, and the first detailed, three
    dimensional mapping of how galaxies are distributed in the
    universe.
        So, it is really, from the scientific point of view, it
    will be priceless to our young students, that have an interest
    in this area.

                                  George Brown

        Mr. Feeney. Any remaining time, I would be pleased to yield
    to Congressman Rohrabacher.
        Mr. Rohrabacher. Thank you very much. And thank you, Mr.
    Chairman, for your kind words, and bipartisan words, and
    holding the hearing. I can't help but notice George Brown's
    picture right back there. I don't know how many people in this
    room knew George Brown. I knew him. He was the Chairman here
    when I came here 20 years ago, and he was a wonderful human
    being. He was a man of integrity, and I am very pleased that
    some of the work that I have done in this area actually bore
    the name of George Brown, because he was just a fine person,
    and had that very same bipartisan spirit that Mr. Udall has
    been trying to demonstrate here today.
        And hopefully, when we are talking about things that might
    threaten the entire planet, that may well motivate Congress to
    be bipartisan, if nothing else does. I mean, after all, it is
    just the entire planet that may be destroyed. But George Brown
    really gave me personal guidance, and his integrity was very
    much appreciated.

                   Importance of Arecibo With Regard to Cost

        When we are talking about Arecibo, I want to, of course,
    recognize the hard work that Congressman Fortuno is actually
    putting into this effort. It is a heroic effort. I am very
    pleased to be assisting him. But of course, we are not trying
    to do anybody any favors here. This isn't an issue of doing
    anyone a favor.
        First and foremost, the Arecibo telescope is doing work
    currently that would cost us more, even outside of the area of
    Near-Earth Objects. Even outside the area of Near-Earth
    Objects, the Arecibo telescope is doing work that would be more
    costly to do if, for example, we would send satellites. I
    understand we sent a mission to Venus that cost a certain
    amount of money, but the actual images that we got back from
    Arecibo were better than sending the probe up to Venus. Now,
    how much did that cost us? I mean, it probably cost us enough
    to keep Arecibo going for a decade.
        And clearly, also, when you look at the shutdown costs,
    which has been mentioned here, if you take all of that
    together, well, you could probably put that in the bank, and
    the interest on that money would probably keep the Arecibo
    telescope going. And this exemplifies sort of the screwball
    nature of the way we do business up here on Capitol Hill
    sometimes. And if we let this asset be set aside and closed
    down, it would be a tragedy, but also, as I say, very symbolic
    of the fact that we can't even do our job in Capitol Hill
    enough to take a very cost-effective asset, and something that
    is doing a mission that is vitally important to our security,
    that we can't even get ourselves together enough to get a
    limited amount of money to keep that project going. So, I think
    this is very symbolic, and that we should all be working
    together on this, and we are working on this.
        Just a question. Now, you mentioned the kids that there
    are, and you mentioned how this would affect your economy. Tell
    me, if we didn't know that a Near-Earth Object was coming, and
    thus, one snuck by and landed in the Caribbean, would it be
    possible that Puerto Rico would be wiped out?
        Mr. Fortuno. Well, actually, anything can happen, but
    certainly, you could have the East Coast of the United States,
    not just the Caribbean, affected by something like that. And
    again, the cost-effectiveness of this facility has to be
    highlighted, and I thank you, Mr. Rohrabacher, for your
    leadership on this issue, not just on Arecibo, the issue in
    general.
        I think it is an issue that we need to devote resources and
    time to it, and again, I thank the Chairman and all the Members
    of this subcommittee.
        Mr. Rohrabacher. Shutting down Arecibo means that we are
    intentionally putting ourselves in a position of ignorance of
    potential threats, and with that ignorance may come bliss for a
    while. However, let us note it also not only gives us
    ignorance, but it also prevents us from having any chance of
    deflection if there is a threat. So, we are putting ourselves
    in a position of being ignorant of a potential threat, and
    also, making ourselves incapable of responding to the potential
    threat. And Arecibo is in the middle of this. No one should
    take us seriously about watching out for the long-term
    interests if we let this asset go.
        So, I thank you very much, and I am looking forward to
    working with you, working with the Ranking Member, and working
    with the Chairman. We need to work on this, and show that we
    can actually--if we can't get this done, we can't get anything
    done. I mean, it is as simple as that.
        Mr. Fortuno. Thank you.
        Mr. Rohrabacher. And thank you for your hard work.

                                Visiting Arecibo

        Chairman Udall. I thank the gentleman from California. I
    would note, for the record, that my colleague from Texas, Mr.
    Lampson, is here. There is nobody more passionate an advocate
    for NASA and all that NASA does. I do believe he does not have
    a question----
        Mr. Lampson. No, I don't.
        Chairman Udall.--for his colleague from Puerto Rico.
    Resident Commissioner, if you----
        Mr. Lampson. I do look forward to visiting, however.
        Chairman Udall. I am sorry, you----
        Mr. Lampson. I do look forward to visiting the facility
    some time.
        Chairman Udall. That is an open offer, I am sure.
        Mr. Fortuno. It is a beautiful facility, but actually, some
    time between December and March is the best time to visit.
        Chairman Udall. Well, I again want to thank the Resident
    Commissioner, and at this time, would be pleased to excuse you.
    I know you have other responsibilities and a busy schedule.
    Thank you again for joining us.
        Mr. Fortuno. Thank you, Mr. Chairman.
        Chairman Udall. At this time, as the Resident Commissioner
    departs, we will pause, while the second panel can take your
    seats and get comfortable, and then, we will begin the
    presentations from the second panel in a few minutes.
        I want to welcome the panel, and at this time, it seems
    appropriate to introduce all of the witnesses that have joined
    us. I would, before I do so, just let the panel know, and the
    others who are here with us, that there are votes pending at
    some point in the next 25 to 30 minutes. We will, I think, have
    a series of at least two votes, and we will do all we can to
    move the testimony forward, and then we will recess for 40
    minutes, and then reconvene the hearing.
        Let me begin here, on my left to the audience's right, with
    Dr. James Green, who is the Director of the Planetary Science
    Division at NASA. Next to him is, moving from left to right
    again, is Dr. Scott Pace, who is the Associate Administrator of
    the Office of Program Analysis and Evaluation at NASA. Third on
    the panel, Dr. Donald Yeomans, who is the manager of the Jet
    Propulsion Laboratory's Near-Earth Object Program Office.
    Proceeding down the line, Dr. Campbell, Dr. Donald Campbell,
    who is a Professor of Astronomy at Cornell University, and a
    former Director of the Arecibo Observatory. Next to Dr.
    Campbell, Dr. J. Anthony Tyson, who is a Professor of Physics
    at the University of California, Davis, and a Director of the
    Large Synoptic Survey Telescope Project. And our last witness
    on the second panel, we have Mr. Russell ``Rusty'' Schweickart,
    former Apollo astronaut, Lunar Module pilot on Apollo IX, and
    the Chairman and Founder of the B612 Foundation.
        Welcome, gentlemen, to all of you. We are really pleased to
    have you here today. I think all of you know, I think many of
    you have been before the Committee before, that your spoken
    testimony is limited to five minutes each, after which the
    Members of the Subcommittee will have five minutes each to ask
    questions.
        So, Dr. Green, we will begin with you. The floor is yours.

                                    Panel 2

     STATEMENT OF DR. JAMES L. GREEN, DIRECTOR, PLANETARY SCIENCE
    DIVISION, SCIENCE MISSION DIRECTORATE, NATIONAL AERONAUTICS AND
                      SPACE ADMINISTRATION (NASA)

        Dr. Green. Thank you, Mr. Chairman and Members of the
    Committee, for the opportunity to present information on NASA's
    important efforts to find Near-Earth Objects or NEOs.
        At the request of Congress, NASA currently conducts a very
    successful NEO search program designed to find 90 percent of
    the NEOs greater than one kilometer in diameter. Since the
    program started in 1998, NASA has funded over $30 million in
    NEO search efforts. During this time period, NASA has found, as
    of Monday, I checked, 727 one kilometer or larger Near-Earth
    asteroids and 65 Earth-approaching comets, as well as 4,198
    smaller NEOs.
        At the current discovery rate, we will have discovered more
    than 50 large NEOs by the end of 2008, bringing us very close
    to achieving our 90 percent discovery goal, according to our
    current estimate of roughly 940 greater than one kilometer size
    NEOs.
        NASA currently funds four teams that operate eight ground-
    based telescopes, of mostly one meter class, dedicated to
    searching the skies and detecting NEOs. All NEO observations
    that are collected are sent to an international clearinghouse
    for small bodies. This organization is called the Minor Planet
    Center. The Minor Planet Center determines the initial orbit
    for any newly discovered NEO, so that observatories worldwide
    may observe the object and confirm its existence. Once an NEO's
    orbit has been determined, its potential for impacting the
    Earth is assessed. Over 99 percent of the objects discovered by
    our search efforts so far have no potential for Earth impacts
    over many millennia, but a smaller number, which do, are tagged
    potentially hazardous objects.
        Now, more detailed and refined analysis of potentially
    hazardous objects' orbits is then conducted by NASA's NEO
    Program Office at the Jet Propulsion Laboratory. Observations
    on potentially hazardous objects are also automatically
    received, their orbits updated to determine the level of
    probability of impacting the Earth in the next 100 to 200
    years. The results of this analysis is constantly updated and
    published on our NEO program website.
        Now, the National Science Foundation's Arecibo Radio
    Telescope, although it has no use in detecting NEOs, does
    indeed provide us important observations for NEOs that pass
    within 20 million miles of the Earth. Arecibo plays that
    important role in refining the orbit, allowing us to obtain
    information about the object's size, its shape, and its spin
    rate. The only other facility currently being used by NASA for
    routine planetary radar is NASA's own Goldstone facility, which
    is part of our Deep Space Network. To date, no international
    facilities are capable of performing this feat on a regular
    basis.
        Previous planetary spacecraft missions have not contributed
    directly to detecting NEOs. NASA missions, such as the Near-
    Earth Asteroid Rendezvous, Stardust, Deep Impact, and the
    Japanese Hayabusa 1 missions, have all brought us fascinating
    information on NEO composition, origin, and migration into the
    inner solar system. The recently launched Dawn mission will
    travel past the orbit of Mars and into the main asteroid belt,
    observing both Vesta and Ceres, which are the largest objects
    in that region. The asteroid belt has been shown to be the most
    probable region where these objects are coming from, that we
    now classify as NEOs.
        In our report to Congress, requested by the 2005 Act, NASA
    recommended that the current program be continued, and that we
    would look at opportunities for potential dual use ground-based
    telescopes, spacecraft, and also, partner with other agencies
    as feasible. For example, we are actively planning to use the
    Air Force Panoramic Survey Telescope and Rapid Response System,
    also referred to as Pan-STARRS, after it becomes operational
    with its very first telescope next year. When Pan-STARRS is
    completed, and with its intended four telescope configuration,
    by 2011, this system alone could discover up to 70 percent of
    the potentially hazardous objects larger than 140 meters by
    2020.
        It is important to note that no significant NEO detection
    efforts are currently conducted outside of NASA. However, there
    is growing interest in international communities to contribute.
    Most recently, the United Nations Committee on the Peaceful
    Uses of Outer Space recently established a working group on
    NEOs, to encourage more international work on the issue.
        Other opportunities are beginning to materialize; that can
    help us in these detection efforts. NASA's own Wide-Field
    Infrared Survey Explorer, which is being developed for a late
    2009 launch, is an astrophysics mission designed to map the
    infrared sky. However, it is also capable of detecting many
    asteroids, in which a portion will indeed be NEOs.
        We have also been discussing with the Canadian Space Agency
    how their upcoming Near-Earth Orbit Surveillance Satellite
    (NEOSSat) mission would be able to contribute to NEO research
    and detection, and other important missions like these are
    being planned by the European Space Agency, the Japanese
    Aerospace Exploration Agency, and for which we are in close
    communications with.
        In closing, let me again thank you for the opportunity to
    appear at this hearing, and I would be happy to respond to any
    of your questions.
        [The prepared statement of Dr. Green follows:]

                      Prepared Statement of James L. Green

        Mr. Chairman and Members of the Subcommittee, thank you for the
    opportunity to appear today to discuss the goals and accomplishments of
    NASA's Near-Earth Objects (NEOs) Observation Program. The
    Subcommittee's invitation to testify identified a series of six
    questions, and I have structured my testimony around your specific
    concerns.

    Question 1: Please describe NASA's NEO Program and the infrastructure
    and operations in place to support the ongoing Survey (e.g., use of
    observatories, survey processing and NEO databases, analysis of
    identified objects, research, and sensor development)?

        To achieve NASA's stated goal of finding over 90 percent of the
    NEOs greater than one kilometer in diameter, the Agency's NEO
    Observation Program currently funds four survey teams that operate
    eight ground-based telescopes of mostly one meter class apertures
    essentially dedicated to the NEO search effort. Two of the teams are
    sponsored by the University of Arizona Lunar and Planetary Laboratory,
    Tucson, Arizona, one by Lowell Observatory in Flagstaff, Arizona, and
    one by the Massachusetts Institute of Technology Lincoln Laboratory.
    Each team conducts independent operations for 14 to 20 nights per
    month, as weather permits, avoiding approximately a week on either side
    of the full moon when the sky is too bright to detect these extremely
    dim objects from the ground.
        All collected observations believed to be of known or previously
    unknown NEOs are sent to the international ``clearinghouse'' for small
    body observation data, the Minor Planet Center (MPC). The MPC maintains
    the database of observations and orbits on all known small bodies
    (asteroids, comets, dwarf planets, Kuiper Belt Objects (KBO), etc.) in
    the Solar System under the sanction of the International Astronomical
    Union. It is hosted by the Smithsonian Astrophysical Observatory's
    Center for Astrophysics in Cambridge, Massachusetts, but is largely
    funded by NASA. The MPC verifies and validates the observations by
    determining if they are of an already known object (by comparing them
    to the known orbits), or are indeed a new discovery. The MPC then
    determines and publishes an initial orbit for the new discovery so that
    observatories world-wide may look for the object and confirm its
    existence. Sometimes it takes a few nights of additional observations
    to adequately determine, or ``secure,'' the orbit of a new object so
    that it may be regularly observed.
        Once a new object's orbit is secured, its potential for impacting
    the Earth is assessed. Well over 99 percent of all objects discovered
    (which also include Main Belt Asteroids, comets, Trojans, Centaurs and
    KBOs) have no potential for Earth impact even over many millennia, but
    the small fraction which do are tagged as Potentially Hazardous Objects
    (PHOs). More detailed and refined analysis of a PHO's orbit is
    conducted by NASA's NEO Program Office at the Jet Propulsion Laboratory
    in Pasadena, California, which also aids in coordinating the activities
    and operations of NASA's NEO projects. Observations on PHOs are
    automatically forwarded to JPL and their orbits updated with high
    precision analysis to determine a level of probability of the object
    impacting the Earth in the next 100 to 200 years. The results of this
    analysis is constantly updated and published on the NEO Program website
    at http://neo.jpl.nasa.gov.
        Since the program's inception in 1998, NASA has funded over $30M in
    NEO search efforts using funds from the Science Mission Directorate's
    Research and Analysis program. To date, these efforts have found the
    vast majority of the 724 one-kilometer Near Earth Asteroids and 64
    Earth approaching comets now known, as well as the 4,128 known smaller
    NEOs. At the current discovery rate, we will have found about 50 more
    NEOs larger than one kilometer by the end of 2008, bringing us very
    close to achieving our 90 percent goal, measured against the current
    estimate of about 940 total one-kilometer objects. This work has
    retired the majority of the risk that Earth could be struck by a large
    asteroid in the foreseeable future.

    Question 2: What roles do other U.S. Government institutions,
    universities, private and not-for-profit organizations, and
    international entities play in contributing to the NEO Survey and how
    is NASA coordinating with these institutions?

        As discussed above, NASA does not directly own or operate any of
    the NEO Survey assets, but fully or partially funds several
    universities and private institutions to conduct the necessary elements
    of the survey using existing ground-based astronomical facilities. The
    University of Arizona (UofA) operates most of the search telescopes,
    either directly or in partnership with others. Two telescopes are
    operated at Kitt Peak by the UofA Spacewatch project, while the UofA
    Catalina Sky Survey operates two telescopes at Mt. Lemmon Observatory
    and one in partnership with the Australian National Observatory at
    Siding Spring Observatory in New South Wales, Australia, which is
    currently our only southern hemisphere survey site. Lowell Observatory,
    a private institution, operates a smaller search telescope outside
    Flagstaff, Arizona. The remaining search team, funded by NASA at MIT/
    Lincoln Laboratory, operates on two U.S. Air Force-owned one-meter
    class telescopes at the Stallion Air Force Station on White Sands
    Missile Range near Socorro, New Mexico. The Minor Planet Center is
    operated by the Smithsonian Astrophysical Observatory using mostly NASA
    funding, and the NEO Program Office is at the Jet Propulsion
    Laboratory, managed by the California Institute of Technology.
        No significant NEO detection efforts are currently conducted by the
    international community. Less than two percent of NEOs detected in the
    last ten years were found by systems other than those funded by NASA.
        Currently, the only organized work in the international community
    that is significant to the NEO Survey is the NEO Dynamics Site
    (NEODyS), operated by the University of Pisa in Italy. NEODyS conducts
    independent analysis on NEO orbits similar to that performed by NASA's
    NEO Program Office at JPL. JPL and NEODyS constantly compare results
    they obtain for PHO orbits and predicted impact probabilities. If the
    results from one vary significantly from the other, they redo their
    analyses until they can resolve the discrepancy. This work offers a
    completely independent check of impact prediction results prior to an
    announcement of any significant threat.
        Also worth noting is the current significant role for new discovery
    follow-up observations conducted world-wide by a dedicated amateur
    astronomer community. Through its website, the MPC supplies position
    information on newly discovered objects and solicits observations
    needed to improve the orbit from anyone who may want to attempt the
    work. Much of these follow-up observations are obtained by amateur
    astronomer individuals or clubs with relatively sophisticated but
    smaller telescope systems. However, once NASA moves the search to
    objects much smaller than one kilometer, this work quickly becomes
    beyond the capabilities of these amateur systems.
        Coordination of efforts is largely voluntary through the use of
    information published on the MPC and NEO Program Office websites. The
    competitive nature of the grant program used to finance the search
    teams has encouraged them to make improvements in their systems and
    data processing to maintain their detection rates. This community meets
    either in the U.S. or internationally annually, on average, to discuss
    progress and improvements to the survey effort. In addition, last year
    the United Nations Committee on the Peaceful uses of Outer Space
    (COPUOS) established an Action Team on NEOs within its Scientific and
    Technical Subcommittee to encourage more international work on this
    issue. The Action Team is focused on identifying gaps in efforts and
    coordination within the international community, as well as
    recommending improvements. NASA is charter member of this new group.

    Question 3: How do spacecraft missions to comets and asteroids, as well
    as other scientific spacecraft, contribute to the NEO program?

        Currently, spacecraft missions do not contribute to the detection
    of NEOs. However, space missions do provide the most significant and
    detailed information on what we know about the character and
    composition of them. NASA Discovery missions such as the Near-Earth
    Asteroid Rendezvous (NEAR), Stardust, Deep Impact, and the Japanese
    Hyabusa mission have contributed important information to our
    understanding of the origin of comets and asteroids, providing insight
    on their evolution into the inner Solar System near the Earth, their
    structure and physical properties, and their composition. The recently
    launched Dawn mission will travel to the two largest objects in the
    Main Belt of Asteroids--Vesta and the dwarf planet Ceres. This area of
    the Solar System has been shown to be the region of origin for most of
    the objects that now are near Earth, and the Dawn mission will tell us
    many things about their nature. Other significant contributions by
    spacecraft include studies by the Hubble Space Telescope, Spitzer,
    Galileo, and other asteroid and comet flybys performed by several Solar
    System exploration missions.
        Not only are these data important to the development of concepts to
    deal with any impact threat an NEO may pose, but they are also critical
    to an understanding of the nature NEOs for possible destinations and
    resources in our future exploration of the Solar System.
        While NASA does not have any formal responsibility for the task of
    mitigation, scientific missions such as Deep Impact and the current
    Dawn mission to Vesta and Ceres provide information that may be
    critical to planning an asteroid deflection. Likewise, many of the
    systems and technologies that are being developed for exploration
    missions are directly applicable to mitigation missions. These
    capabilities are the hallmarks of a robust, space-faring nation.

    Question 4: What is the Arecibo facility's role in the detection,
    tracking, and characterization of Near-Earth Objects, and what
    alternatives, if any, exist to carry out its role if the facility is
    shut down? How do the capabilities of those alternatives compare to
    those of the Arecibo facility?

        The National Science Foundation's Arecibo Radio Telescope facility
    has had no useful role in the detection of NEOs--its technical
    characteristics make it incapable of conducting searches for these
    relatively small and distant objects. However, once we know the
    position of an object is accessible by a focused radar beam, Arecibo
    plays an important role in the quick refinement of the orbit to a
    precision not obtainable by other means, and for understanding the
    object's size, shape and spin rate. Arecibo also aids in the detection
    of possible binary objects, (15 percent of NEOs), which in turn
    provides data that can be used to determine their mass. When an object
    passes close enough to the Earth to achieve a measurable radar return
    (about 20 million miles depending on the size), the use of radar is one
    of several valuable tools for obtaining additional information about
    these objects.
        The only other facility currently being used by NASA for routine
    planetary radar is NASA's own Goldstone facility, part of our Deep
    Space Network (DSN) for communication with spacecraft on missions
    beyond Earth's orbit. No international facility is capable of
    performing this feat on a regular basis.
        There are significant differences with the planetary radar
    capability at Arecibo compared to Goldstone. The Goldstone radar is a
    70-meter steerable dish, allowing it to access objects significantly
    lower to the horizon than the more limited sky area accessible to the
    limited pointing capability of the Arecibo radar. However, Arecibo is
    twice as powerful as Goldstone and has a much larger (304 meter)
    collection dish, which allows it to observe objects significantly
    farther away than Goldstone.

    Question 5: Will NASA's current NEO program satisfy the requirement
    established in Sec. 321(d)(1) of the NASA Authorization Act of 2005,
    and if not, what is NASA's plan for satisfying that requirement?

        Although the current systems funded by NASA are capable of
    detecting objects smaller than one kilometer in size, the objects must
    come significantly closer to the Earth than a one kilometer object
    needs to in order to be detected. It would take timescales much longer
    than 15 years to observe 90 percent of these objects with the systems
    we currently use.
        As outlined in the report NASA submitted to Congress on March 7,
    2007, pursuant to direction in section 321 of the NASA Authorization
    Act of 2005 (P.L. 109-155), the Agency recommended that the current
    survey program, funded at approximately $4M annually, be continued. In
    addition, NASA indicated that the Agency would look for opportunities
    using potential dual-use telescopes and spacecraft--and to partner with
    other agencies as feasible--to attempt to achieve the legislated goal
    within 15 years. Several alternatives as to how this might be
    accomplished were presented and analyzed in the March 7 report.
    However, due to current budget constraints, it is not possible for NASA
    to initiate a new program. The costs for the alternative programs
    ranged from $470M to in excess of $1.0B over 10 to 19 years, depending
    on how aggressive of a timeline would be pursued.
        The current NEO program is fully funded through 2012. In addition,
    NASA is initiating plans to use other survey systems to increase the
    survey's detection sensitivity and rates. For example, NASA has begun
    providing funds to the Air Force Panoramic Survey Telescope and Rapid
    Response System (Pan-STARRS) project so that it will be capable of
    providing data on NEO detections after it starts operations on its
    first telescope in the next year. If the Air Force continues to fund
    this project to its intended four telescope configuration by 2010, this
    system alone could discover over 70 percent of the potentially
    hazardous objects larger than 140 meters by 2020. NASA is also
    assessing the upgrades that must be instituted at the Minor Planet
    Center to absorb the substantial increase in new detection data that
    this system will provide.
        Finally, NASA is also assessing what already planned spacecraft
    might contribute to the detection effort. A leading example for
    possible dual-use is the Wide-field Infrared Survey Explorer (WISE).
    Currently being developed for a late 2009 launch for a six-month
    astrophysics mission to map the infrared sky, the WISE instrument is
    also capable of detecting many asteroids, of which a portion will be
    NEOs. We are investigating improvements to the timeliness of the
    spacecraft's data down-link and archival plans to increase its utility
    for NEO detections, as well as a possible extended mission to double
    the time available to detect these objects. The science community may
    propose a NEO survey mission under the competitively-selected Discovery
    program.

    Question 6: What plans, policies, or protocols does NASA have in place
    in the event that a previously unknown object on a near-term impact
    trajectory is detected?

        NASA has an NEO contingency notification plan to be utilized in the
    very unlikely event an object is detected with significant probability
    of impacting the Earth. The plan establishes procedures between the
    detection sites, the Minor Planet Center, the NASA NEO Program Office
    at JPL, and NASA Headquarters to first quickly verify and validate the
    data and orbit on the object of interest, and then up-channel confirmed
    information in a timely manner to the NASA Administrator. These
    procedures were first exercised with the discovery of the object now
    known as Apophis, which was found in December 2004 in a hazardous orbit
    but determined to not have a significant probability of impacting the
    Earth in the near-term. NASA will continue to refine this internal
    contingency plan, and begin work with other U.S. Government agencies
    and institutions when directed.
        Again, thank you for the opportunity to testify today, and I look
    forward to responding to any questions you may have.

                          Biography for James L. Green

        Dr. Green received his Ph.D. in Space Physics from the University
    of Iowa in 1979 and began working in the Magnetospheric Physics Branch
    at NASA's Marshall Space Flight Center (MSFC) in 1980. At Marshall, Dr.
    Green developed and managed the Space Physics Analysis Network, which
    provided many scientists, all over the world, with rapid access to
    data, other scientists, and specific NASA computer and information
    resources. In addition, Dr. Green was a safety diver in the Neutral
    Buoyancy tank making over 250 dives until he left MSFC in 1985.
        From 1985 to 1992 he was the Head of the National Space Science
    Data Center (NSSDC) at Goddard Space Flight Center (GSFC). The NSSDC is
    NASA's largest space science data archive. In 1992 he became the Chief
    of the Space Science Data Operations Office until 2005 when he became
    the Chief of the Science Proposal Support Office. While at GSFC, Dr.
    Green was a co-investigator and the Deputy Project Scientist on the
    Imager for Magnetopause-to-Aurora Global Exploration (IMAGE) mission.
    From 1992 to 2000 he was also the Deputy Project Scientist for Mission
    Operations and Data Analysis for the Global Geospace Science Missions
    WIND and POLAR. He has written over 110 scientific articles in referred
    journals involving various aspects of the Earth's and Jupiter's
    magnetospheres and over 50 technical articles on various aspects of
    data systems and computer networks.
        In August 2006, Dr. Green became the Director of the Planetary
    Science Division at NASA Headquarters. Over his career, Dr. Green has
    received a number of awards. In 1988 he received the Arthur S. Flemming
    award given for outstanding individual performance in the federal
    government and was awarded Japan's Kotani Prize in 1996 in recognition
    of his international science data management activities.

        Chairman Udall. Thank you, Dr. Green. Dr. Pace.

     STATEMENT OF DR. SCOTT PACE, ASSOCIATE ADMINISTRATOR, PROGRAM
        ANALYSIS AND EVALUATION, NATIONAL AERONAUTICS AND SPACE
                         ADMINISTRATION (NASA)

        Dr. Pace. Thank you, Mr. Chairman. Members of the
    Committee, thank you for the opportunity.
        I would like to review some of the findings and
    recommendations of the report that we provided to the Congress
    in response to the Authorization Act of 2005. The principal
    findings of the report to Congress were the result of a study
    led by my Office. The Study Team conducted an analysis of
    alternatives, with inputs from several government agencies,
    international organizations, and representatives of private
    organizations. I think that we covered a wide spectrum of views
    of the scientific and technical community in the effort.
        NASA recommended that the existing Spaceguard survey
    program continue, as currently planned. NASA would also take
    advantage of opportunities using potential telescopes, such as
    the Large Synoptic Survey Telescope, and the proposed Panoramic
    Survey Telescope, otherwise known as Pan-STARRS, that you heard
    mentioned, along with potential dual use spacecraft, some
    partnerships with other agencies, as feasible, to make progress
    toward achieving the legislative goal.
        However, I have to say that due to budget constraints, NASA
    cannot initiate a new program beyond Spaceguard at this time,
    and however, as also was noted, that NASA, it is fair to say,
    would be pleased to implement a more aggressive Near-Earth
    Object program if, in fact, so directed by the President and
    Congress. Given the constrained resources and strategic
    objectives that the agency has already been tasked with, I
    would have to say that NASA cannot place a new NEO program
    above current scientific and exploration missions. But I
    imagine that will be the subject of dialog and discussion with
    you, and see how we can move forward.
        The goal of finding 90 percent of potentially hazardous
    objects 140 meters in diameter and larger is one to two orders
    of magnitude more technically challenging than the existing
    Spaceguard mission. To reach the goal within 10 to 15 years
    would require at least one new dedicated ground or space
    observatory, and we can share with other folks, but to really
    hit the goal, you need a dedicated facility.
        Cataloging the number of total objects, say 100,000, at the
    rate they would be discovered, around 30 to 50 a day, would
    require a new tracking and data management infrastructure,
    whose ongoing operation may constitute a sizable portion of the
    total cost. A delay of five to 10 years in achieving the
    legislation goal, we think, carries little additional risk when
    the impact interval for 140 meter objects is about once every
    5,000 years. We think there is time to do the survey right.
    This rate of impact indicates the system may need to operate,
    conducting searches, tracking objects, for an extended period
    of time before identifying a credible threat, and I would like
    to describe really three periods in that process.
        Today, we know where a few 140 meter objects are, but we
    know little about when or if they will impact. We are ignorant.
    For the initial 10 to 20 years the survey is progressing, the
    average warning time will rise, the unwarned impact risk will
    gradually decline, and during this period, potentially decades
    of warning will become likely.
        After 10 to 20 years of the survey, a steady state period
    will be reached, where unwarned impacts of potentially
    hazardous objects would be highly unlikely. Centuries of
    warning time become possible in a steady state period.
        The NASA identified, in its report, an exemplar NEO survey
    program, with estimates for its architectural costs that, if
    funded, could achieve the specified goal of surveying 90
    percent of potentially hazardous objects by the end of 2020.
    This would occur by constructing or funding a dedicated survey
    asset, combined with NASA partnerships with other agencies on
    future optical ground-based observatories. Details of the
    exemplar program were provided in our report, and again, we
    would be happy to discuss them.
        I want to caution, however, that the budget estimates in
    the report are what we call architecture costs, and a lot more
    rigorous analysis would be needed before a program to be
    assessed for implementation. So, more work needs to be done on
    those cost estimates.
        Finally, the current NEO Spaceguard survey program, really
    without any augmentation, would not be able to satisfy the
    requirements of the Authorization Act. In the Act right now,
    the requirements of the survey program are to find only NEOs
    greater than a kilometer in diameter, and therefore, if we
    focused on things smaller than that, 140 meters, it would
    require additional effort. Without major augmentation, NASA
    estimates that we could detect 14 percent of the 140 meter or
    larger potentially hazardous objects by 2020.
        In our cooperative efforts with Air Force, the Pan-STARRS
    program, it would be capable of providing data on NEO
    detections after operations start. We think that this system
    alone could discover about 70 percent of potentially hazardous
    objects larger than 140 meters by 2020. So, we think there are
    some promising approaches.
        While NASA does not have any formal responsibility for the
    task of NEO mitigation, as mentioned, scientific missions such
    as Deep Impact and Dawn provide information that may be
    critical to planning and asteroid deflection, and likewise,
    many of the systems and technologies that are being developed
    for exploration are directly applicable to mitigation missions.
    These capabilities are the hallmarks of a robust and
    spacefaring nation, capable of the many tasks that may be
    assigned to it.
        Thank you, Mr. Chairman. I would be pleased to respond to
    any questions.
        [The prepared statement of Dr. Pace follows:]

                        Prepared Statement of Scott Pace

        Mr. Chairman and Members of the Subcommittee, thank you for the
    opportunity to appear today to review the findings and recommendations
    of NASA's report to Congress in response to the NASA Authorization Act
    of 2005 (P.L. 109-155). Below, I have addressed the questions posed by
    this Subcommittee in your invitation to testify.

    Question #1: What were the principal findings and recommendations of
    NASA's Near-Earth Object Survey and Deflection Analysis of
    Alternatives: Report to Congress, March 2007, and what was the basis
    for those findings and recommendations?

        The principal findings were the result of a study team, led by
    NASA's Office of Program Analysis and Evaluation (PA&E) that conducted
    an analysis of alternatives with inputs from several other U.S.
    Government agencies, international organizations, and representatives
    of private organizations. The team developed a range of possible
    options from public and private sources and then analyzed their
    capabilities and levels of performance including costs, development
    schedules, and technical risks. In order to meet the congressional goal
    of completing the survey by 2020, the study team assumed primary
    project elements would have started their development by October 1,
    2007.
        NASA recommended that the existing ``Spaceguard Survey'' program
    continue as currently planned, and that NASA would also take advantage
    of opportunities using potential dual-use telescopes\1\ and
    spacecraft--and partner with other agencies as feasible--to make
    progress toward achieving the legislative goal of discovering 90
    percent of all potentially hazardous objects 140 meters in mean
    diameter and greater. However, due to budget constraints, NASA cannot
    initiate a new program beyond the Spaceguard Survey program at this
    time.
    ---------------------------------------------------------------------------
        \1\ The proposed Large Synoptic Survey Telescope (LSST) and
    Panoramic Survey Telescope And the Rapid Response System (Pan-STARRS)
    present possible future opportunities, if they are funded by other
    agencies. Another possible opportunity would be the Lowell Discovery
    Channel Telescope (DCT), but its contribution would be less than LSST
    or Pan-STARRS.
    ---------------------------------------------------------------------------
        NASA would be pleased to implement a more aggressive NEO program if
    so directed by the President and Congress. However, given the
    constrained resources and strategic objectives the Agency has already
    been tasked with, NASA cannot place a new NEO program above current
    scientific and exploration missions.
        For ease of following the findings and recommendations, simplified
    definitions are as follows:

              ``Detection'' is the act of finding the objects;

              ``Tracking'' is the act of determining their orbits;

              ``Characterization'' is the act of determining their
            physical properties;

              ``Cataloging'' is the act of maintaining a data base
            of the orbits and physical properties of known objects and
            predicting potential impacts with the Earth; and

              ``Mitigation'' is the act of deflecting, destroying,
            or reducing the impact consequences of a specific object that
            is predicted to strike the Earth.

    Key Findings for the Survey Program

              The goal of the Survey Program should be modified to
            detect, track, catalogue, and characterize, by the end of 2020,
            90 percent of all Potentially Hazardous Objects (PHOs) greater
            than 140 meters whose orbits pass within 0.05 AU (Astronomical
            Units) of the Earth's orbit (as opposed to surveying for all
            NEOs).

              The Agency could achieve the specified goal of
            surveying for 90 percent of the potentially hazardous NEOs by
            the end of 2020 by partnering with other government agencies on
            potential future optical ground-based observatories and
            building a dedicated NE0 survey asset, assuming the partners'
            potential ground assets come online by 2010 and 2014, and a
            dedicated asset by 2015.

              Together, the two observatories potentially to be
            developed by other government agencies could complete 83
            percent of the survey by 2020 if observing time at these
            observatories is shared with NASA's NE0 Survey Program.

              New space-based infrared systems, combined with
            shared ground-based assets, could reduce the overall time to
            reach the 90 percent goal by at least three years. Space
            systems have additional benefits as well as costs and risks
            compared to ground-based alternatives.

              Radar systems cannot contribute to the search for
            potentially hazardous objects, but may be used to rapidly
            refine tracking and to determine object sizes for a few NEOs of
            potentially high interest.

              Determining a NEO's mass and orbit is required to
            determine whether it represents a potential threat and to
            provide required information for most alternatives to mitigate
            such a threat. Beyond these parameters, characterization
            requirements and capabilities are tied directly to the
            mitigation strategy selected.

    Key Findings for Diverting a Potentially Hazardous Object (PHO)

        The study team assessed a series of approaches that could be used
    to divert a NEO potentially on a collision course with Earth. Nuclear
    explosives, as well as non-nuclear options, were assessed.

              Nuclear standoff explosions are assessed to be 10-100
            times more effective than the non-nuclear alternatives analyzed
            in this study. Other techniques involving the surface or
            subsurface use of nuclear explosives may be more efficient, but
            they run an increased risk of fracturing the target NEO. They
            also carry higher development and operations risks.

              Non-nuclear kinetic impactors are the most mature
            approach and could be used in some deflection/mitigation
            scenarios, especially for NEOs that consist of a single small,
            solid body.

              ``Slow push'' mitigation techniques are the most
            expensive, have the lowest level of technical readiness, and
            their ability to both travel to and divert a threatening NEO
            would be limited unless mission durations of many years to
            decades are possible.

              30-80 percent of potentially hazardous NEOs are in
            orbits that are beyond the capability of current or planned
            launch systems. Therefore, planetary gravity assist swing-by
            trajectories or on-orbit assembly of modular propulsion systems
            may be needed to augment launch vehicle performance, if these
            objects need to be deflected.

    Question #2: How were the cost estimates and technical options
    contained in the report arrived at, and was any independent assessment
    of the cost estimates and technical options conducted?

    Technical Options

        The technical options contained in the report were developed
    through a systematic exploration of the trade space for feasible
    alternatives, followed by a conceptual design of selected options.
    Concepts were selected to represent the available range of cost,
    performance, and acceptable technical risk to complete the detection,
    tracking, cataloguing, and characterization missions. Concepts were
    based on historical and existing projects and on white papers presented
    at a NASA-sponsored workshop of national experts.
        Trade trees were developed to describe the technical options. The
    detection and tracking trade tree consisted of existing and new ground-
    and space-based observatories operating in the visible and infrared
    spectra; ground based radars were considered for tracking. The
    characterization trade tree contained existing, proposed, and new
    remote and in-situ observing assets. Cataloguing considered a range of
    operations and data management options based on historical, proposed,
    and new information systems.

    Cost Estimates

        Life cycle costs were calculated as the total architecture cost in
    fiscal year 2006 billions of dollars including development, production,
    deployment, and operation of the alternatives. Life cycle costs for the
    detection, tracking, and data management options were calculated both
    for a fixed period (through 2020) and until the objective of
    cataloguing 90 percent of specified threats was complete. For some
    options that rely on existing systems or available technology,
    operational costs were much higher than the development costs over the
    15-20 year life cycle. In order to meet the Congressional goal of
    completing the survey by 2020, the study team assumed primary project
    elements would have started their development by October 1, 2007.
        For space-based systems, the total life cycle costs included
    estimated costs for program management, systems engineering, mission
    assurance, launch vehicle, spacecraft, scientific instruments, mission
    specific ground data systems, mission operations, and data analysis.
    Ground-based systems included the cost of development, production, and
    operations. Operations costs were calculated over either the survey
    period for detection, tracking, and cataloguing missions or the
    predicted duration of characterization missions.
        The cost estimates for the space vehicles relied on multiple
    methods including historical analogies and prior cost-estimating
    experience. Cost-risk analyses were performed using these data as
    inputs and assumed that every cost element could be represented by
    statistical characteristics such as mean, standard deviation, and mode.
    A cumulative probability distribution of total cost was generated for
    this analysis by combining cost distributions from the different cost
    elements, and costs were estimated at the 65 percent cost confidence
    level when applicable. Programmatic costs were based on historical
    actual costs and applied as a percentage of the space vehicle costs.
    Launch vehicle costs were based on recent, publicly released estimates
    for commercial launch vehicles.
        Ground-based observatory costs were based on reported expenses for
    currently operating systems or based on estimates for systems currently
    in development. For several ground based options, concepts of
    operations postulated utilizing (sharing) data that would be collected
    on existing or planned systems without materially affecting the primary
    mission of these systems. For these systems, it was assumed that the
    NEO program would fund only a small portion (or none) of the
    development costs, but that an equitable portion of the annual
    operations costs would be funded by NASA. In cases where the ground
    based systems were expected to be copies of systems that are currently
    in development, only the production and operation costs of the NASA-
    acquired systems were considered--substantially reducing their
    development costs and cost-risk.
        Although multiple cost-estimating methodologies, databases, and
    organizations were used, truly independent cost estimates were not
    generated as these are typically not within the scope of a conceptual,
    architecture-level study. Likewise, assessments of the technical
    options were carried out using an experienced team of personnel from
    several organizations, but fully separate evaluations of the concepts
    were not performed.

    Question #3: What is the ``recommended option and proposed budget to
    carry out the Survey program pursuant to the recommended option,'' as
    called for in Sec. 321(d)(2)?

        NASA recommended that the existing ``Spaceguard Survey'' program
    continue as currently planned, and that NASA would also take advantage
    of opportunities using potential dual-use telescopes\2\ and spacecraft-
    and partner with other agencies as feasible-to make progress toward
    achieving the legislative goal of discovering 90 percent of all
    potentially hazardous objects 140 meters and greater.
    ---------------------------------------------------------------------------
        \2\ The proposed Large Synoptic Survey Telescope (LSST) and
    Panoramic Survey Telescope And the Rapid Response System (Pan-STARRS)
    represent possible future opportunities, if they are funded by other
    agencies. Another possible opportunity would be the Lowell Discovery
    Channel Telescope (DCT), but its contribution would be less than LSST
    or Pan-STARRS.
    ---------------------------------------------------------------------------
        The goal of finding 90 percent of potentially hazardous objects 140
    meters and larger is one to two orders of magnitude more technically
    challenging than the Spaceguard mission. To reach this goal within 10-
    15 years requires at least one new dedicated ground or space
    observatory.
        Cataloging the number of total number of objects--approximately
    100,000--at the rate they would be discovered, which is between 30 and
    50 per day, requires a new tracking and data management infrastructure
    whose ongoing operations may constitute a sizable portion of total
    costs.
        A delay (e.g., 5-10 years) in achieving the legislative goal
    carries little additional risk when the impact interval for 140m
    objects is about once every 5,000 years. This rate of impacts also
    indicates that the system may need to operate (searching and tracking)
    for an extended period before identifying a credible threat. There are
    three epochs to the problem of detection and tracking:

              Now: We know where few 140m objects are and when/if
            they will impact.

              Initial 10-20 years of the survey: Average warning
            time will rise, unwarned impact risk gradually decline. Decades
            of warning become likely.

              Steady-state: After 10-20 years of the survey,
            unwarned impacts of 140m objects would be highly unlikely.
            Centuries of warning become possible.

        Currently, NASA carries out the ``Spaceguard Survey'' to find NEOs
    greater than 1 kilometer in diameter, and this program is currently
    budgeted at $4.1 million per year for FY 2006 through FY 2012. We also
    have benefited from knowledge gained in our Discovery space mission
    series, such as the Near-Earth Asteroid Rendezvous (NEAR), Deep Impact,
    and Stardust missions that have expanded our knowledge of near-Earth
    asteroids and comets. Participation by NASA in international
    collaborations such as Japan's Hayabusa mission to the NEO ``Itokawa''
    also greatly benefited our understanding of these objects. NASA's Dawn
    mission, launched on September 27, 2007, will increase our
    understanding of the two largest known main belt asteroids, Ceres and
    Vesta, between the planets Mars and Jupiter. NASA conducts survey
    programs on many celestial objects--the existing Spaceguard program for
    NEOs, surveys for Kuiper Belt Objects, the search for extra-solar
    planets, and other objects of interest such as black holes to
    understand the origins of our universe. The science community could
    propose such a NEO survey mission under the competitively-selected
    Discovery program.
        NASA also identified an exemplar NEO Survey Program and estimates
    for its architectural costs that, if funded, could have achieved the
    specified goal of surveying 90 percent of the PHOs by the end of 2020
    by constructing or funding a dedicated survey asset combined with NASA
    partnerships with other government agencies on potential future optical
    ground-based observatories: the Panoramic Survey Telescope and Rapid
    Response System (Pan-STARRS-4 or PS4) and the Large Synoptic Survey
    Telescope (LSST). Details of the exemplar program were provided in
    NASA's report. Note that budget estimates in the report are rough
    ``architecture costs'' and would require more rigorous analysis before
    a program could be assessed for implementation.

    Question #4: Will NASA's current NEO program satisfy the requirement
    established in Sec. 321(d)(1) of the NASA Authorization Act of 2005,
    and if not, what is NASA's plan for satisfying that requirement?

        The current NASA NEO ``Spaceguard Survey'' program, without any
    augmentation, would not be able to satisfy the requirements outlined in
    section 321(d)(1) of the NASA Authorization Act for 2005. The
    requirements for the Spaceguard Survey program are to find only NEOs
    greater than one kilometer in diameter, and its funding is currently
    budgeted at $4.1 million per year. NASA estimates that the current
    program, if continued without major augmentation, would detect 14
    percent of the 140 meters or larger potentially hazardous objects by
    the end of 2020. However, NASA is initiating plans to use other survey
    systems to increase the survey's detection sensitivity and rates. For
    example, NASA has begun providing funds to the Air Force Panoramic
    Survey Telescope and Rapid Response System (Pan-STARRS) project so that
    it will be capable of providing data on NEO detections after it starts
    operations on its first telescope in the next year. If the Air Force
    continues to fund this project to its intended four telescope
    configuration by 2010, this system alone could discover over 70 percent
    of the potentially hazardous objects larger than 140 meters by 2020.
        NASA recommended that the existing ``Spaceguard Survey'' program
    continue as currently planned, and that NASA would also take advantage
    of opportunities using potential dual-use telescopes and spacecraft--
    and partner with other agencies as feasible--to make progress toward
    achieving the legislative goal of discovering 90 percent of all
    potentially hazardous objects 140 meters and greater.
        NASA would be pleased to implement a more aggressive NEO program,
    if so directed by the President and Congress. However, given the
    constrained resources and strategic objectives the Agency has already
    been tasked with, NASA cannot place a new NEO program above current
    scientific and exploration missions.

    Question #5: How is progress on meeting the requirements of Section 321
    being measured and monitored?

        Survey performance is tracked continuously by the NEO Program
    Office at JPL, and reported monthly on NASA's NEO Program website at
    http://neo.jpl.nasa.gov/stats. This database shows the performance of
    each survey team and reports the number of NEOs, including Earth
    approaching comets, found each month by orbit and size (larger or
    smaller than one kilometer) class. It also breaks out the objects which
    are potentially hazardous by size class. Specific orbit and estimated
    size information for each discovered NEO can also been found on the
    website, as well as probability of impact statistics for Potentially
    Hazardous Objects.
        The discovery statistics information is rolled up each year and
    reported by the Science Mission Directorate as part of our Government
    Performance Reporting Act (GPRA) submittal.
        In closing, NASA recommends that the existing ``Safeguard Survey''
    program continue, as planned, and that the Agency take advantage of
    opportunities using potential dual-use telescopes and spacecraft, as
    well as partner with other agencies, to make progress toward achieving
    the legislative goal.
        Mr. Chairman, I would be pleased to respond to any questions you or
    the other Members of the Subcommittee may have.

                            Biography for Scott Pace

        Scott Pace is the Associate Administrator for Program Analysis and
    Evaluation at NASA. In this capacity, he is responsible for providing
    objective studies and analyses in support of policy, program, and
    budget decisions by the NASA Administrator. He previously served as
    Chief Technologist for Space Communications in NASA's Office of Space
    Operations where he was responsible for advising senior NASA management
    on issues related to space-based information systems. He participated
    in the negotiations that resulted in the 2004 GPS-Galileo Agreement
    between the United States and the European Commission. Pace also
    previously served as the Deputy Chief of Staff to NASA Administrator
    Sean O'Keefe. His primary areas of responsibility included oversight of
    the President's Management Agenda in Human Capital, Competitive
    Sourcing, Expanding e-Government, Financial Management, and Integrating
    Budget and Performance.
        Prior to NASA, Pace was the Assistant Director for Space and
    Aeronautics in the White House Office of Science and Technology Policy
    (OSTP). There he was responsible for space and aviation-related issues
    and coordination of civil and commercial space issues through the Space
    Policy Coordinating Committee of the National Security Council. Pace
    served on the Bush-Cheney Transition Team for NASA and the National
    Science Foundation.
        Prior to his White House appointment, Pace worked for the RAND
    Corporation's Science and Technology Policy Institute (STPI)--a
    federally funded research and development center for the Office of
    Science and Technology Policy. In addition to his extensive research
    into space policy, technology policy, and international competitiveness
    at RAND, Pace also was a key member of a successful international
    effort to preserve radio navigation satellite spectrum at the 1997
    World Radiocommunication Conference (WRC97) and the addition of new
    spectrum for satellite navigation at WRC-2000. He also was a member of
    the Department of Defense Senior Review Group on Commercial Remote
    Sensing and the National Research Council's Committee on Earth
    Sciences.
        From 1990 to 1993, Pace served as the Deputy Director and Acting
    Director of the Office of Space Commerce (OSC), in the Office of the
    Deputy Secretary of the Department of Commerce. Among his many
    responsibilities at OSC, Pace coordinated space policy issues across
    the Department and participated in efforts affecting export controls
    for space technologies; space trade negotiations with Japan, Russia,
    China, and Europe; the licensing process for private remote sensing
    systems; missile proliferation; and the U.S. space industrial base.
        Pace received a Bachelor of science degree in physics from Harvey
    Mudd College in 1980; Master of science degrees in aeronautics and
    astronautics and technology and policy from the Massachusetts Institute
    of Technology in 1982; and a doctorate in policy analysis from the RAND
    Graduate School in 1989. His dissertation was entitled ``U.S. Access to
    Space: Launch Vehicle Choices for 1990-2010.''

        Chairman Udall. Thank you, Dr. Pace. Dr. Yeomans.

    STATEMENT OF DR. DONALD K. YEOMANS, MANAGER, NEAR-EARTH OBJECT
               PROGRAM OFFICE, JET PROPULSION LABORATORY

        Dr. Yeomans. Mr. Chairman and Members of the Subcommittee,
    thank you for the opportunity to appear today.
        Chairman Udall. Dr. Yeomans, I think you should turn on
    your microphone, if you can.
        Dr. Yeomans. Thank you for the opportunity to appear today
    to discuss the potential threats of Near-Earth Objects,
    progress toward meeting the discovery goal articulated in the
    NASA Authorization Act of 2005, the role of the Arecibo
    Planetary Radar within the Near-Earth Object Program, and the
    response options available if a Near-Earth Object is found to
    be on an Earth-threatening trajectory.
        Near-Earth objects are comets and asteroids that can pass
    within about 45 million kilometers of the Earth's orbit. While
    some showy naked eye comets may occasionally pass close to
    Earth, it is the difficult to find, but the far more numerous
    asteroids are of the most concern in near-Earth space today.
    About one-fifth of the near-Earth asteroids can approach the
    Earth's orbit even closer, to within seven and a half million
    kilometers, and these so-called potentially hazardous asteroids
    are of most concern for near-term hazard avoidance.
        As part of the NASA Authorization Act of 2005, NASA was
    asked to consider options for extending the search down to
    objects as small as 140 meters in diameter, and to find and
    catalog them within 15 years of the Act becoming law. By
    finding and cataloging 90 percent of this population of
    potentially hazardous asteroids, the statistical or actuarial
    risk to Earth from potentially hazardous asteroids of all sizes
    would be reduced by 99 percent from pre-survey levels. We can
    speak of risk reduction in this case, because once an object is
    discovered and cataloged, its future motion can accurately be
    predicted, and in the unlikely case where it does threaten
    Earth, there would be sufficient time to deflect it, thus
    saving the enormous costs due to fatalities and/or
    infrastructure damage.
        According to a 2003 NASA Near-Earth Object science
    definition team study that undertook a cost-benefit analysis
    for the discovery of potentially hazardous asteroids, the risk
    reduction accruing from this next generation potentially
    hazardous asteroid search would pay for itself in the first
    year of operations.
        While an impact by a 140 meter sized object would not
    generate global physical consequences, its impact energy would
    still be about 100 megatons of TNT explosive, and the
    likelihood of one of these impacts is 100 times greater than an
    impact by one of the less numerous one kilometer size
    potentially hazardous asteroids.
        With regard to the uncertainty associated with threats from
    potentially hazardous asteroids, the largest factor, by far, is
    the large number of undiscovered objects in the size ranges
    that are small enough to be very numerous, yet large enough to
    easily penetrate the Earth's atmosphere. For example, we have
    only discovered about four percent of the 20,000 potentially
    hazardous asteroids larger than 140 meters, and less than one
    percent of the 200,000 objects larger than 50 meters.
        The solution to this uncertainty is to continue and
    hopefully accelerate the search for potentially hazardous
    asteroids. Once we find the vast majority of them, they can be
    tracked, cataloged, and then ruled out or in as threats during
    the next 100 years or so.
        The current NASA Near-Earth Object goal is focused upon the
    discovery and tracking of objects one kilometer in diameter and
    larger. It is not realistic to expect the current survey
    program, with its modestly sized telescopes, to efficiently
    find 140 meter sized objects that are nearly 50 times fainter
    compared to the one kilometer sized objects at the same
    distance and with the same reflectivity.
        Because all potentially hazardous asteroids do eventually
    come very close to the Earth, the current ongoing surveys could
    complete the goal outlined in the 2005 NASA Authorization Act,
    but it would likely take over a century to do so. We simply
    cannot afford to wait that long.
        At least two next generation ground-based wide-field search
    telescope surveys are in development. Pan-STARRS is under
    development at the University of Hawaii, with Air Force
    funding, and will have one of its 1.8 meter telescopes
    operational in Hawaii in early 2008. If the planned four
    telescope version of Pan-STARRS is completed by 2010, it could
    help reach the goal by about 2040.
        Likewise, the 8.4 meter aperture LSST telescope that is
    under development with funding from NSF, DOE, and other
    partners, could help reach the goal by about 2034, if it began
    operation in 2014.
        If we assume that both the Pan-STARRS four telescope system
    and the LSST operate in their planned shared mode, which
    includes many observations unrelated to potentially hazardous
    asteroids, then the goal could be reached by about 2026. The
    potentially hazardous asteroid discovery rate could be
    increased beyond the results shown in the NASA report, if the
    observing times and sequences of Pan-STARRS and LSST were
    optimized for potentially hazardous asteroid observations.
        Both positional data for potentially hazardous asteroid
    orbit determination and trajectory predictions are based upon
    optical, plane-of-sky observations. Because the radars provide
    line of sight, velocity, and range information to about one
    millimeter per second and 10 meter accuracy levels, this data,
    when used in conjunction with the optical data, provide a
    secure orbit and trajectory far more rapidly than if only
    optical data are available. With only a limited amount of
    optical data to work with, the orbit of a newly discovered
    potentially hazardous asteroid is often not accurate enough to
    immediately rule out a future Earth impact.
        However, with radar data in hand, the orbit of a newly
    discovered potentially hazardous asteroid can be quickly and
    more precisely determined, its motion accurately projected far
    into the future, and future impact possibilities can usually be
    quickly ruled out. Likewise, in the rare situation when an
    object is actually on an Earth-impacting trajectory, radar
    observations will be critical in quickly identifying this case.
        A number of existing technologies can deflect an Earth-
    threatening asteroid if there is time. The primary goal of the
    potentially hazardous asteroid survey programs is to discover
    them early and provide the necessary time. An asteroid that is
    predicted to hit Earth would require a change in its velocity
    of only three millimeters per second, if this impulse were
    applied 20 years in advance of the impact itself. The key to a
    successful deflection is having sufficient time to carry it
    out, whether it is a slow, gentle drag of a gravity tractor, or
    the more impulsive shove from an impacting spacecraft or
    explosive device. In either case, the verification process will
    be required to ensure the deflection maneuver was successful,
    and to ensure the object's subsequent motion would not put it
    on yet another Earth-impacting trajectory.
        While suitable deflection technologies exist, none of them
    can be effective if we are taken by surprise. It is the
    aggressive survey efforts and robust radar systems that must
    ensure that the vast majority of potentially hazardous objects
    are discovered and tracked well in advance of any Earth-
    threatening encounters.
        The first three steps in any asteroid mitigation process
    are find them early, find them early, and find them early.
        Thank you.
        [The prepared statement of Dr. Yeomans follows:]

                    Prepared Statement of Donald K. Yeomans

        Mr. Chairman and Members of the Subcommittee, thank you for the
    opportunity to appear today to discuss the potential threats of near-
    Earth objects (NEOs), our progress toward meeting the discovery goal
    articulated in the NASA Authorization Act of 2005, the role of the
    Arecibo planetary radar within the NEO program and the response options
    available if a NEO is found to be on an Earth impacting trajectory.

    The Near-Earth Object Population: When the Earth was young, frequent
    collisions of comets and asteroids likely delivered much of the water
    and carbon-based molecules that allowed life to form, and once life did
    form, subsequent collisions may have punctuated the evolutionary
    process and allowed only the most adaptable species to progress
    further. We may owe our very existence atop the world's food chain to
    these objects. As the Earth's closest neighbors (some pass within the
    Moon's distance), these icy comets and rocky asteroids have been termed
    near-Earth objects. Their proximity to Earth presents an opportunity to
    utilize their vast metal, mineral and water ice resources for future
    space structures and habitats. Their water resources can be broken down
    into hydrogen and oxygen--the most efficient form of rocket fuel. These
    near-Earth objects may one day be the resources, fueling stations and
    watering holes for human interplanetary exploration. While these
    objects are of extraordinary scientific interest, likely enabled the
    origin of life itself, and may loom large for the future development of
    space exploration, their proximity to Earth also presents a potential
    horrific threat should a relatively large near-Earth object once again
    strike Earth without warning.

    Potentially Hazardous Asteroids: Near-Earth objects are comets and
    asteroids that can pass within 45 million kilometers of the Earth's
    orbit. While some showy, naked-eye comets may occasionally pass close
    to Earth, it is the difficult to find (but far more numerous asteroids)
    that are of most concern in near-Earth space today. About one fifth of
    the near-Earth asteroids can approach the Earth's orbit even closer (to
    within 7.5 million kilometers), and these so-called potentially
    hazardous asteroids (PHAs) are of most concern for near-term hazard
    avoidance.
        Celestial debris hits the Earth all the time, but the vast majority
    of it is so small that it does not survive passage through the Earth's
    atmosphere. The debris is created over millions of years, as asteroids
    inevitably run into each other, producing smaller fragments, which
    themselves collide yielding even more debris. Over time, the fragments
    and debris spread out, and some of it migrates into Earth approaching
    orbits. The Earth is pummeled with more than 100 tons of impacting
    material each day but almost all of it is far too small to cause
    anything other than a harmless meteor, or shooting star, or the
    occasional fireball event. Larger objects are less numerous than
    smaller objects and hit the Earth less often. While a basketball-sized
    object strikes the Earth's atmosphere daily, larger car-sized impactors
    hit only a few times each year, and even these generally break up into
    smaller pieces as they streak through the atmosphere. Occasionally a
    fragment of a larger impactor will reach the Earth's surface--one such
    hit may have occurred less than two months ago when a reported asteroid
    fragment perhaps one meter in diameter struck in southern Peru creating
    a 13-meter crater near Lake Titicaca.
        Larger impactors with diameters in the 50 to 140 meter range, while
    they do not usually impact the ground, can result in damaging air
    blasts that cause significant destruction. For example, on June 30,
    1908, an impactor with a diameter of about 50 meters detonated over the
    Tunguska region of Siberia and leveled trees for 2,000 square
    kilometers. Its impact energy has been estimated at about 10 million
    tons of TNT explosives (10 megatons or 10 MT), comparable in energy
    with a modern nuclear weapon. Roughly speaking, PHAs that have
    diameters larger than 140m can punch through the Earth's atmosphere and
    cause regional damage if they strike land or create a harmful tsunami
    should they impact into an ocean. There are thought to be about 20,000
    PHAs in this size range, each with a potential impact energy of 100 MT
    or more. On average, one of these objects would be expected to strike
    Earth every 5,000 years and therefore would have a one percent
    probability of impact in the next 50 years. Although their mean impact
    frequency would be about once every 500,000 years, PHAs larger than a
    kilometer in diameter could cause global consequences due to not only
    the extraordinary blast itself (50,000 MT) but also the dust and debris
    thrown into the air, and the subsequent firestorms and acid rain. The
    extinction of the dinosaurs and a sizable fraction of the Earth's other
    species some 65 million years ago is thought to be due to an impactor
    with a diameter of about 10 kilometers that created an impact energy of
    as much as 50 million MT. Over very long time intervals, PHAs with
    diameters greater than one kilometer are statistically the most
    dangerous objects because their impacts would cause global
    consequences.

    NASA Responses to the PHA Issues: In 1998, before the Subcommittee on
    Space and Aeronautics, a NASA representative outlined the goal to
    discover and catalog 90 percent of the NEOs larger than one kilometer
    by the end of 2008. There are currently thought to be over 900 of these
    objects, and about 80 percent of them have already been found and
    cataloged. Roughly the same percentage of PHAs in this size range has
    also been found. When this goal has been reached, 90 percent of the
    global risk from PHAs would be retired. Almost all of these discoveries
    have come by way of NASA supported search programs.
        As part of the NASA Authorization Act of 2005, NASA was asked to
    consider options for extending the search down to objects as small as
    140 meters in diameter, and to find and catalog them within 15 years of
    the Act becoming law (i.e., by the end of 2020). By finding and
    cataloging 90 percent of this population of PHAs, the statistical or
    actuarial risk to Earth from PHAs of all sizes would be reduced by 99
    percent from pre-survey levels. We can speak of risk reduction in this
    case because once an object is discovered and cataloged, its future
    motion can accurately be predicted and, in the unlikely case where it
    does threaten Earth, there would be sufficient time to deflect it, thus
    saving the enormous costs due to fatalities and/or infrastructure
    damage. According to a 2003 NASA NEO Science Definition Team study that
    undertook a cost/benefit analysis for the discovery of PHAs, the risk
    reduction accruing from this next generation PHA search would pay for
    itself in the first year of operations. While an impact by a 140 meter-
    sized object would not generate global physical consequences, its
    impact energy would still be about 100 MT, and the likelihood of one of
    these impacts is 100 times greater than an impact by one of the less
    numerous one kilometer-sized PHAs.
        With regard to the uncertainty associated with threats from PHAs,
    the largest factor, by far, is the large number of undiscovered objects
    in the size ranges that are small enough to be very numerous but large
    enough to easily penetrate the Earth's atmosphere. For example, we have
    discovered only about four percent of the 20,000 PHAs larger than 140
    meters and less than one percent of the 200,000 objects larger than 50
    meters. The solution to this uncertainty is to continue and hopefully
    accelerate the search for PHAs. Once we find the vast majority of them,
    they can be tracked, cataloged and then ruled out (or in) as threats
    during the next 100 years or so. This process can continue year after
    year so the window of safety is always at least 100 years. There are
    other, less significant, uncertainties dealing with the refinement of a
    particular object's size, mass and structure as well as the dynamical
    model that is used to accurately predict the object's motion over 100
    year time scales. For example, over long time intervals, the minute
    pressure of sunlight and its thermal re-radiation can significantly
    affect a PHA's motion. For a select number of Earth approaching
    objects, we will need the use of the planetary radars, or possibly
    rendezvous spacecraft missions, to better understand their sizes,
    shapes, masses, surface properties, and possible binary natures.

    The Next Generation of Search: As noted, the current NASA NEO goal is
    focused upon the discovery and tracking of objects one kilometer in
    diameter and larger. It is not realistic to expect the current survey
    program, with its modestly sized telescopes, to efficiently find the
    140 meter-sized objects that are nearly 50 times fainter compared to a
    one kilometer-sized object at the same distance and with the same
    reflectivity. Because all PHAs do eventually come very close to the
    Earth, the current ongoing surveys could complete the goal outlined in
    the 2005 NASA Authorization Act but it would likely take over a century
    to do so. We cannot afford to wait that long.
        In the report to Congress requested by the 2005 NASA Authorization
    Act, several options were outlined, both ground-based and space-based,
    that could meet the goal of finding 90 percent of the PHAs larger than
    140 meters by the end of 2020. For example, a one-meter aperture
    infrared telescope in a heliocentric orbit near Venus could do the job
    three years early. Within this report, NASA noted that it did not have
    the resources to carry out a survey option that would meet the 2020
    deadline set by the 2005 Act and that, in an attempt to achieve the
    legislative goal by the end of 2020, it would seek to continue the
    current survey programs and look for opportunities to use dual use
    telescope facilities and spacecraft along with partnering with other
    agencies as feasible.
        At least two next-generation, ground-based, wide-field search
    telescope surveys are in development. The Panoramic Survey Telescope
    and Rapid Response System (Pan-STARRS), under development at the
    University of Hawaii with Air Force funding, will have one of its four
    1.8 meter telescopes operational in Hawaii in early 2008. If the
    planned, four telescope version of Pan-STARRS is completed by 2010, it
    could help reach the goal by about 2040. Likewise the 8.4 meter
    aperture Large Synoptic Survey Telescope (LSST) that is under
    development with funding from NSF, DOE and other partners, could help
    reach the goal by about 2034 if it began operation in 2014. If we
    assume that both the Pan-STARRS four telescope system and the LSST
    operate in their planned shared modes, which includes many observations
    unrelated to PHAs, then the goal could be reached by about 2026. The
    PHA discovery rate could be increased beyond the results shown in the
    NASA response to the 2005 Act if the observing time and sequences of
    Pan-STARRS and LSST were optimized for PHA observations.
        In terms of actual discoveries of new PHAs, there has been little
    success beyond the survey programs supported by NASA. However, the
    international community, including many sophisticated amateur
    astronomers, is very active in providing the follow-up observations
    necessary to secure an object's orbit once it has been found. The
    NEODyS program in Pisa, Italy works closely with, but independent of,
    the NEO Program Office at JPL to compute impact probabilities for
    predicted Earth close approaches for at least 100 years into the
    future. It is also encouraging to note the activities of a NEO Action
    Team within the UN Committee on the Peaceful Uses of Outer Space
    (COPUOS) includes an effort to encourage more international efforts on
    the NEO issues.

    The importance of Radar Observations: There are only two planetary
    radars in existence (and no alternatives) that can routinely observe
    close Earth approaching asteroids, and both of them are critically
    important for investigating the nature of these objects and for rapidly
    refining their trajectories. The 70-meter Goldstone antenna in
    California's Mojave desert is fully steerable, can track an asteroid
    and can cover large regions of sky while the larger 305-meter Arecibo
    antenna in Puerto Rico has twice the range but only observes within a
    40-degree zone centered on the overhead position (20 degrees on either
    side of zenith). The capabilities of these two telescope complement one
    another and often a significantly better and longer set of observations
    can be achieved using both radars on a close approaching target
    asteroid.
        Most positional data for PHA orbit determination and trajectory
    predictions are based upon optical, plane-of-sky observations. Because
    the radars provide line-of-sight velocity and range information
    accurate to about the one mm/s and 10 meter levels, these data when
    used in conjunction with the optical data provide a secure orbit and
    trajectory far more rapidly than if only optical data are available.
    With only a limited amount of optical data to work with, the orbit of a
    newly discovered PHA is often not accurate enough to immediately rule
    out a future Earth impact. However, with radar data in hand, the orbit
    of a newly discovered PHA can be quickly and more precisely determined,
    its motion accurately projected far into the future and future impact
    possibilities can usually be quickly ruled out. Likewise, in the rare
    situation when an object is actually on an Earth threatening
    trajectory, radar observations will be critical in quickly identifying
    this case.
        Unfortunately the Arecibo radar program is not funded by the NSF
    beyond FY 2007 and the planetary science community is in danger of
    losing one of its instrumental crown jewels. As a measure of this radar
    facility's importance, note that 65 percent of all radar experiments to
    characterize near-Earth asteroids were performed at Arecibo, 47 percent
    of all binary near-Earth asteroids were discovered at Arecibo and 85
    percent of the near-Earth asteroids with the critical astrometric radar
    data for orbit improvement have data from Arecibo. All of this was
    accomplished with only five percent of this instrument's time. The
    superior sensitivity of the giant Arecibo radar can determine the
    sizes, shapes, rotation characteristics, surface characteristics and
    binary nature for many PHAs. All of these physical characteristics are
    important criteria to understand before a deflection mission is
    considered. Radar observations are responsible for the best physical
    characterization of any PHA as large as a kilometer (i.e., the binary
    asteroid 1999 KW4). Radar observations reduce a PHA's orbit
    uncertainties quickly and dramatically so that future impact
    possibilities can be quickly knocked down thus reducing the odds that
    we will need to invest in a spacecraft investigation to characterize
    the PHA's nature in preparation for a precautionary deflection mission.
    Thus the relatively modest costs of maintaining the Arecibo radar in a
    robust state could prevent the future need for 100's of millions of
    dollars per case for spacecraft reconnaissance of an object to
    determine whether or not it is an actual threat.

    What Should be Done in the Event of an identified NEO Threat? A number
    of existing technologies can deflect an Earth threatening asteroid--if
    there is time. The primary goal of the PHA survey programs is to
    discover them early and provide the necessary time. An asteroid that is
    predicted to hit Earth might require a change in its velocity of only
    three millimeters per second if this impulse were applied twenty years
    in advance of the impact. The key to a successful deflection is having
    sufficient time to carry it out, whether it is the slow, gentle drag of
    a gravity tractor or a more impulsive shove from an impacting
    spacecraft or explosive device. In either case, a verification process
    would be required to ensure the deflection maneuver was successful and
    to ensure the object's subsequent motion would not put it on yet
    another Earth impacting trajectory. While suitable deflection
    technologies exist, none of them can be effective if we are taken by
    surprise. It is the aggressive survey efforts and robust planetary
    radars that must ensure that the vast majority of potentially hazardous
    objects are discovered and tracked well in advance of any Earth
    threatening encounters. The first three steps in any asteroid
    mitigation process are: Find them early, find them early, and find them
    early!

                        Biography for Donald K. Yeomans

        At the Jet Propulsion Laboratory in Pasadena California, Donald K.
    Yeomans is a Senior Research Scientist, supervisor of the Solar System
    Dynamics Group, and manager of NASA's Near-Earth Object Program Office.
    His group is responsible for providing position predictions for the
    solar system's planets, natural satellites, comets and asteroids. For
    the comets and asteroids that can approach the Earth, his group
    monitors their motions and provides predictions and impact
    probabilities for future Earth encounters.
        Dr. Yeomans was the Radio Science team chief for NASA's Near-Earth
    Asteroid Rendezvous (NEAR) mission. He is currently the NASA Project
    Scientist for the Joint Japanese and U.S. mission to land upon, and
    return a sample from, a near-Earth asteroid (Hayabusa) and he was a
    scientific investigator on NASA's Deep Impact mission that successfully
    impacted comet Tempel 1 in July 2005. He provided the accurate
    predictions that led to the recovery of comet Halley at Palomar
    Observatory on October 16, 1982 and allowed the discovery of 164 BC
    Babylonian observations of comet Halley on clay tablets in the British
    Museum.
        He is a graduate of Middlebury College in Vermont and received his
    doctorate degree in astronomy from the University of Maryland in 1970.
    He has written numerous technical papers and four books on comets and
    asteroids. He has been awarded 15 significant achievement awards by
    NASA including an Exceptional Service Medal and a Space Act Award. To
    honor his work in planetary science, asteroid 2956 was renamed 2956
    YEOMANS.

        Chairman Udall. Thank you, Dr. Yeomans. You all heard the
    bells ringing. One vote has been called on the Floor of the
    House, so we are going to continue the hearing. Congressman
    Lampson will come back and relieve me, so we can make the best
    use of your time and the Committee's time.
        So, thank you, Dr. Yeomans. We will move to Dr. Campbell.
    Looking forward to your testimony, sir.

     STATEMENT OF DR. DONALD B. CAMPBELL, PROFESSOR OF ASTRONOMY,
        CORNELL UNIVERSITY; FORMER DIRECTOR, ARECIBO OBSERVATORY

        Dr. Campbell. Mr. Chairman and Members of the Committee,
    thank you for this opportunity to address you on the role of
    radar, and specifically, the radar system on the giant Arecibo
    Telescope in Puerto Rico, in the tracking and characterization
    of NEOs, and the current state of funding of this National
    Science Foundation facility.
        Dr. Yeomans has just described the importance of precision
    radar measurements in predicting the future orbits of NEOs, and
    determining which NEOs are really hazardous to Earth. For these
    hazardous objects, additional precision radar measurements are
    extremely important to assess the impact probability and the
    need to take action to mitigate the threat.
        Near-Earth asteroids form a very diverse population,
    encompassing a large range of sizes, shapes, rotation states,
    densities, internal structure, and binary nature. It is
    important to understand the range of these characteristics in
    order to design suitable mitigation strategies. While a very
    small number of NEOs have been visited by spacecraft, radar
    provides by far the best means to survey these characteristics
    for a large number of objects. For an object that we know poses
    a direct threat to Earth, radar can provide vital input to
    mitigation planning.
        As you have heard, there are only two very high powered
    radars in the world capable of studying solar system bodies
    including NEOs. One is on the NSF's Arecibo Telescope, and the
    other is on NASA's Deep Space Network 70 meter antenna in
    California. The Arecibo radar is over 20 times more sensitive
    than the one on the Goldstone antenna, and has been the
    dominant contributor to near-Earth asteroid characterization
    and orbit prediction. However, the Goldstone antenna can look
    at more of the sky than Arecibo, making the two systems very
    complementary. They should both be preserved.
        In 2005 and 2006, the NSF Division of Astronomical Sciences
    undertook a Senior Review to examine the balance of its
    investments in various astronomical facilities the Division
    supports, including the Cornell University-based National
    Astronomy and Ionosphere Center, which operates the Arecibo
    Observatory for the NSF. The report was submitted to the NSF in
    November 2006. Despite considerable input to the Committee from
    both the National Astronomy and Ionosphere Center and the
    planetary community, the Arecibo Planetary NEO Radar Program is
    essentially ignored in the Committee's report.
        The report recommended that NAIC's operating funds provided
    by the NSF's Division of Astronomical Sciences be reduced over
    the following three years from approximately $10.5 million to
    $8 million, and then in Financial Year 2011, be halved again to
    $4 million. At the $8 million level, budgetary pressures are
    likely to make the termination of the radar and NEO program
    unavoidable, unless additional funding is found. In the
    slightly longer-term, if Cornell cannot find the additional
    funding needed to keep the Observatory open, then, in the
    report's words, ``The Senior Review recommends closure after
    2011 if the necessary support is not forthcoming.''
        If the Arecibo radar system is decommissioned, it would
    leave the lower sensitivity NASA Goldstone system as the only
    radar in the world capable of precise orbit determination for
    NEOs and measurements characterizing their physical properties.
    It will probably be unable to fill the void, especially with
    the large number of NEOs likely to be detected over the next
    decade or more.
        Replacing the Arecibo Telescope and radar system with a
    mission-specific facility of equal sensitivity would cost
    several hundred million dollars. Given its contributions to the
    NEO program and other research areas, and the relatively small
    budget needed to keep it operating, closing Arecibo does not
    make sense.
        In answer to the question as to how much it would cost to
    support Arecibo for NEO activities, independent of any other
    use of the telescope, the budget would probably need to be very
    roughly the same as the Observatory's current budget, about $10
    million per year. Most of the operating costs of large
    telescopes are fixed costs, relating to such things as
    maintenance, independent of the science mission.
        In summary, Earth-based radar provides critical information
    related to NEO orbit prediction and characterization. Arecibo
    is the primary radar involved in this activity, and will remain
    so for at least the next 10 years provided that both the
    Observatory and its radar system are adequately funded.
        If the Arecibo Observatory is closed, a unique research
    capability will be lost that makes valuable contributions not
    only to the study of Near-Earth Objects, but in other areas of
    astronomy and atmospheric science. One of Puerto Rico's main
    research facilities, and a spectacular structure as you saw
    earlier, the Arecibo Telescope is important to local education
    and tourism. Its closing would be a major loss to both science
    and the island.
        Thank you for your attention.
        [The prepared statement of Dr. Campbell follows:]

                    Prepared Statement of Donald B. Campbell

        Mr Chairman and Members of the Committee, thank you for this
    opportunity to address you on the important issue of near-Earth objects
    and their potential threat to Earth.
        I have been asked to address issues related to the use of radar
    systems to track and characterize near-Earth objects (NEOs) and,
    specifically, to address the role of the radar system on the giant
    Arecibo telescope in Puerto Rico in this activity and the current state
    of funding for this National Science Foundation facility. I will
    address these questions in turn.

      What role do Earth based radars play in the tracking and
    characterization of Near Earth Objects (NEOs)? What role, if any, do
    they play in providing information about specific hazardous objects?

        Radar plays an important role in predicting the future orbits of
    NEOs and measuring many of their physical characteristics such as size,
    shape, rotation state and, in the case of binary objects, their mass
    and density. Radar can measure distances to NEOs to an accuracy of
    about 10m (30 ft) and their line-of-sight velocity to an accuracy of
    about one mm per second (12 ft per hour), orders of magnitude better
    than the equivalent optical measurements. For potentially hazardous
    objects (PHOs), optical observations based on measuring their changing
    position on the sky over days or weeks in many instances cannot rule
    out a possible future impact with the Earth. To do so can require
    optical positional measurements spanning years or decades. For future
    searches, radar astrometry, the measurement of distance and line-of-
    sight velocity, can be used to help cull the number of PHOs--not all
    the newly detected NEOs will be observable with radar--so that we can
    concentrate on the few that really are potentially hazardous. For these
    objects, additional precision radar measurements are extremely
    important to assess the impact probability and the need to take action
    to mitigate the threat.
        The more we know about NEOs in general and about specific ones that
    pose a threat to Earth, the easier it will be to design effective
    mitigation strategies. ``Know your enemy'' would seem to be good advice
    in this instance. NEOs form a very diverse population encompassing a
    large range of sizes, shapes, rotation states, densities, internal
    structure and binary nature. While a very small number of NEOs have
    been visited by spacecraft, radar provides by far the best means to
    survey these characteristics for a large number of objects. Knowing the
    range of characteristics facilitates the design of effective mitigation
    techniques that can be applied to an object with any of these
    characteristics. For an object that we know poses a direct threat to
    Earth, radar can provide vital input to mitigation planning including
    planning for any precursor space mission.
        Over the past few years, the accuracy of the Earth impact
    prediction based on precision radar astrometry for a few PHOs has been
    limited not by the accuracy of the radar measurements but by the
    inability to accurately model all of the very small forces on these
    objects in addition to that due to the Sun's gravity. One of these
    forces, the Yarkovsky effect, is related to sunlight absorbed by the
    body and its re-emission as heat. Precision radar astrometry over
    several years of a small asteroid, Golevka, demonstrated in 2003 that
    this effect can modify the orbits of small asteroids over very long
    periods of time. This has revolutionized our understanding of how small
    asteroids in the main asteroid belt between Mars and Jupiter are
    transported into the inner solar system to become NEOs and, some, PHOs.
    This new understanding resulting from a basic science driven project
    will also help in refining PHO Earth impact probabilities for the few
    objects that may be of real concern.

      What role has the Arecibo Observatory played in surveying
    NEOs and what are the impacts to the NEO program should Arecibo be
    decommissioned?

        The radar system on the NSF's Arecibo Telescope in Puerto Rico is
    one of only two very high powered radars in the world that are used for
    studying solar system bodies including NEOs. The other one is on NASA's
    Deep Space Network 70m antenna at Goldstone in California's Mojave
    desert. With its 300m (1,000 ft) diameter telescope and radiated power
    of one megawatt, the Arecibo radar is over 20 times more sensitive than
    the one on the Goldstone antenna. However, because of its limited
    steerability, Arecibo can only observe about half the sky observable
    with the Goldstone antenna making the two systems very complementary.
        Because of its greater sensitivity and availability, the Arecibo
    radar system has carried out 65 percent of all radar observations
    characterizing NEOs, 47 percent of the known binary NEOs were
    discovered with Arecibo (most of the rest were discovered with optical
    telescopes), and data from Arecibo was used for 85 percent of the NEOs
    for which precision radar distance and velocity astrometric
    measurements have been made for orbit determination.
        If the Arecibo radar system is decommissioned it would leave the
    lower sensitivity radar system on the NASA 70m Goldstone antenna as the
    only radar system in the world capable of precise astrometry of NEOs
    and measurements characterizing their physical properties. A tremendous
    amount of basic science related to NEOs and other solar system bodies
    would be lost and the highest sensitivity radar would no longer be
    available to provide precision astrometry and characterization data
    just as the NEO search programs are ramping to a new level. Given the
    pressures on the 70m Goldstone antenna in carrying out its prime
    mission, its lower sensitivity and the large number of NEOs likely to
    be detected over the next decade or more, it seems unlikely that this
    system could come close to filling the void. Replacing the Arecibo
    telescope and radar system with a mission specific facility of equal
    sensitivity would cost several hundred million dollars. Given its
    contributions to the NEO program and other research areas in radio
    astronomy and ionospheric physics and the relatively small budget
    needed to keep it operating, closing Arecibo does not make sense. In
    the words of Bill H.R. 3737, recently submitted by Congressman Fortuno
    on behalf of himself, Congressman Rohrabacher and other Members of the
    House of Representatives, ``The Arecibo Observatory is an invaluable
    and unique asset in warning and mitigating potential hazards posed by
    near-Earth objects.''

      Did the recent National Science Foundation (NSF) Senior
    Review of Arecibo evaluate the facility's role in surveying NEOs and
    the impact of Arecibo's potential decommissioning on the NEO survey
    program? If not, why not?

        The National Astronomy and Ionosphere Center (NAIC), the formal
    name for the Arecibo Observatory located in Puerto Rico, is one of the
    four National Astronomy Centers plus the U.S. component of the
    international Gemini observatory, funded through the Division of
    Astronomical Sciences at the NSF and is operated by Cornell University
    under a Cooperative Agreement with the NSF. NAIC is unique among the
    Centers in that it supports research in three diverse areas, radio
    astronomy, planetary radar astronomy including the study of NEOs, and
    ionospheric physics. The first two are supported through funding from
    the Division of Astronomical Sciences at the NSF while the ionospheric
    program, about 15 percent of the budget, is funded through the Division
    of Atmospheric Sciences at the NSF. NAIC has about 120 people working
    at the Arecibo Observatory in Puerto Rico. In addition to providing
    research facilities for its scientific user community, it operates a
    visitor center that attracts about 120,000 visitors a year most from
    Puerto Rico including about 25,000 school children.
        In 2005-2006 the Division of Astronomical Sciences of the National
    Science Foundation (NSF) undertook a ``Senior Review'' to examine the
    balance of its investments in the various astronomical facilities that
    the Division supports. The review was motivated by a combination of the
    budget outlook at that time for the Foundation and the ambitions of the
    astronomical community to invest in new facilities to address
    fundamental questions as recommended in the previous Astronomy Decadal
    Survey and other reports such as ``Connecting Quarks with the Cosmos.''
    The Senior Review committee submitted its report to the NSF in
    November, 2006.
        The aims of the Senior Review were widely supported by the
    astronomical community and it is not my intention to criticize its
    major findings. However, its charge was to look at the ``big picture''
    and in such a process small, high quality programs that are not central
    to the priorities of the committee or the NSF can end up becoming a
    casualty on the way to the main goal. Such seems to be the case for the
    planetary/NEO radar program at the Arecibo Observatory. During the
    review process, Cornell University and NAIC provided considerable input
    to the committee about the Observatory's research programs including
    the planetary/NEO radar program. Many planetary astronomers, especially
    those interested in NEOs, wrote to the Committee strongly supporting
    the Arecibo radar program. However, the Arecibo planetary/NEO radar
    program was essentially ignored in the committee's report with the only
    explanation I have heard being that the program was too small in
    funding terms to be individually considered. There were no planetary
    astronomers on the committee.
        I should emphasize that the Senior Review report did not recommend
    that the Arecibo planetary/NEO radar program be canceled but that is
    likely to be the outcome of its budgetary recommendations vis-a-vis
    NAIC. It recommended that NAIC's operating funds provided by the NSF
    Division of Astronomical Sciences, about 85 percent of its yearly
    budget with the rest coming from the NSF Division of Atmospheric
    Sciences, be reduced over the following three years from approximately
    $10.5M to $8M and then, in FY 2011, be halved again to $4M. By early
    2009 Cornell is required to have definite commitments from other
    entities for the additional operating funds needed to keep the
    observatory open. If it cannot get these commitments then, in the
    Senior Review report's words ``The Senior Review recommends closure
    after 2011 if the necessary support is not forthcoming.''
        The planetary/NEO radar program is scheduled to continue in
    operation at a reduced level of activity through FY 2008 compared with
    its normal use of about 400 hours of telescope time per year. If the
    NSF implements the Senior Review's recommendations to reduce NAIC's
    budget for astronomical research to the $8M level, budgetary pressures
    and deferred maintenance are then likely to make termination of the
    radar/NEO program unavoidable unless additional funding is found. Since
    the planetary/NEO radar system has significant operational and
    maintenance costs associated with the transmitting system, terminating
    it is the only identifiable way to save about $1M in operating costs
    short of canceling the observatory's entire radio astronomy program.
    The NSF has said that they will not augment NAIC's budget to provide
    support for the planetary radar/NEO program and has indicated that this
    area of research should be supported by NASA. Until a few years ago,
    NASA did provide partial support for the Arecibo radar program. In the
    slightly longer-term, if additional operating funds are not found well
    before the projected FY 2011 NSF/AST reduction to $4M then the Arecibo
    Observatory will possibly be closed definitely terminating its
    contributions to the tracking and characterization of NEOs.

      What level of funding and technical support would be required
    to carry out the NEO-related activities of Arecibo, independent of any
    other astronomy-related activities? Will any upgrades to the facility
    or its instruments be required?

        The current yearly cost for operating Arecibo's planetary radar
    system for about 400 hours a year is close to $1M. About 60 percent of
    this time is devoted to NEO research. This covers the cost of the
    operation and maintenance of the high powered transmitting capability
    plus several engineers and a small scientific staff. It does not cover
    major maintenance items for the transmitting system. It also does not
    cover the cost for the operation and maintenance of the telescope and
    the general support for grounds, buildings, etc., needed to keep the
    observatory operating as a facility. Prorating these costs based on the
    observing hours used would raise the current costs of the planetary
    radar program to close to $2M/yr.
        No study has yet been done of the precise role of the Arecibo radar
    and how many hours of NEO observations will be needed when the new,
    high sensitivity searches commence starting with Pan-STARRS. This needs
    to be done. The demand for the use of the Arecibo radar will
    undoubtedly increase significantly but whether by a factor of two or
    five is uncertain. While maintaining the observatory's multi-
    disciplinary program, some increase in the use of the radar system for
    NEO observations can certainly be accommodated. A program using about
    500 hours a year for NEO observations and, perhaps, 100 hours for radar
    studies of other solar system bodies would cost $2M to $3M including
    its share of general observatory support costs. The costs would prorate
    roughly with observing time.
        In answer to the question as to how much it would cost to support
    Arecibo for NEO activities independent of any other use of the
    telescope, the budget would need to be very roughly the same as the
    observatory's current budget, about $10M per year. Most of the
    operating costs of large telescopes are fixed costs related to
    maintenance, etc., independent of the science mission. However, I want
    to emphasize that any NEO radar program is unlikely to utilize all, or
    even a majority, of the observing time available on the telescope.
        The Arecibo telescope and radar system underwent a major NSF and
    NASA funded upgrading about ten years ago. At this time some major
    components of the transmitting system need refurbishment or replacement
    and some of the data handling equipment used for the NEO program needs
    updating. Total costs of this are estimated to be about $2M.

      What are your perspectives on NASA's Near-Earth Object Survey
    and Deflection Analysis of Alternatives Report to Congress?

        NASA's report was a comprehensive discussion of the issues related
    to the detection of 90 percent of all NEOs larger than 140m by 2020,
    the requirement to determine their orbits, understand the broad
    characteristics of different classes of asteroids in order to be able
    to design mitigation strategies, and, of course, the range of possible
    mitigation strategies. Staying within my area of expertise, the
    report's discussion on the usefulness of determining orbits with radar
    versus with optical means and the best means to characterize these
    objects to, in the report's words, ``inform mitigation'' should be
    revisited. For orbit determination the issue is whether a relatively
    quick refinement of at least some percentage of the orbits of newly
    discovered PHOs is preferable to waiting the 10 to 20 years that
    optical means require for orbit determinations that will as stated in
    the report ``nearly match the accuracy of radar-improved orbits.''
        The role of the radar systems in surveying the broad range of NEO
    types could also have been given more emphasis in the report. Radar is
    currently the only Earth or Earth-orbit based technique that has the
    resolution needed to provide information about a wide range of physical
    properties important to mitigation planning. The images below show the
    detailed shape model of the main component of the binary NEO 1999 KW4
    and a simulation of the binary system, results obtained by Steven Ostro
    of JPL and colleagues from observations using the Arecibo and Goldstone
    radars. The work was described in the cover article of Science magazine
    last November. We now know KW4's size, about 1.5 km (one mile) for the
    main body, shape, rotation rate, mass, density and that it is a binary
    object. The low density of the main body, about twice that of water,
    tells us that it is rubble pile rather than a single large ``rock.''
    This is all information that is critical to ``informing mitigation.''

        Chairman Udall. Thank you, Dr. Campbell.
        Next on the panel is Dr. Tyson, and I would, as a preface
    to his remarks, mention that as a Member of the Armed Services
    Committee, I am used to many, many acronyms, and I used one
    earlier in my comments to begin the hearing, about the LSST,
    which is the Large Synoptic Survey Telescope Project, and Dr.
    Tyson is a key part of that effort.
        So, Dr. Tyson, welcome, and the floor is yours.

       STATEMENT OF DR. J. ANTHONY TYSON, PROFESSOR OF PHYSICS,
       UNIVERSITY OF CALIFORNIA, DAVIS; DIRECTOR, LARGE SYNOPTIC
                        SURVEY TELESCOPE PROJECT

        Dr. Tyson. Thank you, Mr. Chairman and Members of the
    Committee. It is an honor to be asked to testify before you
    today on this important subject.
        The House Committee on Science has been a leader, on a
    bipartisan basis, over two decades, in focusing attention on
    the need to detect, characterize, and catalog near-Earth
    asteroids. The passage of the George E. Brown Near-Earth Object
    Survey Act was a landmark piece of legislation that sets a goal
    of cataloging 90 percent of NEOs of 140 meters in diameter and
    larger within 15 years.
        The Committee is properly looking at the existing and
    future capabilities of carrying out this goal and expanding the
    existing Spaceguard program. LSST adopted the goal of surveying
    NEOs at the outset as one of its major science capabilities. I
    have attached to the statement a nine page summary of the
    capabilities of LSST for detecting NEOs and obtaining their
    orbits.
        Until recently, the discussion of risk associated with an
    impact of NEOs has been statistical. In other words, what is
    the probability? This is similar to considerations of risk in
    many other areas, such as weather and traffic accidents. What
    if it were feasible to deploy a system that would alert me of
    an impending traffic accident well in advance? That would
    change the very nature of that risk from a probabilistic worry
    to a deterministic, actionable situation. The ability to detect
    virtually every potentially hazardous near-Earth object and
    determine its orbit with precision transforms that statistical
    threat into a deterministic prediction. We face many threats,
    and virtually all of them are either so complex or
    unpredictable that they are treated probabilistically, even
    though the social and financial consequences are legion. With a
    comparatively small investment, the NEO risk can be transformed
    from a probabilistic one to a deterministic one, enabling
    mitigation.
        Ground-based optical surveys are the most cost-effective
    tool for comprehensive NEO detection, determination of their
    orbits, and subsequent tracking. Radar, as we have heard, also
    plays an important role once the threatening NEO has been
    found, in refining its orbit when the NEO is near. The first
    job is to find the NEOs which are potentially hazardous, so-
    called potentially hazardous objects, or potentially hazardous
    asteroids, actually, from among the swarm of 10 million other
    asteroids.
        A survey capable of extending these tasks to NEOs with
    diameters as small as 140 meters, as mandated by Congress,
    requires a large telescope, a large camera, and a sophisticated
    data acquisition, processing, and dissemination system. This
    Congressional mandate drives the requirement for an eight meter
    class telescope with a 3,000 megapixel camera and a
    sophisticated and robust data processing system. These
    requirements are met by the LSST.
        The LSST is currently, by far, the most ambitious proposed
    survey of the sky. With initial funding from the National
    Science Foundation, Department of Energy laboratories, and
    private sponsors, the design and development efforts are well
    underway at many institutions.
        Fortunately, the same hardware and software requirements
    are driven by science unrelated to NEOs. LSST reaches the
    threshold where different science drivers, and therefore,
    different agencies, NSF, DOE, and NASA, can work together to
    efficiently achieve seemingly disjoint but deeply connected
    goals. This broad range of science has earned LSST the
    endorsement of a number of committees commissioned by the
    National Academy of Sciences. Because of this synergy, the
    Congressional mandate can be reached at only a fraction of the
    cost of a mission dedicated exclusively to NEO search.
        We have carried out over 100 computer simulations of the
    LSST operations for a variety of NEO optimized scenarios. The
    planned LSST baseline survey cadence on the sky, that is to
    say, the way you tile the sky with time, during the night, is
    capable of providing orbits for 82 percent of potentially
    hazardous asteroids larger than 140 meters after 10 years of
    operation, and is 90 percent complete for objects larger than
    230 meters. This baseline cadence assumes that five percent of
    the total observing time is spent on NEO specialized observing.
    This is what is currently planned.
        By increasing this fraction of NEO specialized surveying to
    15 percent, that is to say, from five to 15 percent, and by
    running the survey longer, the Congressional mandate of 90
    percent completeness for potentially hazardous asteroids of 140
    meters and greater size, can be fulfilled after 12 years of
    operation, with 60 percent completeness level reached after
    only three years. These specialized observations would be of
    limited use to other science programs, and they require 15
    percent of the observing time.
        The current cost estimate for LSST in 2006 dollars is $389
    million for construction, and $37 million per year for
    operations. For a 12-year long survey, 15 percent of this total
    cost is $125 million. Thus, we could deliver the performance of
    a full NEO dedicated LSST to NASA and to the world at a small
    fraction of the total cost to build and operate such a system.
    This cost is equivalent to 30 percent of operations, which
    would commence in 2014.
        Note that by operating LSST in this special NEO optimized
    mode, we would have the performance equivalent of an LSST fully
    dedicated to NEO serving. By supporting only 15 percent of the
    total cost, NASA would be essentially getting an NEO dedicated
    LSST. This is a key new insight, relative to the costing model
    in the 2007 NASA NEO report to Congress.
        Thank you.
        [The prepared statement of Dr. Tyson follows:]

                     Prepared Statement of J. Anthony Tyson

        Mr. Chairman and Members of the Committee. It is an honor to be
    asked to testify before you today on this important subject. By way of
    identification, I am an astrophysicist and Professor of Physics at the
    University of California, Davis, and Director of the Large Synoptic
    Survey Telescope (LSST) project; before coming to UC-Davis four years
    ago I did research and development at Bell Labs for 34 years.
        The House Committee on Science has been a leader on a bipartisan
    basis for over two decades in focusing attention on the need to detect,
    characterize, and catalog near-Earth asteroids. The passage of the
    ``George E. Brown Jr. Near-Earth Object Survey Act'' was a landmark
    piece of legislation that sets a goal of cataloging 90 percent of NEOs
    of 140 meters in diameter and larger within 15 years. The Committee is
    properly looking at the existing and future capabilities for carrying
    out this goal and expanding the existing Spaceguard program. LSST
    adopted the goal of surveying NEOs at the outset as one of its major
    science capabilities.
        Until recently, the discussion of risk associated with an impact of
    a NEO has been statistical; what is the probability? This is similar to
    considerations of risk in many other areas such as weather and traffic
    accidents. What if it were feasible to deploy a system that would alert
    me of an impending traffic accident well in advance? That would change
    the very nature of that risk from a probabilistic worry to a
    deterministic actionable situation. The ability to detect virtually
    every potentially hazardous Near-Earth object and determine its orbit
    with precision transforms that statistical threat into a deterministic
    prediction. We face many threats, and virtually all of them are either
    so complex or unpredictable that they are treated probabilistically
    even though the social and financial consequences are legion. With a
    comparatively small investment the NEO risk can be transformed from a
    probabilistic one to a deterministic one, enabling mitigation.

    The First Job: Finding the NEOs

        Ground-based optical surveys are the most efficient tool for
    comprehensive NEO detection, determination of their orbits and
    subsequent tracking. (Radar also plays an important role once a
    threatening NEO has been found, in refining its orbit when the NEO is
    near.) The first job is to find the NEOs which are potentially
    hazardous (so-called Potentially Hazardous Asteroids) from among the
    swarm of ten million other asteroids. A survey capable of extending
    these tasks to NEOs with diameters as small as 140m, as mandated by
    Congress, requires a large telescope, a large camera, and a
    sophisticated data acquisition, processing and dissemination system.
    The Congressional mandate drives the requirement for an eight-meter
    class telescope with a 3000 Megapixel camera and a sophisticated and
    robust data processing system. These requirements are met by the LSST.
        Why is a large telescope required? A typical 140-meter NEO appears
    very faint (visual magnitude of 25). Multiple NEO detections in a
    single night are required to estimate its motion, so that its future or
    past detections can be linked together. This linkage has to be done
    exceedingly robustly because the near-Earth objects will be outnumbered
    nearly a thousand to one by main-belt asteroids (between Mars and
    Jupiter) which present no threat to Earth. By reliably linking
    detections on multiple nights, the NEO's orbit can be reconstructed and
    used to compute its impact probability with Earth. Despite their name,
    NEOs are typically found far from Earth. In principle, very faint
    objects can be detected using long exposures, but for objects moving as
    fast as typical NEOs, the so-called trailing losses limit the exposure
    time to about 30 seconds. In order to detect 140-meter NEOs in 30
    seconds, an eight-meter class telescope is required.
        Why is a large camera required? The need for a very large field of
    view comes from the requirement that the whole observable sky should be
    observed at least every four to five nights. For comparison, we need a
    field of view thousands of times larger than the Hubble Space
    Telescope's Advanced Camera for Surveys. With its 10 square degree
    field of view, LSST will be able to reach the mandated high NEO
    completeness.

    Finding Near-Earth Objects with Ground-based Surveys

        Ground-based optical surveys are a very cost effective tool for
    comprehensive NEO detection, determination of orbits, and subsequent
    tracking. A survey capable of extending these tasks to NEOs with
    diameters as small as 140m, as mandated by Congress, drives the
    requirement for a large telescope, a large camera, and a sophisticated
    data acquisition, processing and dissemination system.
        To find a significant fraction of the faint NEOs one must
    essentially make a movie of the deep sky. Each faint asteroid must be
    captured in many separate exposures in order for computers to
    distinguish it from the numerous other asteroids and then piece
    together its orbit. A large area of the sky (ideally all the sky
    visible from some location on Earth, at least 20,000 square degrees)
    must be surveyed rapidly and deeply in order to survey a large volume
    for these faint asteroids. The ability of a telescope and camera to
    take rapid deep repeated images of the entire sky is proportional its
    ``throughput.'' Throughput (sometimes called etendue) is simply the
    product of the telescope light collection area (units: square meters)
    times the camera field of view in a single snapshot (units: square
    degrees). Thus throughput of a survey facility is measured in units of
    square meters square degrees. The throughput of LSST is 320 square
    meters square degrees. High throughput is a necessary condition for
    such a facility to carry out its mission, but not a sufficient
    condition: one must also arrange to have high observing efficiency
    (access to the sky) and highly efficient optics and imaging detectors
    in the camera, as well as superb image quality.
        For an efficient NEO survey, the whole observable sky should be
    observed at least every four to five nights, with multiple observations
    per night. In order to do so with exposure time of about 30 seconds per
    observation, a 10 square degree large field of view is required. Such a
    large field of view, with pixel size sufficiently small to fully sample
    the image at a good observing site, implies a multi-billion pixel
    camera. Indeed, at the time of its completion, the 3.2 billion pixel
    LSST camera will be the largest astronomical camera in the world.
        With a 3.2 billion pixel camera obtaining images every 15 seconds
    (individual 30 second exposures are split into two 15 second exposures
    for technical reasons), the data rate will be about 20 thousand
    gigabytes per night. Not only is this a huge data rate, but the data
    have to be processed and disseminated in real time, and with exquisite
    accuracy. It is estimated that the LSST data system will incorporate
    several million lines of state-of-the-art custom computer code.

    State of the LSST project

        The Large Synoptic Survey Telescope (LSST) is currently by far the
    most ambitious proposed survey of the sky. With initial funding from
    the U.S. National Science Foundation (NSF), Department of Energy (DOE)
    laboratories and private sponsors, the design and development efforts
    are well underway at many institutions, including top universities and
    leading national laboratories. The main science themes that drive the
    LSST system design are Dark Energy and Dark Matter, the Solar System
    Inventory, Transient Optical Sky and the Milky Way Mapping. It is this
    diverse array of science goals that has generated the widespread
    excitement of scientists ranging from high-energy physicists to
    astronomers and planetary scientists, and earned LSST the endorsement
    of a number of committees commissioned by the National Academy of
    Sciences.
        Fortunately, the same hardware and software requirements are driven
    by science unrelated to NEOs: LSST reaches the threshold where
    different science drivers and different agencies (NSF, DOE and NASA)
    can work together to efficiently achieve seemingly disjoint, but deeply
    connected, goals. Because of this synergy the Congressional mandate can
    be reached at only a fraction of the cost of a mission dedicated
    exclusively to NEO search.
        The scientific priority for constructing a large aperture ground
    based survey telescope was recommended in the astronomy and
    astrophysics Decadal Survey 2000 report entitled Astronomy and
    Astrophysics in the New Millennium. Since then, LSST has reached a high
    state of design maturity. LSST has recently passed the NSF Conceptual
    Design Review for construction, which puts it on track for transition
    to Readiness in spring 2008. LSST is a public-private project. To date
    $44M in private funding has been raised. Twenty two institutions have
    joined the effort and have contributed significant in-kind technical
    labor. LSST R&D continues for another three years under NSF support
    along with in-kind contributions. The project is on track for first
    light in 2014. It is proposed that the DOE (because of the importance
    of LSST for addressing the mystery of dark energy) support the $80M
    cost of constructing the camera. Foreign support now appears likely,
    and this in-kind would offset the camera cost.

    Method of Study: the LSST Operations Simulator

        The LSST Operations Simulator was developed to be able to do just
    the sort of assessment described in this document. It contains detailed
    models of site conditions, hardware and software performance, and an
    algorithm for scheduling observations which will, eventually, drive the
    robotic LSST observatory. The resulting sky coverage for the LSST
    baseline cadence is shown in Figure 1.
        For the currently planned LSST baseline cadence, objects counted as
    cataloged are observed on 20 different nights on average. A more
    stringent requirement could decrease the completeness by up to three
    percent. The completeness is also a function of the assumed size
    distribution: the flatter the distribution, the higher the
    completeness. If the latest results for the NEO size distribution by A.
    Harris are taken into account, the completeness increases by one to two
    percent. Due to these issues, the completeness estimates have a
    systematic uncertainty of two percent. Our analysis assumes that no
    NEOs are known prior to LSST. Current surveys make a negligible
    contribution to the 90 percent completeness for NEOs of 140m and up.

    The NEO survey completeness achievable with LSST

        The LSST system is the only proposed astronomical facility that can
    detect 140-meter objects in the main asteroid belt in less than a
    minute. The LSST system will be sited at Cerro Pachon in northern
    Chile, with first light scheduled for 2014. In a continuous observing
    campaign, LSST will cover the entire available sky every four nights,
    with at least two observations of an NEO per night. Over the baseline
    survey lifetime of 10 years, each sky location would be observed over
    800 times. Two NEO detections in a single night are required to
    estimate its motion, so that its future or past detections can be
    linked together. This linkage has to be done exceedingly robustly
    because the near-Earth objects will be outnumbered a hundred to one by
    main-belt asteroids which present no threat to Earth. By reliably
    linking detections on multiple nights, the NEO's orbit can be
    reconstructed and used to compute its impact probability with Earth.
        The currently planned LSST baseline observing cadence on the sky,
    described in the Major Research Equipment and Facilities Construction
    proposal submitted to NSF, is simultaneously optimized for all four
    main science drivers: Characterizing Dark Energy and Dark Matter, the
    Solar System Inventory, Transient Optical Sky, and the Milky Way
    Mapping (see Figure 1). Computer simulations of LSST observing show
    that the data stream resulting from this baseline cadence on the sky is
    capable of providing orbits for 82 percent of Potentially Hazardous
    Asteroids (PHA) larger than 140 meters after 10 years of operations.
    The completeness curve as a function of time since the start of the
    survey is shown in Figure 2 (second curve from top). This baseline
    cadence spends five percent of the total observing time on NEO-
    optimized observations in the north region of the ecliptic (plane of
    the solar system).
        Various adjustments to this baseline cadence can boost the
    completeness for 140m and larger PHAs to 90 percent. Based on about 100
    different simulations, we find that such adjustments to the baseline
    cadence or filter choices can have unacceptably large impact on other
    science programs, if the 90 percent completeness is to be reached
    within 10 years from the beginning of the survey. However, with a minor
    adjustment of the baseline cadence and additional specialized observing
    for NEOs, this completeness level can be reached with a 12-year long
    survey, and with a negligible effect on the rest of science goals.
        These specialized observations would be of limited use to other
    science programs, and they require 15 percent of the observing time.
    The dependence of completeness for 140m and larger objects on time is
    shown in Figure 2. For LSST, Figure 2 shows the baseline survey and the
    special NEO-optimized survey. In addition, we also show completeness
    curves for the same observing cadence and under the same assumptions
    regarding seeing and efficiency for smaller versions of LSST of less
    throughput. The lowest curve (black line) in Figure 2 shows the
    completeness for current NEO assets (ca. 2014-) for comparison.

    Conclusions

        The ability of LSST to reach the mandated 90 percent completeness
    for 140m and larger PHAs in 10 years by the so-called ``dedicated''
    option described in the 2007 NASA NEO report is supported by our
    detailed and realistic simulations. An important additional insight
    from these simulations is that we can deliver the performance of a
    ``dedicated'' system by spending 85 percent of the total observing time
    on a general survey useful for all LSST science programs, and by
    specializing only about 15 percent of the total observing time for NEO
    surveying. If such an NEO-optimized program is executed for 12 years,
    the 90 percent completeness for 140m and larger PHAs can be reached
    without a significant negative impact on other science programs.
        The current cost estimate for LSST in 2006 dollars is $389M for
    construction and $37M per year for operations. For a 12-year long
    survey, 15 percent of the total cost is $125M. Thus, we could deliver
    the performance of a full NEO-dedicated LSST to NASA at a small
    fraction of the total cost to build and operate such a system. This
    cost is equivalent to 30 percent of operations, which would commence in
    2014. To assure LSST keeps on schedule, about $5M should be spent on
    optimized NEO orbit software pipeline development in the last phase of
    R&D and the construction phase, 2009-2014.

    Executive Summary

        In December 2005 Congress directed NASA to implement a near-Earth
    object (NEO) survey that would catalog 90 percent of NEOs larger than
    140 meters in 15 years. In order to fulfill the Congressional mandate
    using a ground-based facility, an eight-meter class telescope equipped
    with a 3200 Megapixel camera, and a sophisticated and robust data
    processing system are required. These criteria are met by the Large
    Synoptic Survey Telescope (LSST). We have carried out over 100
    simulations of the LSST operations for a variety of NEO-optimized
    scenarios. The planned LSST baseline survey cadence on the sky,
    simultaneously optimized for all main science drivers, is capable of
    providing orbits for 82 percent of PHAs larger than 140 meters after 10
    years of operation, and is 90 percent complete for objects larger than
    230 meters. This baseline cadence assumes that five percent of the
    total observing time is spent on NEO-specialized observing. This is
    what is currently planned. By increasing this fraction to 15 percent
    and by running the survey longer, the Congressional mandate of 90
    percent completeness for NEOs of 140m and greater size can be fulfilled
    after 12 years of operation, with 60 percent completeness level reached
    after only three years.
        Note that by operating LSST in this special NEO-enhanced mode we
    would have the performance equivalent of an LSST fully dedicated to NEO
    surveying. By supporting only 15 percent of the total cost, NASA would
    be essentially getting a NEO-dedicated LSST. This is a key new insight
    relative to the costing model in the 2007 NASA NEO report to Congress.

                         Biography for J. Anthony Tyson

        J. Anthony ``Tony'' Tyson, distinguished Professor of Physics at
    University of California, Davis, is an experimentalist interested in
    gravitational physics. His current research is in cosmology: dark
    matter distribution, gravitational lens effects, cosmic shear, and the
    nature of dark energy. These investigations involve software for
    pattern recognition, detection of transients in images, large database
    handling and processing, and new instrumentation for optical astronomy.
    He directs a national effort to build a new kind of telescope/camera
    called the Large Synoptic Survey telescope (LSST). With its large
    aperture and wide field of view, LSST promises to shed light on the
    mysterious ``dark energy'' that is considered to be the most urgent
    problem in the physics of our universe.
        Tony Tyson received his B.S. in Physics from Stanford in l962 and a
    Ph.D. from University of Wisconsin at Madison in 1967, and a
    postdoctoral fellowship at the University of Chicago. He is a Fellow of
    the American Physical Society and the American Academy of Arts and
    Sciences, and a member of the National Academy of Sciences and the
    American Philosophical Society.

        Mr. Lampson. [Presiding] Thank you, Dr. Tyson. Mr.
    Schweickart.

    STATEMENT OF MR. RUSSELL ``RUSTY'' L. SCHWEICKART, CHAIRMAN AND
                        FOUNDER, B612 FOUNDATION

        Mr. Schweickart. Mr. Chairman, Mr. Ranking Member Feeney,
    and Members of the Committee, Mr. Lampson, I thank you for
    giving me the opportunity here to testify on the Near-Earth
    Object situation, on NASA's report to Congress on the matter,
    and on where we need to go from here.
        With very limited time, I will jump right into the four
    questions I was asked to address, and our six specific
    recommendations pertaining to it. We were asked first to
    provide our perspectives on NASA's report to Congress, and
    whether we agree or disagree with the report's findings and
    recommendations.
        The first two elements of the Congress' directive related
    to analyzing ways of meeting the new goal, as we have heard,
    and a specific directive to recommend a program and a budget to
    support it. NASA completely ignored Congress' direction to
    recommend a search program and supporting budget. I want to
    emphasize here, picking up on Chairman Udall's earlier comment
    that not only did the Congress direct NASA to make a
    recommendation and a budget to support it, but the President
    signed that into law, so it is in law by both the President and
    the Congress.
        So, our first recommendation is that Congress should again
    direct NASA, in the clearest language possible, to comply with
    the law, and recommend a search program and supporting budget.
        With regard to Congress' directive, the third task of NASA,
    that they analyze possible alternatives that could be employed
    to divert an object on a likely collision course with Earth, we
    highlight only two of the many technical flaws in NASA's report
    to Congress. The first of those, NASA misinterpreted the
    Congressional intent, and elected to consider forward
    deflection, to look at what would be required, only a set of
    very large, very improbable Near-Earth Objects, rather than the
    far more frequent but still devastating impacts which we are
    much more likely to encounter.
        Assuming, therefore, this extraordinary demand, NASA
    naturally came up with an extraordinary response, namely, the
    use of nuclear explosives. In fact, 99 percent of the NEOs most
    likely to trigger a call for deflection can be diverted by non-
    nuclear kinetic impacts, that is, simply running into the Near-
    Earth Object with a spacecraft, similar to what was done by
    NASA on July 4, 2005, in the Deep Impact crash into Comet
    Tempel 1.
        In a letter clarifying the Congressional intent,
    Congressman Dana Rohrabacher stated that: ``The first order of
    business is to ensure that we have a clear understanding of
    what the options are for the situations we are most likely to
    encounter.'' When shown this letter, NASA's comment to us, in a
    June 18, 2007 meeting was, to paraphrase it: ``If we had seen
    this letter at the time we began the study, we might have come
    out with a different report.'' Bottom line, nukes are not
    necessary, except in extremely rare and unusual circumstances.
        The second serious flaw in NASA's report is that NASA
    failed to understand and address the fact that whenever an
    asteroid passes near the Earth, for example, as the result of a
    deflection, it passes through a region in which are scattered
    hundreds of impact keyholes, small areas through which, if the
    asteroid passes, it will return in a few years to impact the
    Earth. Any deflection which causes an impacting asteroid to
    avoid hitting the Earth will end up, instead, passing through
    this minefield of impact keyholes. A successful deflection,
    therefore, depends upon the use of both a primary deflection,
    that is, to miss the Earth, using an appropriate impulsive
    technique, that is, a kinetic impact, or in exceptional cases,
    a nuclear explosion, and a potential secondary deflection, if
    it is headed for a keyhole, using a slow push capability, to
    ensure that the NEO both misses the Earth and misses the
    keyholes, therefore avoiding placing it on a return trajectory
    with an impact in a few years.
        Again, in our meeting on June 18, 2007 with NASA, they
    acknowledged that at the time the analysis was done, it did not
    understand the importance of this issue. Bottom line, both
    strength and precision are necessary for a successful
    deflection.
        Moving on, the second question I was asked to address was
    which relevant factors, data, or options are not addressed in
    the report, and how should NASA investigate those areas. Given
    the two serious flaws in NASA's report, which I just cited, as
    well as many others that are outlined in detail in my written
    testimony, we recommend, number two, that NASA should produce a
    supplement to its report to Congress, based on new knowledge
    which has come to light since it began its analysis.
        The third question Congress asked me to respond to was what
    does NASA need to do now to understand and mitigate the risks
    of potential NEO impact? Absent someone in NASA going beyond
    the search and discovery challenge, and thinking through the
    complex issues of NEO deflection, we stand justly accused of
    focusing on numeric goals for the sake of meeting an abstract
    quota, that is, 90 percent of so many objects, et cetera, et
    cetera. We therefore recommend that NASA, our third
    recommendation, that NASA should assign someone in its NEO
    program to the specific task of thinking through, analyzing,
    and understanding the NEO deflection challenge.
        And in addition, our fourth recommendation, based on this
    question, is that NASA should validate the basic NEO deflection
    capability, through the execution of a demonstration asteroid
    deflection mission. That is, we should not be put in the
    position of doing a deflection mission for the first time when
    lives actually count on it.
        Finally, we were asked what governance structure should be
    established to address potential NEO threats. This is, by far,
    the most important question that I was asked by the Congress.
    NASA, as the U.S., and arguably the world's premier space
    agency, should have the responsibility for both fully
    understanding the NEO deflection challenge and developing and
    testing deflection technology. It does not have that
    responsibility now.
        Therefore, our fifth recommendation is that the Congress
    expressly assign to NASA the technical development elements of
    protecting the Earth from NEO impacts as a public safety
    responsibility. That is, without NASA having the specific
    responsibility assigned to it to develop the technical means of
    protecting the Earth from NEO impacts, it will not be done.
    They must be assigned this responsibility. Otherwise, there
    will not be action in this regard.
        The larger question, however, is to which agency of
    government should the overall responsibility for protecting the
    Earth from NEO impacts be assigned, not just the technical
    development aspects, but the policy and political
    responsibility. This inherently international issue will
    involve complex and very sensitive coordination and
    negotiation, and the U.S. involvement will place in the hands
    of the agency responsible the lives and property of potentially
    the entire population.
        We, therefore, recommend as our final and sixth
    recommendation that the Congress study the issue of overall
    governmental responsibility for protection of the Earth from
    NEO impacts, perhaps with the assistance of specialized policy
    entities, and ultimately, to hold public hearings to engage a
    wide perspective on this issue.
        The logical candidates, obviously, for this overall
    responsibility are the Department of Homeland Security, the
    Department of Defense, and of course, NASA itself.
        This has been, of necessity, a very cursory review of a
    very important set of issues and questions. I thank you for the
    opportunity to discuss them with you, and I look forward to
    responding to any questions you may have.
        [The prepared statement of Mr. Schweickart follows:]
                  Prepared Statement of Russell L. Schweickart

    Mr. Chairman and Members of the Committee:

        Thank you for the opportunity to testify on this important subject;
    an issue of increasing interest regarding the protection of life and
    property around the planet.
        I represent B612 Foundation (B612), a private non-profit
    corporation founded in 2002 by a group of astronauts, astronomers,
    planetary scientists and engineers to advocate and develop the means of
    diverting a near-Earth object (NEO) threatening an impact with Earth.
    B612 has developed several alternative concepts for deflecting NEOs and
    we have actively urged NASA, the Congress, and others to pursue the NEO
    challenge beyond search and discovery and into mitigation and
    prevention.
        I will start by commending the Committee for its efforts since the
    early 1990s in seeing that this public safety issue is responsibly
    addressed. The impact of near-Earth objects with the Earth is properly
    described as a cosmic natural hazard of potentially unprecedented
    dimension, threatening both life and property. Unlike other natural
    hazards, however, we can in this instance, using current space
    technology, both predict and prevent the occurrence of such a disaster.
        No other natural hazard presents such a wide range of potential
    destruction, but in no other case are we fortunate enough to have at
    hand the advanced technology and creative imagination to mitigate such
    a catastrophic event. The range of explosive impacts we may be called
    on to prevent extend from the ``Tunguska Event'' of 1908, approximately
    a five megaton (MT) explosion over Siberia (equivalent to over 300
    Hiroshima bombs) up to impacts 100,000 times larger--large enough to
    destroy civilization and threaten the survival of humanity. We intend
    to prevent such infrequent but devastating events by slightly and
    precisely modifying the orbit of a threatening NEO, causing it to pass
    harmlessly by the Earth. Stated differently, we intend, using available
    space technology, to slightly alter the workings of the solar system in
    order to enhance human survival on planet Earth.
        To realize such a bold claim we must put in place three critical
    components of a response system. They are: advanced notice (i.e., an
    early warning system), a demonstrated deflection capability, and a
    standing decision process to enable timely action.
        The Congress, NASA, and other key global players are to be
    congratulated for their excellent work in implementing the first phase
    of the early warning system, the Spaceguard Survey, which has been in
    operation since 1998. The Congress is to be further commended for its
    vision in mandating that NASA take the next critical steps as expressed
    in the George E. Brown, Jr. Near-Earth Object Survey Act of 2005 (the
    Act). The Act extends the Spaceguard Survey goal, directing NASA to
    ``detect, track, catalogue, and characterize . . . near-Earth objects
    equal to or greater than 140 meters in diameter. . .'' and to ``achieve
    90 percent completion of [the survey] within 15 years after the date of
    enactment of this Act.''
        The Congress also directed that ``The Administrator shall transmit
    to Congress not later than one year after the date of enactment of this
    Act an initial report that provides the following:

            (A)  An analysis of possible alternatives that NASA may employ
            to carry out the Survey program, including ground-based and
            space-based alternatives with technical descriptions.

            (B)  A recommended option and proposed budget to carry out the
            Survey program pursuant to the recommended option.

            (C)  Analysis of possible alternatives that NASA could employ
            to divert an object on a likely collision course with Earth.''

        It is NASA's mixed response to these three directives which prompts
    my testimony here today.
        I have been specifically requested to address the following four
    questions;

            1.  What are your perspectives on NASA's Near-Earth Object
            Survey and Deflection Analysis of Alternatives Report to
            Congress? Do you agree or disagree with the report's findings
            and recommendations?

            2.  Which, if any, relevant factors, data, or options are not
            addressed in the report and how should NASA investigate those
            areas?

            3.  What does NASA need to do now to understand and mitigate
            the risks of potential NEO impacts?

            4.  What governance structures should be established to address
            potential NEO threats?

    1. Perspectives on the NASA Report

        My response to the first question is in three parts, corresponding
    to the three components of the Congressional direction to NASA.
    a) Analysis of Survey Program Alternatives:
        I believe that NASA did a very good job (with the exception of the
    NASA life cycle cost estimation for the several survey alternatives) in
    developing and comparing a set of alternative Survey designs to meet
    the 140-meter goal. While I am not personally qualified to comment on
    the NASA costing I note that knowledgeable Pan-STARRS and LSST
    personnel challenge the NASA figures used. These experts claim that the
    actual costs for both cooperative and dedicated use of such telescopic
    facilities are considerably lower than those projected by NASA.
        One factor not addressed in NASA's analysis of options to meet the
    revised Survey goal was the capability of various search system options
    for NEO tracking vice NEO discovery. While all of us in the NEO
    community strongly support moving aggressively to meet Congress's 140-
    meter discovery goal the fundamental intent of this enterprise is to
    protect the Earth from NEO impacts. This ultimate purpose is achieved
    by both the discovery of NEOs which might pose a threat AND also by
    tracking them accurately to determine whether or not a deflection
    campaign is necessary.
        It is an unfortunate reality that ground-based telescopic tracking
    produces, for many challenging NEOs, discontinuous information; data
    dropouts may last for several years at a time. Should such a critical
    data dropout occur just as a NEO is found to threaten an impact, the
    decision on mounting a deflection campaign may well have to be made on
    the basis of uncomfortably ``stale'' tracking data. The well-known NEO
    Apophis, which currently has a one in 45,000 probability of collision
    with the Earth in 2036, is in such a data dropout period at this time.
    We were last able to see Apophis in August 2006 and we will not see it
    again until 2011-2012. For Apophis this data interruption is
    uncomfortable, but not critical since we will see it again before we
    need to decide on a deflection campaign. This is, however, simply a
    matter of chance and in many instances in the future we will not be so
    fortunate.
        The orbital phasing responsible for this interrupted tracking can
    be eliminated by selecting any of several space-based search options in
    NASA's analysis to augment the ground-based systems. While NASA reports
    that overall costs for space and ground tracking are comparable (a
    controversial claim), the tracking quality provided by a telescope in a
    Venus-like orbit, in particular, is vastly superior. The dual-band IR
    telescope is especially preferable since it also improves greatly our
    estimates of NEO mass (and thus impact energy).
        In summary, NEO search and discovery is extremely important. NEO
    tracking, however, is equally important for deciding whether and when
    to mount a deflection campaign. The dual-band IR telescope in a Venus-
    like orbit offers both discovery and tracking advantages at a cost
    comparable to the best ground-based telescopic options.

    b) Recommended Program and Supporting Budget:
        With respect to the second Congressional charge to recommend a
    program to meet the 140-meter search goal and a budget to support it,
    NASA failed to respond. NASA opted instead to state the obvious, that
    ``. . . due to current budget constraints, NASA cannot initiate a new
    program at this time.'' Of course NASA's tight fiscal situation is
    precisely why the Congress requested not only a recommended program but
    also a proposed budget necessary to carry it out.
        One can sympathize with NASA's fear of the dreaded ``unfunded
    mandate'' from Congress while decrying the Agency's decision to defy
    the Congressional directive and to delay the initiation of this
    critical search program. Congress, however, must also recognize and
    confront the dilemma it imposes on NASA (and other agencies) when it
    directs action without the specific identification of funds to support
    the work. Yet given that Congress explicitly directed in its mandate
    that NASA provide it with a proposed budget to support the program NASA
    cannot be excused.
        I can only urge that the Congress should again direct NASA in the
    clearest language possible to comply with the law and recommend a
    search program and supporting budget. (Recommendation 1) It is time for
    the Nation to aggressively pursue this urgent NEO program.

    c) Analysis of Deflection Alternatives:
        B612 Foundation believes that NASA's analysis of deflection
    alternatives, as reported to the Congress, has serious technical flaws.
    NASA's findings and recommendations misunderstand, mischaracterize, and
    misrepresent many of the critical issues and options involved in the
    diversion of a threatening NEO. Furthermore the NASA Report fails to
    address a number of crucial issues which lie at the very heart of the
    deflection challenge.
        An analysis of the errors of both commission and omission are too
    numerous and detailed to include in this testimony. I have therefore
    attached to this written testimony, and urge the Members and their
    staff to read, several documents which address these errors in depth.
    These documents include:

            1.  An exchange of correspondence with Congressman Dana
            Rohrabacher regarding clarification of the intent of the
            Congress in the nature of the NEOs to be considered for
            diversion (attachments 1 & 2),

            2.  An ``Independent Analysis of Alternatives that could be
            employed to divert a NEO on a likely collision course with
            Earth.'' (attachment 3; also available at http://
            www.b612foundation.org/press/press.html, #15), and

            3.  Two detailed critiques of the NASA Report addressing on a
            point-by-point basis specific errors in the NASA analysis.
            (attachments 4 & 5; also available at http://
            www.b612foundation.org/press/press.html, #16).

        To appreciate the depth of the technical errors in the Report, I
    strongly urge that these appended documents be reviewed in detail. I
    will summarize here a few of the key points.

    Size matters

        In examining the technical alternatives for diverting threatening
    NEOs, NASA selected ``. . . a set of five [note: there were actually 7]
    scenarios representing the likely range of threats.'' In fact, the set
    of impact scenarios NASA chose as ``typical'' were extraordinarily
    challenging, resulting in a preference for a deflection concept
    delivering extraordinary capability, i.e., nuclear explosives.
        The least challenging of the NEOs NASA considered in its analysis
    is part of a group that comprises just two percent of the potential
    impact cases. The impact frequency of such an object is once every
    35,000 years. The remaining objects considered by NASA range upward to
    a one kilometer asteroid (one impact per million years) and a one-
    kilometer, long-period comet (even more rare).
        In fact, objects which hit much more frequently and yet deliver
    considerable impact energy make up 98 percent of the likely impact
    threat. The most likely of these objects to impact is comparable to the
    Tunguska event of 1908 in Siberian Russia. That event is estimated to
    have exploded with the force of about five megatons of TNT equivalent,
    or over 300 Hiroshima bombs. Had the Tunguska event been instead the
    ``London event,'' or ``Moscow event,'' it would have destroyed not just
    800 square miles of forest and a few reindeer but an entire city and
    its population.
        As Congressman Dana Rohrabacher stated in his clarification letter
    to B612 on this subject, ``While it is important to understand what
    technology exists or needs to be developed to divert the larger and
    more devastating NEOs the first order of business is to insure that we
    have a clear understanding of that the options are for the situations
    we are most likely to encounter.''
        A random impact occurring directly over a major city is, of course,
    highly unlikely. Yet when the possibility of such an event and the
    means of preventing it from occurring are known to exist by the general
    population it is reasonable to conclude that public pressure on the
    international community will successfully demand that we initiate a
    deflection.
        Given then a cohort of ``most likely NEOs to be deflected'' ranging
    from a Tunguska-like object at the smallest and most frequent end of
    the scale up to events 100 times less frequent, we find that over 99
    percent of them can be deflected using non-nuclear means.
        The need for the availability of nuclear explosions for deflection
    in extreme cases cannot currently be ruled out, but the likelihood of
    such a demand materializing over the next several decades is extremely
    small. Furthermore our search efforts will make the need for such a
    solution increasingly unlikely over time.

    Precision matters

        NASA uses the word ``effectiveness'' in its Report purely as a
    measure of how much momentum change can be imparted to the asteroid.
    e.g., in its ``Key Findings for Diverting a Potentially Hazardous
    Object,'' the first sentence of the first finding states ``Nuclear
    standoff explosions are assessed to be 10-100 times more effective than
    the non-nuclear alternatives analyzed in this study.'' The technical
    term for NASA's undefined word ``effectiveness'' in this instance is
    ``total impulse,'' i.e., the amount of momentum imparted to the
    asteroid in the process of the deflection.
        Without doubt the total impulse available is a key measure of any
    deflection concept. However all of the impulsive (i.e., relatively
    instantaneous as juxtaposed with slow) deflection techniques evaluated
    are, while quite powerful, highly uncertain with regard to predicting
    the precise total impulse delivered. Experts in the field estimate
    uncertainties ranging from factors of two to five or even higher in the
    resulting total impulse delivered by either the nuclear or kinetic
    impact deflection concepts.
        Certainly ``strength'' may well be needed in the deflection of an
    object on an impact trajectory. The first order of business is, without
    question, to ensure that the NEO is deflected sufficiently that it miss
    the planet.
        What NASA totally missed however is that whenever an asteroid
    passes near the Earth (or any planet) it passes through a region in
    which are scattered hundreds of small impact ``keyholes,'' small areas
    in Earth's proximity through which if the asteroid passes it will
    return within a few years and impact the Earth. Any deflected asteroid
    which misses the Earth must transit this minefield of impact keyholes.
        Because the percentage of space taken up by such keyholes is small
    compared with the space between them the probability of the NEO passing
    through one is fairly low. However the consequences of passing through
    such a keyhole are severe. Thus, whether or not a deflected NEO misses
    the keyholes cannot be left to chance. A successful deflection must
    therefore be defined as one which causes the potentially impacting
    asteroid to not only to miss the Earth but also to miss all impact
    keyholes. Without this constraint any deflecting agency would be
    limited to declaring, ``we successfully deflected the asteroid away
    from an impact with Earth. . . and it is unlikely that it will return
    for an impact any time soon.''
        A successful deflection requires both adequate strength and high
    precision. Immediately following an impulsive deflection the new orbit
    of the asteroid must be precisely determined and examined for a future
    keyhole transit. if headed for a keyhole then a small ``trim'' maneuver
    can be executed using a weak but precise ``slow push'' (as NASA refers
    to it) deflection to avoid that critical passage.
        This combination of imprecise strength and precise adjustment is
    both necessary and sufficient to declare to the world that a fully
    successful deflection has been achieved. NASA completely missed this
    essential point in its analysis.
        These two key flaws are illustrative of the quality of the analysis
    on deflection alternatives in the NASA Report. I again refer you to the
    attachments for greater detail.

    2. How should NASA now proceed on these issues?

        I believe that NASA should produce a supplement to its Report to
    Congress based on new knowledge which has come to light since it began
    its analysis. (Recommendation 2) The state of knowledge of the NEO
    deflection challenge is increasing very rapidly and NASA has not stayed
    abreast of recent developments. This is not entirely NASA's fault since
    it has no assigned responsibility in this critical area. Nevertheless
    given the Congressional request for an analysis of alternatives, and
    the urgent need for a legitimate understanding of these options, I urge
    that NASA revisit this matter. I list below, inter alia, a few
    suggestions in this regard.

            a)  NASA should re-examine the NEO deflection challenge
            utilizing the most likely set of threatening NEOs that we will
            likely confront. The lower bound of this cohort should lie in
            the range of the 1908 Tunguska event. (Note: This does not
            imply a change in the 140 meter search goal. In meeting the
            140-meter goal NASA will discover a large fraction of the
            Tunguska sized NEO cohort as well.)

            b)  NASA should examine the need for precision and control in
            the deflection process taking particular account of the role
            impact keyholes play during a deflection.

            c)  NASA should further review and analyze its current (and
            future) database of NEOs to determine the frequency with which
            close gravitational encounters occur between the time of NEO
            discovery and the time of potential impact. In the case where
            such encounters occur (e.g., Apophis, the most threatening NEO
            in the current database) analysis shows that a single mission
            can often be employed to both determine if an impact is indeed
            threatened and take ``slow push'' preventive action if
            necessary. We must understand this class of prospective impacts
            and capitalize on the potential for a simple and less costly
            deflection mission.

            d)  NASA should fully assess the value of a dual-band IR
            telescope in a Venus-like orbit for search and tracking
            purposes. NASA has already analyzed this instrument's search
            capability, but it should extend its thinking to evaluate how
            to use such an instrument to support our impact prevention
            capability.

            e)  NASA should correct its faulty analysis of the cost and
            technological readiness of the Gravity Tractor.

    3.  What needs to be done to mitigate the risks of potential NEO
                        impacts?

        There are two key actions to be taken that would make significant
    progress toward protecting the Earth from the potential devastation of
    NEO impacts. Neither of them is expensive yet both of them are
    extremely important, even urgent, in light of the anticipated rapid
    rise in the NEO discovery rate in the near future.

            a)  NASA should assign someone in its NEO Program to the
            specific task of thinking through, analyzing and understanding
            the NEO deflection challenge. (Recommendation 3) So long as the
            NASA effort, and therefore thinking, is restricted to the NEO
            discovery process only, the government will lack the critical
            information and understanding needed to protect the Earth from
            NEO impacts. There is critical linkage between the upstream
            process of NEO search and orbit analysis and the downstream
            information needed to deflect NEOs. Absent someone explicitly
            thinking this through we stand justly accused of focusing on
            numeric goals for the sake of meeting an abstract quota. I
            hasten to point out that NASA cannot make such an assignment
            without being given the explicit responsibility for this
            critical function.

            b)  NASA should validate a basic NEO deflection capability
            through the execution of a demonstration mission.
            (Recommendation 4) While deflection concepts can and indeed
            must first be worked out conceptually, in an endeavor as
            critical to public safety as deflecting an asteroid bound for
            an impact, our ultimate success in such a vital undertaking
            cannot depend solely on a paper analysis. A demonstration
            program can be performed on a non-threatening asteroid at a
            cost no more than that of a typical small scientific mission.
            This effort need not, and perhaps should not, be undertaken as
            a U.S. mission per se. The European Space Agency (ESA) has
            already performed the initial feasibility and design phase of
            such a mission (though it should be modified to validate the
            ``slow push'' component). Were an international partnership
            agreement negotiated a reasonable cost estimate for a complete
            NEO deflection demonstration campaign could be performed for
            about the cost of a single scientific mission.

    4.  What governance structures should be established to address
                        potential NEO threats?

        I believe this to be the single most important question of this
    hearing. Until and unless an explicit assignment of responsibility
    within government is made to protect the Earth from NEO impacts, no
    significant advances in our capability will be made, and the US public,
    and indeed the world public, will remain unnecessarily at risk.
        Ironically and somewhat counter intuitively, the full cost of
    assigning such responsibility and paying for its operations is almost
    vanishingly small. It is, nevertheless, a sobering responsibility, and
    an historic one. The very concept of being able to slightly alter the
    workings of the cosmos to enhance the survival of life on Earth is
    staggeringly bold. Yet this very capability lies within our technical
    means today. The missing element, the fatal missing element, is a
    governmental assignment of responsibility.
        I would break this charge into two logical pieces.

            a)  First it seems to me that there exists today a single
            logical entity that should be responsible for the analysis,
            design, manufacturing and testing of a NEO deflection
            capability. That entity is NASA. NASA is our national space
            agency and is clearly charged with the development of our
            national space capability. This is, I believe, a clear and
            obvious choice.

                NEO work in NASA is, however, administratively in an
            orphaned status. Protecting the Earth from NEO impacts is
            neither space science nor exploration, although there are
            elements of both involved. Protecting the Earth from NEO
            impacts is a public safety activity. Yet today within NASA and
            its supporting space science and exploration communities the
            strong perception is that a dollar spent on NEO work is a
            dollar taken from space science or exploration. This ``zero-sum
            game'' presumption cannot be allowed to persist. Yet until
            explicit responsibility and funding for NEO research, as a
            public safety responsibility, is assigned to NASA by the
            Congress, this terrible conflict will persist. I therefore
            recommend that the Congress expressly assign to NASA the
            technical development elements of protecting the Earth from NEO
            impacts as a public safety responsibility. (Recommendation 5)

            b)  The second element is considerably more challenging and
            controversial. That is, to which agency of government should
            fall the overall responsibility for protecting the Earth from
            this infrequent, but devastating natural hazard? This
            responsibility is greater than and somewhat separate from the
            technical issues discussed above.

                While we have not addressed this matter above I will simply
            state unequivocally that the NEO mitigation decision process
            and the policies embedded within it are inherently
            international. Any NEO deflection will necessarily shift risk,
            however temporarily, between people and property across the
            planet. As we move a NEO away from an Earth impact, we
            necessarily shift its impact point from one region to another
            until we complete the deflection.

                Given this characteristic, and I ask that you grant this
            arguendo, the response to a threatening NEO will involve
            complex and very sensitive international coordination and
            probably negotiation. This is a planetary challenge, not a
            national one. The policies, procedures, criteria, thresholds,
            and agreements which must be addressed are international
            political challenges and the U.S. involvement will place in the
            hands of the agency responsible the lives and property of the
            world's entire population.

                It would frankly be presumptuous of me to make a specific
            recommendation here. Obvious candidates for such a
            responsibility include the Department of Homeland Security
            (DHS), the Department of Defense (DOD), and of course NASA.
            Many other agencies will clearly need to be involved in the
            decision processes given the potential of evacuation, migration
            (including cross border), and potentially unprecedented
            property destruction.

                I therefore recommend that the Congress study the issue of
            overall governmental responsibility for protection of the Earth
            from NEO impacts, perhaps with the assistance of specialized
            policy entities, and ultimately hold public hearings to engage
            a wide perspective on the issue. (Recommendation 6)

        In closing I would suggest a personal perspective based on having
    spent the last six years of my life studying this issue. NEOs are part
    of nature. A NEO impact is a natural hazard in much the same way as are
    hurricanes, tsunamis, floods, etc. NEO impacts are deceptively
    infrequent, yet devastating at potentially unimaginable levels. NEOs
    are however not our enemies. We do not need to ``defend'' against NEOs,
    we need to protect ourselves from their occasional impact, as we do
    with other natural hazards.
        Unlike other natural hazards, however, NEO impacts can be predicted
    well ahead of time and actually prevented from occurring. If we live up
    to our responsibility, if we wisely use our amazing technology, and if
    we are mature enough, as a nation and as a community of nations, there
    may never again be a substantially damaging asteroid impact on the
    Earth. We have the ability to make ourselves safe from cosmic
    extinction. If we cannot manage to meet this challenge, we will, in my
    opinion, have failed to meet our evolutionary responsibility.
        Thank you.

                      Biography for Russell L. Schweickart

        Russell L. (Rusty) Schweickart is a retired business and government
    executive and serves today as Chairman of the Board of the B612
    Foundation. The organization, a non-profit private foundation,
    advocates the development of a space system to protect the Earth from
    future asteroid impacts. The Foundation's goal is ``to significantly
    alter the orbit of an asteroid, in a controlled manner, by 2015.''
        Schweickart is the founder and past president of the Association of
    Space Explorers (ASE), the international professional society of
    astronauts and cosmonauts. .He currently serves as Chairman of the
    ASE's Committee on Near-Earth Objects. The organization promotes the
    cooperative exploration and development of space and the use of space
    technology for human benefit. The ASE has a current membership of over
    390 astronauts and cosmonauts from 31 nations. The Association's first
    book, The Home Planet, with a preface by Schweickart, was published
    simultaneously in 10 nations in the Fall of 1988 and was an immediate
    international best seller.
        In 1987-88, Schweickart chaired the United States Antarctic Program
    Safety Review Panel for the Director of the National Science Foundation
    (NSF) in Washington, DC. The resulting report, Safety in Antarctica, a
    comprehensive on-site review of all U.S. activities in Antarctica, led
    to a restructuring of the program, increasing the safety of operations
    in that hazardous environment. At the request of the National Science
    Foundation, Schweickart also served on the 1997-1998 United States
    Antarctic Program Outside Review Panel, which reported to the White
    House (OSTP) and Congress on the future of U.S. facilities in
    Antarctica. The U.S.' Amundson-Scott South Pole station is currently
    being fully rebuilt as a result of this work.
        In 1977 Schweickart joined the staff of Governor Jerry Brown of
    California, and served in the Governor's office for two years as his
    assistant for science and technology. In 1979 Schweickart was appointed
    to the post of Commissioner of Energy for the State of California and
    served on the Commission for five and a half years. The Commission,
    which was chaired by Schweickart for three and a half years, was
    responsible for all aspects of energy regulation in the state other
    than rate setting, including energy demand forecasting, alternative
    energy development, power plant siting and energy performance
    regulation for appliances and buildings.
        Schweickart joined NASA as one of 14 astronauts named in October
    1963, the third group of astronauts selected. He served as lunar module
    pilot for Apollo 9, March 3-13, 1969, logging 241 hours in space. This
    was the third manned flight of the Apollo series and the first manned
    flight of the lunar module. During a 46 minute EVA Schweickart tested
    the portable life support backpack which was subsequently used on the
    lunar surface explorations. On the mission with Schweickart were
    commander James A. McDivitt and command module pilot David R. Scott.
        Schweickart served as backup commander for the first Skylab mission
    which flew in the Spring of 1973. Following the loss of the thermal
    shield during the launch of the Skylab vehicle, he assumed
    responsibility for the development of hardware and procedures
    associated with erecting the emergency solar shade and deployment of
    the jammed solar array wing, operations which transformed Skylab from
    an imminent disaster to a highly successful program.
        After the Skylab program, Schweickart went to NASA Headquarters in
    Washington, DC as Director of User Affairs in the Office of
    Applications. In this position he was responsible for transferring NASA
    technology to the outside world and working with technology users to
    bring an understanding of their needs into NASA.
        Prior to joining NASA, Schweickart was a research scientist at the
    Experimental Astronomy Laboratory of the Massachusetts Institute of
    Technology (MIT). His work at MIT involved research in upper
    atmospheric physics, star tracking and the stabilization of stellar
    images. His thesis for a master's degree at MIT was an experimental
    validation of theoretical models of stratospheric radiance.
        Schweickart served as a fighter pilot in the U.S. Air Force and the
    Massachusetts Air National Guard from 1956 to 1963. He has logged over
    4000 hours of flight time, including 3500 hours in high performance jet
    aircraft.
        Schweickart was awarded the NASA Distinguished Service Medal (1969)
    and the Federation Aeronautique Internationale De La Vaux Medal (1970)
    for his Apollo 9 flight. He also received the National Academy of
    Television Arts and Sciences Special Trustees Award (Emmy) in 1969 for
    transmitting the first live TV pictures from space. In 1973 Schweickart
    was awarded the NASA Exceptional Service Medal for his leadership role
    in the Skylab rescue efforts.
        He is a Fellow of the American Astronautical Society and the
    International Academy of Astronautics, and an Associate Fellow of the
    American Institute of Aeronautics and Astronautics. Schweickart is a
    Trustee and a Fellow of the California Academy of Sciences.
        Schweickart was born on 25 October 1935 in Neptune, NJ. He is
    married to Nancy Ramsey of West Hartford, CT. He has seven children and
    eleven grandchildren. He graduated from Manasquan High School, NJ;
    received his Bachelor of Science degree in 1956 and his Master of
    Science degree in 1963, both from the Massachusetts Institute of
    Technology.
        His hobbies include golf, bicycling, and hiking.

                                   Discussion

        Mr. Lampson. Thank you, sir, very much. Thank all of you,
    the whole panel. It is really been a pretty fascinating topic
    for us to be taking up.
        At this time, each Member will be given five minutes to
    question the panel, and I will yield myself, as Chairman, the
    first five minutes.

                Importance of Surveying Objects Larger Than 140m

        And Dr. Yeomans, is it correct that you pretty much agree
    with the importance of surveying all potentially hazardous
    objects, down to 140 meters in size?
        Dr. Yeomans. Yes. I think that is the next step. By doing
    so, by finding 90 percent of these objects, we would
    effectively reduce the risk of all Near-Earth Objects to Earth
    by 99 percent. Now, Rusty mentioned the smaller objects still,
    but that could be the subject of a third generation search. But
    the 140 meter and larger objects are primarily, necessarily the
    focus of the next survey.
        Mr. Lampson. Well, the Authorization Act of 2005 directs
    NASA to implement a program to catalog 90 percent of all the
    140 meter or larger NEOs by the end of 2020. Is that still a
    realistic goal, or should the scope or timetable be adjusted,
    and if so, what would you recommend that new goal to be?
        Dr. Yeomans. Well, I think the 2020 timeline was selected
    because we needed some sort of a metric to judge progress by,
    but it has been pointed out that the impact interval for a 140
    meter sized object is about 5,000 years, so my personal opinion
    would be that we could afford to wait another couple of years,
    and perhaps do the survey by the end of 2030 or thereabouts,
    and explore some options that would be easier and less
    expensive to carry out within that timeframe.

                     Risk of Changing the Project Timeline

        Mr. Lampson. Maybe our technology even would have grown
    more, and we will be able to do it more effectively, or at a
    lesser cost.
        Dr. Tyson indicates that the LSST could meet the 90 percent
    goal by 2026, at an average cost to NASA of about $10 million a
    year for 12 years. From a risk reduction standpoint, how
    serious would a 6-year delay in meeting that Congressional goal
    be, and would anybody else after that, after your comment,
    would anybody else like to make a comment on it?
        Dr. Tyson. I think that the risk reduction is significant,
    if one is able to go down to these small sizes. In 12 years, as
    opposed to 10 years, my personal opinion is the same as Don's.
    I think that one has to just get on with it and do these
    surveys, and if it takes 12 years instead of 10 years to reach
    90 percent, then we should just do that.
        Mr. Lampson. Dr. Yeomans, would you comment also, please?
        Dr. Yeomans. I agree with what Tony said. I would like to
    see, perhaps, an extension of our report to Congress, whereby a
    few options are looked at in far more detail, in a more
    rigorous fashion, and costing is done in a more rigorous
    fashion. And perhaps one of the options, one of the few options
    that would be examined, would be the LSST, working in
    cooperation with Pan-STARRS, and also one, perhaps two space-
    based options. Infrared surveys are still very effective, but
    that would be my suggestion.

                         Non-U.S. NEO Characterization

        Mr. Lampson. Anybody else want to make a comment on that
    before I ask my next question? Okay, let me go on, because we
    are going to get to all of you.
        Dr. Yeomans, what if any contributions are non-U.S.
    organizations or agencies providing to the detection, tracking,
    and characterization of NEOs?
        Dr. Yeomans. Well, as was pointed out, in terms of
    discovering them, NASA is doing the lion's share of the work,
    certainly more than 98 percent of all discoveries are by NASA-
    supported facilities. But there are international efforts
    underway to characterize these objects. Our colleagues in ESA,
    the European Space Agency, are making strides. The Japanese
    have a mission currently underway to visit a Near-Earth
    asteroid and bring a sample back, so that is important.
        We have a group at Pisa, Italy, that is also working with
    us very closely to determine independently impact probabilities
    for various objects, and so, we are constantly in touch with
    those folks to verify our results, and they are doing the same,
    and verifying their results with us, and if we come up with
    interesting objects like Apophis, for example, the object that
    will get very close to the Earth in 2029, we wait until we have
    verified our results with our colleagues in Italy before we
    make any formal announcements. So, that is working very well.

                   Increasing International NEO Collaboration

        Mr. Lampson. Is there more that should be done? And if so,
    what steps ought to be being taken? Can we build greater
    relationships, obviously through science we can, but is this
    one of those areas?
        Dr. Yeomans. I think it is. We should continue to encourage
    our international colleagues to participate more in the
    discovery area, more in the characterization area. And those
    activities are ongoing, through the Action Team that was
    mentioned, the UN Action Team 14, for the Peaceful Uses of
    Outer Space. So, those international discussions are going on.
    We certainly would appreciate more international efforts in
    these areas.
        Mr. Lampson. Dr. Green, what if any plans does NASA have to
    engage other nations or international entities in efforts to
    direct and characterize NEOs?
        Dr. Green. Currently, through our bilateral discussions
    with many of the other space agencies, such as ESA, such as the
    Canadian Space Agency, this is, indeed, a topic that comes up
    on every agenda. And indeed, we do see, as I mentioned in my
    testimony, growing international interest in this area. There
    are several missions that ESA has been studying, and most
    recently, in what they call Cosmic Visions, there is another
    mission called Marco Polo, that does have a much better chance
    now of making it through their budgetary process, that will
    also add information that is important for us.
        The Canadians will be launching a spacecraft called
    NEOSSat. We have been discussing about how it can be utilized,
    and making the data more available. So, indeed, in summary,
    that interest now is becoming more international. It is getting
    into the plans, future plans of our space agency partners. And
    as I mentioned, it is, indeed, a topic that we will continue to
    discuss and promote.
        Mr. Lampson. Anyone else want to--Mr. Schweickart.

                                 Public Safety

        Mr. Schweickart. Yes, Mr. Lampson. Let me simply second
    what has been said, but go a bit beyond it. I think one of the
    most important things that can come out of this hearing is to
    explicitly recognize that what we are discussing here is not
    science. What we are talking about here is public safety. This
    is not a subject in which relatively small amounts of money,
    frankly, should be traded off with the scientific research that
    goes on in NASA and elsewhere.
        We are talking here about two separate things, and they
    should not be mingled and seen as a zero-sum game, which is the
    way in which expenditures for issues related to Near-Earth
    Objects are seen by many people today. This is not a zero-sum
    game. We are talking about two things. One is science and
    exploration. Another is public safety. And we should not
    sacrifice public safety for science. These things are very
    important.
        I think when you go to the international community for
    additional support, it would be very helpful if the U.S., in
    its presentations in COPUOS, in the United Nations, were to
    appeal for additional support, on the basis that we are talking
    about, public safety on a worldwide basis. I think that may
    make a real difference.
        Thank you.
        Mr. Lampson. Thank you very much for your comments. Anyone
    else? Thank you very much. I will yield the next five minutes
    to Mr. Feeney, the Ranking Member.
        Mr. Feeney. Well, thank you, Mr. Chairman, and I am struck
    by your remark, Mr. Schweickart, that the way to appeal for
    international support on this is through safety and security,
    and I happen to agree with that. I mean, a lot of exploration,
    especially space exploration, is not a zero-sum game, but there
    are winners and losers. There are property rights issues. There
    are capabilities, in terms of geopolitics. But certainly, when
    you are talking about the potential to deflect a threat to the
    entire Earth, it seems to me that had the dinosaurs had the
    capability to deflect these things 65 million years ago, they
    might still be around. And maybe we can convince some of our
    international partners to bear some of the load; this is a win-
    win for everybody involved.

                           NEO Deflection Technology

        So, because there are so many fascinating parts of this,
    Dr. Yeomans, your remarks did not specifically talk about the
    technology that Mr. Schweickart did. You said that existing
    technologies can deflect an Earth-threatening asteroid if there
    is time. Can you describe those technologies, and can you give
    us your assessment of Mr. Schweickart's discussion of nuclear
    versus kinetic and the size of the objects?
        Dr. Yeomans. Well, there is basically two groups of
    mitigation techniques. There is the fast, flyby, or impacting
    techniques. You run into it, as we did with the Deep Impact
    mission, back in July of 2005, and simply slow the object down,
    if it is small enough to do that, and you have time enough, so
    that in 20 or 30 years time, when it was predicted to hit the
    Earth, its orbit would have been changed, so that it wouldn't
    hit. So, there is the fast or impulsive techniques, where you
    run into it, or if it is a large object, you would use nuclear
    explosives, perhaps.
        And then, there is the slow push techniques, where you
    rendezvous with the object, fly alongside it, and you do a
    number of techniques, possibly. A gravity tug has been
    suggested, where you just take your spacecraft, and put it up
    next to your asteroid, and just use the gravitational
    attraction between the two to move them just a little bit. Now,
    that is a technique that, as Rusty pointed out, can be used for
    so-called trim maneuvers. That is not what you would do
    primarily, but you would use that as a secondary device to
    alter the orbit of the object, in the event that your primary
    technique, the impulsive technique, perhaps didn't do the job,
    or knocked it into one of these subsequent keyholes that he
    talked about, where a subsequent impact would be likely.
        So, in any event, you need a spacecraft nearby to verify
    the result. That is clear, so--or that would be the optimal
    technique. So, again, you have to find them early to allow that
    to happen.
        Mr. Feeney. Mr. Schweickart, staying on the deflection
    capabilities for a second. You know, NASA says the slow push
    mitigation techniques are the most expensive, and we are
    furthest behind in technological capabilities. You seem to have
    a very different view from NASA's preference for a nuclear
    device.
        In terms of whether we use the slow push versus nuclear, in
    terms of where we could intercept a Near-Earth Object, is there
    a difference, in terms of when we can intercept the object in
    the two techniques, and what are the relative advantages and
    disadvantages, depending on size of the NEO?
        Mr. Schweickart. Yes, thank you very much for the question.
        First, let me endorse everything that Don just said in
    response to your earlier question. I don't think we have any
    daylight between us, frankly. I think the daylight is between
    what Don just said and what I also believe, and what the NASA
    report to Congress said. There is quite a bit of difference in
    there.
        Mr. Feeney. Let me say that NASA knows we have nuclear
    capabilities, and they know that they had a mission with one
    kilometer NEOs. What they did was to take the limited number of
    threats that they knew how to deal with very comfortably, but
    they avoided the more complex and more numerous problems. Is
    that maybe----
        Mr. Schweickart. Yes, I think that is a fairly good
    representation. Let me give you an idea that the nuclear, I
    would not, our organization would not suggest that nuclear can
    be ruled out. However, statistically, if you look at the
    probability of needing to use nuclear, as opposed to nonnuclear
    means, the frequency of that occurrence would become necessary
    about once every 100,000 years. So, you are talking about a
    very improbable frequency of need, and it is that issue which
    we have with what appeared in the NASA report.
        And let me emphasize, again, that as I stated in my report,
    that NASA in our discussions with them after they submitted
    their report, acknowledged that they did not fully understand
    this issue at the time the report was written. Don has now
    reflected, in fact, a current, and I believe a view which we
    totally support and agree with.
        Let me go to something which you mentioned, which is an
    extremely important, let me say misperception, and that is that
    in some way, what we are talking about is a slow push technique
    versus nuclear or kinetic impact. The thrust of my, no pun, the
    thrust of my testimony is to point out that both strength and
    precision are needed for a successful deflection when an
    asteroid is headed, let me say, for a direct impact with the
    Earth. You need the strength of a kinetic impact, in general or
    under exceptional conditions, a nuclear explosion, but you need
    to follow that up, potentially, if in fact, the deflection has
    now caused the asteroid to head for a keyhole which will cause
    it to come back, you need now this trim capability of the slow
    technique, gravity tractor or other slow technique, which can
    make a precision correction, to ensure that you don't have that
    asteroid coming back and hitting. Those two things are
    necessary for a successful deflection.
        Now, the one final thing which you mentioned, and we have
    not addressed it yet, but it is very important, and that is
    that NASA did not, in completing its report on the deflection
    capabilities, understand that the precision deflection that we
    are talking about could be done with existing space hardware.
    They used, for their analysis, the assumption of a very large,
    very complex spacecraft for a gravitational tractor, and that
    was incorrect. It was a misunderstanding, and in fact, that
    error should be corrected. Existing ordinary technology can be
    used, it is very mature, and it is very inexpensive, in fact.

                        Deflection of NEOs into Keyholes

        Mr. Feeney. Just very briefly, with my colleagues'
    indulgence. I am fascinated by these keyholes. So we are
    successful with the deflection for the time being, we miss, and
    it, for whatever reason, it comes into a keyhole. Don't we get
    a second shot to play ping pong with the thing?
        Mr. Schweickart. The basic sequence, which Don outlined,
    and which we advocate, is that any, first of all, we don't talk
    about a deflection mission. We should be talking about a
    deflection campaign, because one of the things that you need to
    have in place at the asteroid that you intend to deflect is a
    transponder, a spacecraft that has rendezvoused with it that
    has a transponder, so that we can do precise radio tracking.
    Number one, we need to determine, in fact, is that asteroid
    headed for an impact with the Earth. Number two, if it is, then
    you send up a deflection mission, a strong one, a kinetic
    impact, to make the primary deflection so that it misses the
    Earth.
        The next thing you do is go over to it with that same
    spacecraft which has now been observing that impact, to again
    precisely determine the success of that primary deflection, and
    very important, is it now going to pass through one of these
    nearby keyholes. If, and it is improbable, but if it is heading
    now for a keyhole, then you need to make a small adjustment in
    the deflection, using that same spacecraft with the transponder
    that has a gravity tractor capability, to make a small
    adjustment to make it miss that keyhole. Now, you have missed
    the Earth and all return keyholes, and therefore, you have a
    successful mission.
        That is a deflection campaign, involving basically two
    spacecraft.

                      More on International Collaboration

        Mr. Feeney. Mr. Rohrabacher.
        Mr. Rohrabacher. Thank you very much, and I have certainly
    found this hearing to be fascinating, as I expected it to be,
    and I would hope that we attract enough attention from the
    general public and from decision-makers, to understand that
    there are some things that we have to do, and I certainly agree
    with Rusty when he suggests that this is a safety issue and not
    a science issue. I would call it planetary defense, for lack of
    a better description, and I would hope that as we do enlist
    others, our European allies and the Japanese and others, I
    would hope that we also include the Russians in this equation
    as well. No one mentioned the Russians. I think a Russian-
    American partnership in this endeavor, I think they have a lot
    to contribute, and I think it would go a long way towards
    establishing the type of cooperation we need in space with the
    Russians.

           Probability of a 10km NEO Hitting Earth in the Near Future

        And with that, I see Arecibo, when we talked about, is a
    short-term issue in what we are talking about here. I mean,
    Arecibo is step number one, and we've got to get that done, and
    then, we are talking about this further threat. I understand
    that the object that hit the Earth and now is being credited
    with eliminating the dinosaurs happened about 65 million years
    ago, but I understand that they say that an object like that,
    odds-wise, would be about every 50 million years. So, are we
    not now in a cycle that would put us in the probability that
    there is another such object that may head to the Earth, not in
    the near future in terms of our lifetime, but in terms of the
    lifetime of the planet? Is that accurate to say?
        Dr. Yeomans. If I may respond. Statistically, the
    likelihood of an object that size happening, first of all, that
    was a 10 kilometer sized object, and there currently are no
    potentially hazardous asteroids that are that size. The largest
    is Toutatis, which is 5.4 kilometers, so we are not likely to
    see another dinosaur-like event.
        And the probabilities are such that an impact of an object
    of a particular size could happen tomorrow. It could happen in
    5,000 years. So, they are not really on cycles, as such.
        Mr. Rohrabacher. Well, but we are just talking about the
    levels of probability or likelihood, and people chart out what
    these objects are, you know, every so many thousand years, you
    can expect something to happen, just with the likelihood of the
    objects that are out. I think we are just talking about
    mathematical likelihood, and not necessarily anything else.

                                  Apophis NEO

        I would like to note that just a few years ago, there was a
    Near-Earth Object that passed between, or at least as close to
    the Earth as would have been between the Earth and the Moon, it
    was that close, and we didn't actually see it until it was
    actually past. And when you are talking about Apophis, it is a
    Near-Earth Object, that as we say, and I think Rusty mentioned
    it, in 2029 is when it will come close to the Earth.
        Is it true that we do not know if that object will, after
    it goes past the Earth the first time, that we do not know if
    the Earth's gravity will actually impact its trajectory to the
    point that it then becomes a threat? Is that correct?
        Dr. Yeomans. That is correct. Apophis will make a close
    approach on April 13, 2029, Friday the 13th.
        Mr. Rohrabacher. Friday the 13th.
        Dr. Yeomans. It is within 4.5 Earth radii of the surface,
    well within the geosynchronous altitude of our satellites.
        Mr. Rohrabacher. So, it is actually closer than some of our
    satellites.
        Dr. Yeomans. It is.
        Mr. Rohrabacher. And we don't know what the Earth's gravity
    will do to that trajectory, and so, it may, 10 years later, we
    may, as Rusty is talking about a campaign, we may be facing a
    second onslaught that may be even more dangerous 10 years
    later.
        Dr. Yeomans. Well, it has a one in 45,000 chance of passing
    through one of these keyholes that Rusty mentioned, and hitting
    us in April 13, 2036, but with the help of radar, Arecibo and
    Goldstone in 2013, we have a 95 percent chance of eliminating
    that threat altogether. So, it is a very unlikely situation,
    and one that we can drive to zero, probably.

                     Understanding the Threat Posed By NEOs

        Mr. Rohrabacher. Now, I will tell you that unlikely is, I
    remember the very first hearing we had on this, and I keep
    remembering, maybe it was one of you, we suggested the chances
    of anyone ever being hurt on this planet by a Near-Earth Object
    is, you know, about the same chance as you getting a royal
    straight flush in Las Vegas, and it just happens that I had
    gone to Las Vegas and got a royal straight flush once, and so,
    that is really actually what made it real for me, is when
    someone said that. And also, now, I have three children at home
    that are three years and three and one-half years old. We are
    not just talking about my lifetime or your lifetime, we are
    talking about their lifetime as well.
        So, I think that Rusty calculated right. However, let me
    just note, from what you said, Rusty, that you know, this is,
    when we are dealing with people, we have got to deal with this
    as a safety issue. It shouldn't be a tradeoff for science. That
    works internationally, maybe, and it may not work, in terms of
    getting the job done here. But that may be the only type of
    trading game that we can do here on Capitol Hill and still get
    the job done.
        And this issue is a priority for me. As far as I can see,
    we need to understand the threat, and that is what we are
    talking about right now. We don't even fully understand the
    threat yet. Then we need to know what we should do, which is a
    matter of discussion, and we have not even come close to that
    yet.

                             Future Responsibility

        And finally, we need to know who is going to be in charge
    of doing what needs to be done. And so we need a lot of
    discussion on this, and make those determinations. We are just
    now at the ``should we even take the steps necessary to
    understand the threat'' stage, and I think there is no question
    about that.
        Rusty, do you want to comment?
        Mr. Schweickart. Yes. I think it is very important, your
    last point, Congressman Rohrabacher. What we know now is that
    NASA is responsible. NASA is in charge of discovering,
    tracking, cataloging, et cetera, Near-Earth Objects. What we
    also know, but we don't seem to acknowledge, is that no one is
    in charge of protecting the Earth from impacts.
        Mr. Rohrabacher. Right.
        Mr. Schweickart. So, that next step is extremely important.
    At the moment, NASA has not yet adequately thought through the
    deflection issues. They have not, because they have not been
    told to. They do not have that responsibility. Until NASA or
    someone is given the responsibility to think through all of the
    implications and decisions and international cooperation, et
    cetera, for protecting the Earth from impacts, not just finding
    them, that job will not be done.
        So, this is extremely important.
        Mr. Rohrabacher. All right. Mr. Chairman, I would suggest
    that that is our job, that is our job as Congress, is to
    designate who is going to be responsible for that, what Rusty
    was just talking about, and we should do that in this session
    of Congress. It is that important an issue, and if another
    Near-Earth Object sneaks up on us, and we don't even know who
    we are going to, what procedure we are going to use to try to
    thwart the threat, then we haven't done our job.
        Thank you very much, and I appreciate you, Mr. Chairman,
    and yield back.
        Chairman Udall. Thank you, Mr. Rohrabacher. We, as you all
    know, have another vote underway. I am going to recess the
    Committee for a very short period of time, given it is one
    vote, and we will return as quickly as we can, and continue the
    questioning. We will have another round. I know Mr. Feeney
    intends to return, and I will see if Rohrabacher wants to ask
    another round of questions when we reconvene the Committee.
        So, the Committee stands in recess.
        [Whereupon, at 11:40 a.m., the Subcommittee was recessed,
    to reconvene at 12:08 p.m.]
        Chairman Udall. The hearing will reconvene. Again, I want
    to thank the panel for your forbearance with all the votes. We
    do, I believe, have another vote in an hour, so I understand
    that we can probably conclude the hearing in the hour we have
    left to us.

                          Potential NASA Partnerships

        At this time, the Chairman will yield himself five minutes.
    And I would like to focus, Dr. Green, on the testimony, as
    delivered by you and Dr. Pace, recommends that NASA continue
    the existing Spaceguard survey and also take advantage of
    opportunities using potential dual use telescopes and aircraft,
    and partner with other agencies, as feasible, to make progress
    toward achieving the legislative goal.
        We have heard today at least two examples of potential
    partnerships with other agencies supporting the planetary radar
    at Arecibo and funding the NEO operations of the LSST, that
    would make significant progress toward achieving the
    legislative goal for NEO detection and tracking at, I believe,
    a modest annual cost to NASA.
        What, specifically, is NASA doing to take advantage of
    either of these two potential partnership opportunities?
        Dr. Green. Indeed, we do want to continue on with our
    discussions with NSF for the use of the LSST. We have,
    certainly, an infrastructure in place with the Minor Planet
    Center, and our ability to utilize that data for NEO detection
    and orbit determination.
        Also, I had mentioned in my testimony the importance of
    using the Pan-STARRS system that the Air Force is currently
    putting into place, and in fact, we have provided them with a
    small amount of funds to be able to upgrade their software such
    that they are able to do some tracking, which is extremely
    important, and they have been very receptive. And that
    relationship is also quite strong.
        So, our intent is, indeed, to leverage these two important
    facilities as they are available, and as they come online.

                         NASA Funding NEO Partnerships

        Chairman Udall. Thank you, Dr. Green. To follow on, I
    wanted to ask if you have entered into any concrete discussions
    with NSF or DOE on potential partnerships addressing this
    Congressionally directed NEO survey task, and if not, why not?
        Dr. Green. Okay. Indeed, as I mentioned, we have concrete
    discussions with the Air Force, utilizing the Pan-STARRS
    system, and they are fully aware of what our intent is. NSF,
    indeed, is aware of our interest in using the LSST, and I
    anticipate that within this next year, that those discussions
    will become more firm, as we do understand how the funding
    becomes available for them to be able to actually build that
    system.
        Chairman Udall. Thank you, Dr. Green. To continue this line
    of inquiry, you mentioned that you are providing funding to the
    Air Force for Pan-STARRS. Did NASA do an analysis of the
    relative merits of providing NASA funding for Pan-STARRS,
    versus funding for the LSST or the Arecibo Planetary Radar,
    before deciding to give these resources to the Air Force? And
    if not, why not, and how much money is being provided, and
    where is it coming from in NASA?
        Dr. Green. The funding that we are utilizing to support
    small upgrades in the software for Pan-STARRS is a fairly
    modest amount. I would have to come back to the record to give
    you the exact amount, but it is within the $100,000 to $200,000
    range.
        [The information follows:]

                       Material Requested for the Record
        The NASA Near Earth Objects (NEO) Program started limited funding
    to the Pan-STARRS project in 2007 with a partial award to a proposal
    submitted to the program by the University of Hawaii, who manages the
    Pan-STARRS development for the Air Force. This partial award was a one-
    year grant to the University of Hawaii of $450,000. Any future funding
    will depend on the success of pending and future proposals Pan-STARRS
    submits to competitive opportunities of the NEO Program that NASA
    announces through its annual Research Opportunities in Space and Earth
    Sciences.

        Indeed, what we have arranged, with time, has been
    utilizing the funding for our NEO search opportunities with
    NSF, as Arecibo's telescope, by allowing us to increase the
    number of observers on utilizing that facility, with time. And
    then NSF taking over more of the operational activities. And
    then, we are following the National Academy report that did,
    indeed, suggest that NSF should support their ground-based
    facilities, and that allows us to better utilize the funding
    that we have available.
        Chairman Udall. Is NASA prepared to consider providing
    funding to Arecibo or the LSST project, as is being done with
    Pan-STARRS? And again, if not, why not, and if I can add a
    comment, why wouldn't it be logical to support those other
    activities, if you are prepared to support Pan-STARRS?
        Dr. Green. Well, currently, our arrangement with NSF has
    been to follow the NRC report that came out in 2001, which
    delineated roles and responsibilities for the funding of
    infrastructure. Indeed, we have worked with NSF in the past to
    be able to develop Arecibo capability for its radar use, and
    therefore, we leveraged that, as the rest of the community
    does, for that kind of research.
        So, with respect to that, I believe we have a working
    relationship is what it boils down to. NSF is funding their
    infrastructure capability. We are able to, with time, as I
    mentioned with Arecibo and also with the Pan-STARRS system,
    that the Air Force provide incrementally small amounts of funds
    to be able to meet and satisfy our requirements and needs, and
    that has worked extremely well, and we will continue to pursue
    that approach in the future.
        The LSST activity, of course, is one that needs to be
    resolved, in terms of whether they will have sufficient
    funding, and be able to put together the capability before we
    can begin to figure out how to work with them and leverage that
    system.
        Chairman Udall. Dr. Yeomans or anybody else on the panel,
    would you care to comment?
        Dr. Yeomans. I would just like to add that the modest
    funding to Pan-STARRS was done under a peer review process.
    They submitted a proposal to the Near-Earth Object Observations
    Program in NASA Headquarters, which is a modest program in and
    of itself, and it was thought at the time that their proposal
    was of sufficient merit that it should be awarded this modest
    sum. So, that was the process by which Pan-STARRS was funded at
    a modest level.
        Chairman Udall. Anybody else on the panel would like to
    comment? Dr. Campbell.
        Dr. Campbell. If I may, I would, just on the Arecibo
    situation, like to comment that perhaps the NSF hasn't read the
    NRC report, but it is my understanding they feel strongly that
    the solar system research, and especially research related to
    the NEO issue, is a NASA responsibility, and that they are very
    reluctant to provide additional funding to carry out that
    activity.
        Their plans to act on the recommendations of the Senior
    Review to reduce Arecibo's operating budget to $8 million, the
    concern, as Dr. Green just pointed out, is that NASA feels that
    they shouldn't really be supporting the operations of a
    National Science Foundation facility, as opposed to supporting
    some of the science which makes use of it. And what we are
    talking about here are the operational costs of the radar
    system at Arecibo.
        Chairman Udall. Dr. Tyson.

                          Using LSST for NEO Detection

        Dr. Tyson. Yes, thank you. I would like to make a couple of
    comments. First of all, the progress, we are on schedule on
    LSST towards a first light in 2014. We have a grant already
    from the National Science Foundation for R&D. We are about two-
    thirds of the way through that. We have put in, earlier this
    year, a construction grant, a construction proposal to the NSF.
    We just had this review, a very good positive result from that,
    and we are going towards readiness, into the National Science
    Board. So, we are on schedule, actually, for a 2014 first
    light.
        What is needed here to address this modified mission,
    beyond what we intend to do, this extra 15 percent of Near-
    Earth asteroid observing, is some extra support, starting now,
    with the collaborating with the computer science community on
    new ways of linking the small tracklets that one has when you
    take multiple images. Each one of these, LSST will see about
    150, each one of these small asteroids, about 150 times. You
    have to link all of these little tracks together.
        The problem is, the challenge is this. I just wish we had
    special glasses that we could put on when we look out at the
    night sky, and we only see the nearby Earth-threatening
    asteroids. Unfortunately, when you look out deeply in the night
    sky for things that are moving, you are confusion limited by
    this huge cloud of 10 million main belt asteroids, and you
    actually have to track all of those guys. You actually have to
    know each one of those orbits in order to separate out the
    Earth-threatening ones. So, that is the challenge, and that
    takes a lot of, millions of lines of computer code. There are
    some clever computer scientists out there that think they have
    a solution to some of those problems, and we need to get on
    with it. That is about $1 million a year, starting in next year
    or the year after, four or five years, and then we will have
    the software in place. And then, that extra 15 percent effort
    would cost us somewhere around $12 million a year during
    operations.

                       Radar Versus Optical NEO Detection

        I wanted to make a comment, if I may, about radar versus
    optical. I think you need both. One is not the replacement for
    the other. Radar is not a method of discovering all of these
    things, and winnowing down this 10 million objects into the few
    that are threatening. But once you have done that with optical,
    then radar is absolutely critical on the ones that you are
    really concerned with, to refine the orbit.

                          Importance of Arecibo Radar

        Chairman Udall. Mr. Schweickart.
        Mr. Schweickart. Yes, Chairman Udall. I would like to just
    pick up on where Tony left off, and give slightly different
    language, perhaps, or perspective on the Arecibo radar and its
    criticality.
        As Tony said, these two are not, I mean the Arecibo radar
    is not simply another thing to look for asteroids with. Number
    one, radar is not a good instrument to find or discover, to
    meet the quota that you guys have essentially dumped on NASA,
    you know, a certain number by a certain year. However, when
    what you are looking at or thinking about is protecting the
    Earth from impacts, picture yourself with a few hundred
    baseballs headed for your head. If you willingly take your pen
    and poke out one eye, you are now left with monocular vision.
    You don't have binocular vision. And if you want to get depth
    perception, you need both eyes. And yet, what we are doing is
    we are about to head into a serious decision-making process
    over the next 15 years on do we or do we not have to deflect
    something, and what you have done is, if you eliminate Arecibo,
    is you wiped out, willingly, your binocular vision.
        Now, that is extremely important. It is a little different
    way of thinking about the essential nature of Arecibo. It
    complements the optical view, and the most critical decisions
    we are going to make, or the most frequent ones, are the
    relatively small objects, which are numerous, which we are
    going to have to make decisions about. Those are the very ones
    that you get the least amount of data on, and where the Arecibo
    contribution is extremely critical. Because the next time you
    see that asteroid, it may be on final approach, and that first
    vision you get of it needs both optical and radar, you need
    both eyes.
        So, that is a different take on it. But it is not meeting
    the search goal which NASA has been assigned. It doesn't help
    in that, but it does help if what you are interested in is
    protecting the Earth.
        Chairman Udall. Thank you. That is very, very helpful to
    get that perspective.
        The Chair now recognizes, as we begin another round, the
    Ranking Member, Mr. Feeney.
        Mr. Feeney. Thank you, Mr. Chairman.

                             Radius of NEO Surveys

        This first question is for Dr. Tyson, Mr. Schweickart, Dr.
    Yeomans, and Dr. Campbell. The NASA recommendations are that we
    survey objects that come within .05 AU of Earth's orbit,
    instead of 1.3 AU, as required by the 2005 authorization. Do
    you agree or disagree with that recommendation, and why don't
    you give us some comments? If we need to change our
    recommendation, this is a place to start discussing it.
        Dr. Tyson. Congressman, I do agree with that. If you are
    calculating, if you are interested in, as I think we are,
    completeness in a survey of Earth-threatening objects, then you
    should have a survey of Earth-threatening objects, and those
    are the ones that come within----
        Mr. Feeney. Is .05 the number? Do you think that is a
    reasonable number?
        Dr. Tyson. That is right.
        Mr. Feeney. Okay.
        Dr. Tyson. I agree with that.

                   Ramifications of an Asteroid Hitting Earth

        Mr. Feeney. Okay. And no dissension? Okay. If anybody has
    an opinion, they agree with you, Dr. Tyson. I want to get an
    idea of the potential ramifications from a strike of Earth. A
    couple of months ago, we had a one meter object strike in Peru,
    roughly. We think it created about a 13 meter crater. Is that
    impact, I mean, if I am looking at a 100 meter object, am I
    looking at, you know, 1.3 kilometer crater? If I am looking at
    a kilometer object, am I looking at, you know, 13 kilometers?
        And outside the actual kinetic strike, and the damage done
    by things being broken apart by the actual collision, are there
    other things, like radiation or heat, or damages that would
    impact the environment or humans? This is for anybody who
    wishes to----
        Mr. Schweickart. Mr. Feeney, a relatively easy number is a
    100 meter object is about 100 megatons of explosive energy, or
    picture it as 100 one megaton nuclear bombs going off in one
    place without the radiation, without the nuclear radiation
    issue. But the explosive force is tremendous. Now, the other
    effects, I mean, the detailed effects of shock and that sort of
    thing, or even if there is a crater in the ground, are not as
    significant. When you talk about an explosion in the low
    atmosphere equivalent to 100 megatons, the impact on the ground
    is tremendous. The Tunguska event is thought today to have been
    about a five megaton explosion.
        Mr. Feeney. That was in 1908?
        Mr. Schweickart. 1908. We are celebrating the hundredth
    anniversary of that event next year, celebrating----
        Mr. Feeney. We are very familiar with floods and hurricanes
    in Florida. We refer to things as a 10 year event, a 20 year
    event, a 100 year event. What was the 1908 event, in your
    estimate? Is that one in 5,000 years, one in 100?
        Mr. Schweickart. Well, it is about a one in 600 to 800 year
    event, something like that. The size estimates have recently
    come down, so the frequency at which it occurs has gone up
    slightly. But I think the point is that that explosion, which
    flattened 2,000 square kilometers of forest and set them afire
    in Siberia. Luckily, it didn't kill anyone, maybe one person,
    that was only about a five megaton event, and it never got to
    the ground, there is no crater. But the impact would have wiped
    out all of London or Moscow or Washington, D.C., or any other
    city, had it unfortunately come, or exploded over one of those
    cities.
        So, the impact of these things does not necessitate a
    crater in the ground, but they are extremely powerful, even
    down to objects as small as, say, 40, 45 meters in diameter.
        Mr. Feeney. Dr. Tyson.
        Dr. Tyson. Yes. I would like to point out that it certainly
    would ruin my afternoon if one of these things hit close to my
    house. But most of the Earth's surface is covered by water, and
    studies of the actual physical damage from objects that are
    less than about a few hundred meters in size come really from
    the tidal waves that are set off when these objects would hit
    the ocean. There is much more danger that all coastal cities
    would experience a huge tsunami from such objects.
        The actual physics of what happens with larger objects is
    different. They are so large, these several kilometer size
    rocks are so large that they actually go down to the bottom,
    all the way through the water, and punch a hole into the ocean
    floor, and put all of that mud up into the stratosphere,
    creating nuclear winter. It is a very different scenario. So,
    for these smaller objects, it is a different and a somewhat
    scarier scenario, because there are so many more of them. As
    somebody pointed out, there is a factor of 100 more of these
    things. And there is a problem with, you know, I have a problem
    with probability. You know, you can say----
        Mr. Feeney. Probably.
        Dr. Tyson. Well, most likely. You can say that, well,
    actually, maybe we should spend $1 million on something else,
    because actually, the probability of this is rather low. But if
    a 100 meter object could be on its way towards Earth right now,
    and hit next week, for example, even though its probability,
    the probability per unit time is very low. So, I think what we
    need to do is to get on with these discovery surveys, which
    find virtually all of the Earth-threatening asteroids, and find
    their orbits, and then it changes the whole equation.
        Mr. Feeney. Thank you, Mr. Chairman. I yield back.
        Chairman Udall. Thank you. I am not sure, Dr. Tyson, you
    ruined my afternoon with that image, but that is a very
    powerful image and very compelling reason to do the work we are
    talking about here today.
        The Chairman recognizes the gentleman from California, Mr.
    Rohrabacher.
        Mr. Rohrabacher. Let us see. It is going to create a huge
    wave. I think I am the only surfer on this panel. One hand, we
    got another one here. All right.
        Now, let me see if I have got this right, Rusty, that the
    one, the object that exploded over this, was it Tunguska?
        Mr. Schweickart. Tunguska, yes, sir.
        Mr. Rohrabacher. Okay, was only the equivalent of a five
    megaton? And the one----
        Mr. Schweickart. Yes, sir. The most recent analytic work at
    Los Alamos indicates it was about five megatons, about 45
    meters.
        Mr. Rohrabacher. And you are saying the ones we are looking
    for are 140, would be the equivalent of 140 megatons, if it is
    a 140 meter object. Is that right?
        Mr. Schweickart. Approximately, yes, sir.

                             NEO Survey Objectives

        Mr. Rohrabacher. So, you are talking about something that
    would be 100 times more powerful than the one at Tunguska, is
    what we are just trying to observe?
        Mr. Schweickart. Yes, sir. That is correct. But let me
    emphasize, sir, that the 140 meter search goal is, in fact, at
    this time, the correct goal. Because, among other things, it is
    extremely difficult to find things as you get smaller and
    smaller. So 140 meters is a good goal, and in the process of
    finding 90 percent of the 140 meter objects, we are also going
    to find something on the order of 40 to 50 percent of the
    objects down to 45 or 50 meters. So, we will not have, let me
    say, a complete survey of those things which can do serious
    damage on the ground, but we will learn a great deal about them
    in the process of meeting this appropriate goal.
        Mr. Rohrabacher. Right. From what you said, we are talking
    about a huge potential destructive power. I mean, we are
    talking about something beyond, I think, the imagination of any
    of us here. What is the estimate of the number of undiscovered
    asteroids that are of 140 meter range? How many have we yet to
    discover? What are we talking about?
        Mr. Schweickart. Don has probably got the best number,
    but----
        Dr. Yeomans. The 140 meter sized objects, we think there is
    approximately 20,000 that are in the category of potentially
    hazardous asteroids, and we have discovered less than four
    percent of them.
        Mr. Rohrabacher. So, there are 20,000, and we have actually
    charted only about four percent of them? And it is 100 times
    stronger than what flattened all of that territory up in
    Russia?
        Dr. Yeomans. It is like your statement, sir, ignorance is
    bliss.
        Mr. Rohrabacher. Yes, sir. Dr. Tyson.
        Dr. Tyson. Just to add a data point. It is hard to
    comprehend the destructive force of something like this, but a
    300 meter asteroid, of which there are many, has the potential
    to wipe out entire countries.
        Mr. Rohrabacher. Well, obviously, there is a need for us to
    be prepared to try to do what we could. If we could mitigate
    that, we are talking about minimal expense, as compared to
    what, the cost of actually having to absorb this type of
    damage.

                       Planetary Defense Responsibilities

        I would like to talk a little bit about that. Who should be
    in charge? NASA is obviously involved with the efforts of
    identifying this, and with the Jet Propulsion Laboratory, and
    the assets that we are talking about. And NASA has been tasked
    with this. Once we determine that there is a threat, Rusty is
    suggesting that this is no longer a science issue. This is a
    defense issue at that point. Should the Defense Department be
    the ones who are then tasked with immediately taking over
    responsibility? Do you have some ideas as to who should, then,
    be the entity that is responsible for planetary defense? To
    start with NASA, and then work our way down.
        Dr. Pace. Thank you, sir. Well, as you probably know, there
    is no one who is tasked specifically with that responsibility
    right now. That is not a settled policy question. And I think
    it is also fair to say that it would be something that would
    take the resources and capabilities of multiple federal
    agencies, if they were to be so tasked.
        So, as Mr. Schweickart says about, these things are safety
    issues versus sort of science issues, I would also submit this
    is really a policy question as to where you want to assign
    policy responsibilities for this, and what sort of importance
    you want to give to it.
        I think NASA's traditional role certainly is stronger in
    the science and in the technology side of it, and therefore,
    you know, it wouldn't be obvious that we would be the lead
    agency for something like that, although if so directed, we
    would certainly participate with other federal agencies who
    were assigned.
        Mr. Rohrabacher. Does anyone else have a thought on that?
        Dr. Tyson. Mr. Rohrabacher, I would like to comment just a
    bit, and I thank you very much for highlighting that issue,
    because as I said, I believe this is really the most important
    single issue before the world, frankly. It is not only the
    United States, the Congress, and the Administration, but every,
    this is a global issue. It is not a national issue.
        Mr. Rohrabacher. Well, the first part of it is, are we
    going to do what is necessary to identify the threat, and then,
    the issue is who is going to do it?
        Dr. Tyson. Right. And I think that the identification of
    the threat has been relatively well dealt with. NASA has
    explicit responsibility, in terms of discovering. The
    identification of a threat comes right up to the point of
    warning, and issuing warnings has not been assigned to anyone,
    including NASA. So, that assignment has not been made.
        And I think that, in fact, it probably was avoided at the
    time, several years ago, because of this fundamental policy
    question. Who is to make these large international policy
    decisions, and I think that it is important that we look at the
    logic of it, and who should be involved? NASA clearly is the
    world's premier agency for developing and testing and
    demonstrating space capability, and space capability is the
    sine qua non of protecting the Earth against asteroid impacts.
        However, the policy issues are a larger issue, which
    involves cooperation between nations, agreements, tradeoffs of
    risk and many, many other things. And so, the policy issue is
    somewhat separable. Now, the Department of Homeland Security,
    it would seem, on plain reading of the language, might be one
    logical agency. The Department of Defense is clearly another
    potential agency, and NASA itself has many international
    responsibilities, for example, the International Space Station,
    in which it makes policy decisions on behalf of the Nation. So,
    to me, those three agencies are the prime candidates.
        I, frankly, because of the need for international
    cooperation and worldwide public confidence, would argue
    against the Department of Defense being the principal agency.
    The Department of Homeland Security certainly has a large
    responsibility, but it seems to me that the Congress needs to
    hold hearings to allow many, many people and perspectives and
    issues to be openly aired in this regard. But it is extremely
    important, because these international decisions are being
    forced on us by the very search programs that we have been
    talking about.
        In the next 10 to 15 years, we are going to discover
    hundreds of thousands of asteroids, and some of them, probably
    in the hundreds, will look as though they are headed for an
    impact. And somebody is going to have to make a decision,
    within the next 15 years, of do we or do we not take protective
    action?
        Now, those decisions are going to involve tradeoffs between
    nations and national policy issues, and it seems to me we need
    to get on with this critical decision, so that we are in a
    place to contribute.
        Mr. Rohrabacher. Thank you very much, and Mr. Chairman, I
    appreciate your holding this hearing, and I would like to
    personally thank the witnesses. This has been very
    illuminating, if not hair-raising. Thank you.
        Chairman Udall. I thank the gentleman from California, and
    I know within his political party and his circles, there is a
    lot of debate about the prefix NEO, and to which words you then
    apply it, but since Mr. Rohrabacher may be more of a neo-
    internationalist now than he perhaps has been in the past, when
    it comes to supporting a worldwide effort to make sure that the
    planet doesn't suffer from one of these impacts.

                           Goldstone Antenna Upgrades

        We are approaching another vote. I would like to ask a
    couple of additional questions of the panel, and then, we will,
    my questions will conclude the hearing. And I wanted to start
    with Dr. Green. NASA is planning to replace the existing deep
    space antennas at Goldstone with an upgraded system. Will NASA
    maintain the current planetary radar capability at Goldstone as
    part of the upgrade, and if not, why not?
        Dr. Green. Indeed, the organization in NASA that manages
    the Deep Space Network is the Space Operations Mission
    Directorate. They have the responsibility for developing an
    evolutionary plan for that system. It is used for
    communications, in addition to the science that we utilize that
    system for, and our radar requirements have been given to that
    organization as they develop their plan. In the near future, we
    anticipate seeing those requirements met in the newly
    redesigned Deep Space Network.
        Chairman Udall. Dr. Yeomans, how important is it?
        Dr. Yeomans. How important is it to maintain the radar with
    the DSN? I think it is very important. As was mentioned by a
    number of folks on the panel here, the Goldstone radar and the
    Arecibo radar are the only two we have, in terms of planetary
    observations, and they are very complementary. Goldstone covers
    a large area of sky. It can actually track the objects, whereas
    Arecibo is fixed, and can track 20 degrees on either side of
    directly overhead, so very often, an object will come into the
    Arecibo window, pass out of it, and pass into the Goldstone
    window and vice versa. So, it is important to keep both of
    these facilities robust.

                  Future Steps in NEO Detection and Deflection

        Chairman Udall. I would like to follow another line of
    questioning, but start with Dr. Yeomans again, and just give
    the panel a heads-up, and invite each one of you to comment
    before we conclude the hearing. And the focus will be where do
    we go from here? NASA submitted its report to Congress on
    options for the expanded NEO program for approaches to deflect
    NEOs.
        What do you believe, Dr. Yeomans, the relative priority for
    resources should be between NEO detection, tracking,
    cataloging, characterizing, and development of deflection
    approaches? In other words, what is most important to do next,
    and what specifically should NASA do next? Easy question, I
    know.
        Dr. Yeomans. Well, I am a bit biased. We have to find them
    early was my first, second, and third priority. And I do think
    finding them is the first priority. Obviously, we can't
    mitigate if we don't find them. We can't characterize if we
    don't find them.
        Having said that, we do need to characterize, because there
    is an enormous diversity amongst Near-Earth asteroids. They
    range all the way from a fluffy, wimpy, ex-cometary fluff ball
    to a rubble pile, to a slab of solid rock, to a slab of solid
    iron. So, you wouldn't mitigate each of those objects with the
    same technique, perhaps. So, we do need to characterize these
    objects, and we do need to at least study techniques for
    mitigation. There is computer simulation work that needs to be
    done to understand how an impact or an explosion would interact
    with a rubble pile, with a slab of iron. So, we do need to
    understand the mitigation and the characterization, but I think
    discovery is still the most important.

                             Orbital Determination

        Chairman Udall. Dr. Campbell, Dr. Tyson, Mr. Schweickart in
    turn, would you each like to comment on the question of
    priorities?
        Dr. Campbell. I think there is little doubt that discovery
    is the most important thing. If you haven't found them, you
    certainly can't track them and characterize them. It is clear,
    though, that there is little point in just making a catalog of
    a lot of objects in the sky, with poorly defined orbits. And
    therefore, I think that the two, orbit determination and
    discovery have to go hand-in-hand. And it seems to me the most
    important thing to do is to cull the number of objects that you
    have found as quickly as possible, so that you can actually
    concentrate on the ones that actually do pose a threat. We have
    already got thousands of potential objects here, we are going
    to be finding tens of thousands. We need to know which ones of
    these are a potential threat to Earth, and for the very
    smallest objects, we have potentially very little time to do
    that, in terms of the fact that they will be rather close to
    the Earth in orbits, and pass rather quickly, and not be
    detectable in the future.
        Chairman Udall. Dr. Tyson.
        Dr. Tyson. Thank you, Chairman. Discovery involves
    obtaining orbits. You can find a rock that is in the sky and
    then lose it, and it is of no use, and that doesn't count as a
    discovery. So, with LSST, one sees each one of these asteroids
    100 to 200 times, even more. So, it is possible to derive a
    pretty good orbit for those, and distinguish them from the
    background.
        So, that facility would get orbits for the Earth-
    threatening, so-called potentially hazardous asteroids. What is
    not widely known is that we observe the whole sky every several
    nights. We just repeat the whole sky every several nights,
    often in a different color band. So, we have a huge amount of
    color information in a six color system on each one of these
    Earth-threatening asteroids, and that, it turns out, as you
    might imagine, tells you a fair amount of information about the
    character of its surface and what it is made out of. So, we
    will gain some knowledge for characterization as well from this
    data.
        But I think we need, actually, the bottom line, I think, is
    we need to start this process of discovery. I agree with Don
    that one has to actually discover these things and get their
    orbits first, and that involves a multi-agency cooperation in
    these new facilities. I am thinking of the Department of Energy
    Office of Science, NASA, and the National Science Foundation.
        Chairman Udall. Mr. Schweickart.

                        More on Detection and Deflection

        Mr. Schweickart. Yes, Mr. Chairman. Thank you.
        I would like to suggest that your, the way in which you
    have posed the question is somewhat purist, I guess I would use
    the word. Like most things in life, we are confronted with
    things which are, they can be posited as either/or, but the
    reality is that they are usually not, and I would suggest that
    this is the case here.
        There is absolutely no question that finding them is
    absolutely the highest priority. Finding them early is very
    critical. At the same time, the most important thing to keep in
    mind is that we are finding them in order to protect the Earth
    from impacts, and so, I would also suggest that at the same
    time that we are spending money on finding them, we can also
    direct JPL or NASA to put one or two people to thinking about
    and working through and understanding the ultimate issue of
    protecting the Earth, mitigating ones that would be coming at
    us. And right now, unfortunately, that additional task of
    thinking through the deflection issue is not there.
        And all that takes is a clever person, which JPL has lots
    of, frankly, thinking about it. But right now, no one is
    assigned to that, because their job is to find them. And so, I
    suggest that we do both. And I don't think it's either/or.
        Chairman Udall. Knowing your history, and also having
    viewed with Mr. Feeney the movie Armageddon, I am sure you
    would be willing to volunteer for one of those missions,
    because the spirit is still willing.
        Thank you.
        Mr. Schweickart. Well, luckily, we don't have to have a
    human mission to one of these things.
        Chairman Udall. Thank you again for your testimony, for
    appearing here today. I want to turn to the representatives of
    NASA and Dr. Green and Dr. Pace. Would you care to comment as
    well, and well, you will have the final word today.
        Dr. Pace. Yes, I just wanted to address a point that any of
    these sort of mitigation techniques that one would want to use,
    of course, depends on the situation. As I said, many, many of
    these different objects have different technical
    characteristics, and different mitigation techniques may be
    appropriate.
        And so, in that regard, I just, I wanted to go back and
    clarify one point, that our report, I hope, did not give the
    impression that we had a preference for use of nuclear
    explosives. So, those are simply one of the items in the
    toolkit, and people can disagree over whether it is appropriate
    or not, depending on the situation. I just want to stress that
    we did not want to express a preference.
        The second thing is that we are trying to not only find
    objects, and obviously, more can be done, but that
    characterizing these objects is really also part of our science
    program. The missions, such as Dawn, that are being done, our
    international cooperation, what we learn about these objects
    with our science missions, we think is also directly helpful,
    should and if a mitigation mission ever be necessary.
        And then, finally, I wanted to agree with Dr. Tyson's point
    about the importance of turning a probabilistic threat into a
    deterministic one. That is, with a survey effort, and one can
    go faster or slower, depending on available resources, that one
    can get to a point where you know where these things are, and
    whether or not you have thousands of threats, hundreds of
    threats, one, or none. And that is also achievable. Progress is
    being made in ground-based optical telescopes at an amazing
    rate. LSST is one particularly notable one. And that if we
    simply proceed on the path we are on, we will, in fact, get
    good survey information. We will get good characterization of
    objects with our existing science program, and make progress,
    you know, toward the legislative goal.
        Thank you.
        Chairman Udall. Dr. Green, did you have anything else to
    add?

                       Importance of NEO Characterization

        Dr. Green. I certainly would echo a number of things that
    have been stated here. We know enough about the asteroids to
    know that not all are created equal. They are very
    heterogeneous, not only in composition in size, but also in
    their structure. Some are rubble piles. Some are, indeed, irons
    and quite different in shapes. And therefore, that
    characterization aspects, which is important from the
    scientific point of view, understanding their origin and their
    evolution, is extremely important for any, the next step, which
    would be consideration of mitigation, provided we understand
    that they are potentially hazardous objects, and when they
    might pose an important threat to us.
        So, I believe we have started that first baby step. We are
    moving out with existing assets. And we are excited about the
    near-term future, with new assets coming online. We will
    definitely step up our effort, in terms of utilizing those, and
    I believe, as we learn more about them, both from in situ
    observations, but continuing to utilize our radar facilities,
    not only in NASA, but we sincerely hope that NSF will continue
    to support the Arecibo radar, that that will enable us to then
    take more of those steps, which will lead up to some sort of
    mitigation information necessary to avoid these hazards in the
    future.
        Chairman Udall. Thank you, Dr. Green. I think I speak on
    behalf of Congressman Feeney, the Ranking Member, in offering
    my thanks to all of you for taking your valuable time today to
    appear before us, both panels, including Congressman Fortuno,
    have been very, very useful to the Committee.
        I would like to make note if there is no objection, the
    record will remain open for additional statements from the
    Members, for answers to any followup questions the Subcommittee
    may ask of you all on the panel. Without objection, so ordered.
        The hearing is now adjourned.
        [Whereupon, at 12:50 p.m., the Subcommittee was adjourned.]

                                  Appendix 1:

                                  ----------

                       Answers to Post-Hearing Questions

    Responses by James L. Green, Director, Planetary Science Division,
            Science Mission Directorate, National Aeronautics and Space
            Administration (NASA)

    Questions submitted by Chairman Mark Udall

    Q1.  NASA submitted a 2007 report to Congress on NEO search and
    deflection options, but the report doesn't provide a recommended
    option, as required in the 2005 NASA Authorization Act. What approach
    does NASA recommend that complies with the legislated mandate and what
    steps have NASA taken to begin implementing any of the options
    identified in the report?

    A1. NASA will look for opportunities using potential dual-use
    telescopes and spacecraft--and partner with other agencies as
    feasible--to attempt to achieve the Congressional goal outlined in
    Section 321 of the NASA Authorization Act of 2005 (P.L. 109-155). The
    Agency has already begun work with Pan-STARRS to ensure its capability
    for use in the NEO survey effort, and is beginning work to assess what
    might be done with the Wide-field Infrared Survey Explorer (WISE), and
    to upgrade the capabilities of the Minor Planet Center (MPC).

    Q1a.  NASA's report to Congress mentions search options that would rely
    on planned ground-based telescopes that have been proposed for
    development under the auspices of other agencies. What role, if any,
    should NASA play in supporting the NEO-related operations of those
    telescopes? What alternatives exist if those assets are not funded and
    developed?

    A1a. Maximizing use of the Pan-STARRS and eventually the LSST, if they
    are developed by other agencies, may be a very cost-effective way for
    NASA (though perhaps not the Federal Government as a whole) to meet the
    90 percent goal, though not on the timeline outlined in Section 321 of
    the NASA Authorization Act of 2005 (P.L. 109-155). At the present time
    NASA does not have a commitment from the sponsoring agencies that the
    assets will be developed. However, the Agency has begun discussions
    with the University of Hawaii regarding use of the Pan-STARRS prototype
    telescope and will continue to monitor its further development, as well
    as the possible eventual support of LSST by the National Science
    Foundation, in order to insert at the appropriate time capabilities and
    commitments for their use in the NEO survey effort. In fact, LSST (or a
    generic equivalent) is expected to be reprioritized by the National
    Academies in its upcoming astronomy and astrophysics decadal survey
    process, and this report will play a significant role in future
    prospects for LSST within the Foundation's broader set of priorities.

    Q2.  Dr. Yeomans testified that optical observations alone are often
    not ``accurate enough to immediately rule out a future Earth impact''
    once a potentially hazardous asteroid is detected. Dr. Campbell
    testified that the Goldstone antenna alone would be unlikely to fill
    the void if Arecibo were to be shut down. What specifically are NASA's
    plans for calculating the risk of potentially hazardous objects in a
    timely fashion, especially given the expected increase in NEOs detected
    from an expanded survey with Pan-STARRS or LSST? Do those plans involve
    either Arecibo or Goldstone?

    A2. The Spaceguard System, which was setup and supported by NASA, will
    continue to process NEO observations for impact prediction analysis by
    the Agency's NEO Program Office in a near real-time manner through the
    established procedures with the Minor Planet Center of obtaining timely
    follow-up optical observations and reviewing archived data and
    photographic records for ``pre-discovery observations.'' As the
    proposed expanded survey efforts (potentially with assets like Pan-
    STARRS and LSST) come on line to detect significantly fainter (i.e.,
    smaller) NEOs, these types of instruments will have the coverage
    capacity to essentially be responsible for obtaining their own optical
    follow-up observations.
        Although the radar capabilities of both Arecibo and Goldstone are
    able to provide precise refinement of NEO orbits, their observations
    are only available on a limited subset of NEOs--those that happen to be
    passing close enough to Earth to be within their range. NASA will use
    these observations when available, but by far the majority of NEOs
    orbits must still be determined via optical observations. Once a NEO
    has been initially detected and its approximate position determined, a
    whole host of other optical assets can be brought to bear on that NEO's
    location to determine the orbit as precisely as our orbit models allow.
    Over time periods significantly smaller than the average impact rate (a
    few years versus hundreds of years between significant impacts) a
    collection of optical observations will approach the accuracy that can
    be obtained via radar observations.

    Q3.  What are the requirements for data management to support the
    expanded Survey? How big a job is it likely to be?

    A3. Data throughput required as an expanded Survey reaches peak
    discovery productivity is estimated to reach as much as 100 times the
    current discovery and observation rates, with the associated needs for
    expanded data archives. The current Minor Planet Center computer
    systems are at least two generations obsolete, and will therefore need
    to be upgraded. However, the anticipated capabilities needed are well
    within the capabilities of modern desktop computer network systems.

    Q3a.  Your testimony indicates that NASA has started to evaluate the
    needs of the Minor Planet Center to accommodate the increase in
    detection that will result from an expanded survey. What, in specific
    terms, are NASA's plans for the Minor Planet Center and any changes
    that may be required to support the expanded survey? What, if any,
    costs are associated with those plans? How do those plans relate to
    options on data management presented in the report to Congress?

    A3a. In 2008, NASA's Science Mission Directorate plans to solicit for
    proposals from the small Solar System bodies community for management
    and operations of the Minor Planet Center--first to modernize the
    current computer systems and operations, and then to accommodate
    expanded data throughput for an anticipated expansion of the Survey
    effort. Costs will be determined based on the proposals received, but
    NASA does not anticipate costs beyond $1.0 million per year initially.
    Later options may look at back-up facility needs. This approach most
    closely relates to the ``Scale Existing Data Management Systems''
    alternative outlined in the NASA report on NEOs submitted to Congress
    in March 2007.

    Q3b.  Does NASA have any plans to compete the data management task for
    the expanded search?

    A3b. The Minor Planet Center solicitation will be a full and open
    competition.

    Q4.  The European Space Agency (ESA) has conducted a study for a
    mission (Don Quixote) that would test NEO deflection technologies. Has
    ESA expressed any interest in international cooperation on a mission,
    if it were to go forward? If so, has NASA explored the possibility of
    contributing?

    A4. The Don Quixote mission concept has been discussed at bilateral
    meetings with ESA as a potential area for cooperation. However, NASA
    understands that further development of this mission has been placed on
    hold by ESA.

    Q4a.  Your testimony noted that ``ESA has been studying . . . another
    mission called Marco Polo, that does have a much better chance now of
    making it through their budgetary process, that will also add
    information that is important for us.'' Could you please describe the
    potential Marco Polo mission and how it would benefit NASA's NEO search
    and/or the characterization of NEO's? What is the status of any
    discussions between NASA and ESA on collaboration or access to data
    from this potential mission?

    A4a. Marco Polo is a proposed near-Earth object sample return mission
    to a primitive asteroid whose objective is to return samples that are
    otherwise not available among known meteorites. Primitive bodies are
    leftover building blocks from the earliest era of Solar System
    formation and may have contributed water and organics to Earth, thereby
    providing a foundation for life. Primitive meteorites are among the
    least frequently sampled by falling to Earth and all samples received
    are biased by their ability to survive atmospheric passage. Direct
    investigation of both the fresh regolith and fresh lithospheric
    fragments is also impossible by any means other than sample return.
    Marco Polo will conduct a broad in situ analysis of the target and the
    geologic context for the samples prior to their acquisition. Sample
    return enables the power of the Earth's laboratories to identify major
    chronological events in solar system history, to search for pre-solar
    material yet unknown in meteorite samples, and to characterize in depth
    the nature of organic compounds that may be present. Thus, Marco Polo
    will provide extensive information for the characterization of NEOs. A
    participating scientist proposal has been submitted by a team of U.S.
    scientists to the ESA Cosmic Vision solicitation for this mission and
    we are in the preliminary stages of the process to award to this
    proposal.

    Q4b.  You also testified that ``The Canadians will be launching a
    spacecraft called NEOSSat. We have been discussing about how it can be
    utilized and making the data more available.'' Could you please
    describe the NEOSSat mission and how the data would benefit NASA's NEO
    search and/or characterization effort? What is the status of any
    discussions between NASA and the Canadian Space Agency on collaboration
    or access to data from this potential mission?

    A4b. The Canadian Space Agency (CSA) Near Earth Object Surveillance
    Satellite (NEOSSat) is a small satellite with a 0.15 meter aperture
    visible sensor which we understand will be launched sometime in 2009.
    The small aperture of the sensor means it will have little advantage
    over current ground based capabilities to detect and track NEOs.
    However, the continuous access offered by a space-based asset may
    provide some advantage to augment our capabilities, perhaps in the area
    of obtaining follow-up observations. NASA is in preliminary discussions
    with the CSA about collaboration or access to the data.

    Q5.  Dr. Tyson testified that the estimated the cost for a 12-year long
    survey would be $125 million. You testified that ``The LSST activity,
    of course, is one that needs to be resolved, in terms of whether they
    will have sufficient funding, and be able to put together the
    capability before we can begin to figure out how to work with them and
    leverage that system.'' Is NASA ruling-out partial support for
    development, even though such support could help ensure the
    availability of a system that could complete the expanded Survey at a
    considerably lower estimated cost than the options provided in NASA's
    report to Congress?

    A5. Maximizing use of the proposed LSST is probably part of the most
    cost-effective way for NASA to meet the 90 percent goal, though not on
    the timeline specified in the NASA Authorization Act of 2005 (P.L. 109-
    155). LSST (or a generic equivalent) is expected to be reprioritized by
    the National Academies in its upcoming astronomy and astrophysics
    decadal survey process, and this report will play a significant role in
    future prospects for LSST within the Foundation's broader set of
    priorities. NASA will continue to monitor its further development in
    order to insert at the appropriate time capabilities and commitments
    for its use in the NEO survey effort.

    Q6.  NASA Ames recently hosted a workshop on the potential of low-cost
    spacecraft to characterize NEOs. What, if any, plans does NASA have to
    pursue such missions?

    A6. NASA held a workshop on low-cost missions to NEOs at Ames Research
    Center on October 20-21, 2007. The workshop agenda blended three major
    themes: (1) the importance of characterizing small NEOs and the kinds
    of science measurements that need to be made; (2) how to get to the
    targets (i.e., target populations, orbital dynamics, direct vs.
    gravity-assist trajectories, opportunities for secondary payloads and
    missions of opportunity); and (3) options for low-cost missions (i.e.,
    small spacecraft, instruments, proximity operations, propulsion,
    landers, and impactors).
        A primary conclusion from the workshop is that low-cost missions to
    NEOs can play a role in exploring and characterizing these objects.
    Since a major objective is to explore the diversity of the NEO
    population and characterize their physical properties, launching
    multiple small missions could be cost-effective if the technology can
    be sufficiently matured. NASA already plans numerous ``mission of
    opportunity'' solicitations for which such proposals could be
    submitted.

    Questions submitted by Representative Tom Feeney

    Q1.  NASA's Near-Earth Object (NEO) report, delivered this March,
    provides several options for meeting the goal of achieving 90 percent
    detection, tracking and characterization of Potentially Hazardous
    Objects (PHOs), and the report establishes a clear relationship between
    resources invested and the time needed to achieve 90 percent coverage.
    In essence, the report shows that for an additional investment of
    approximately $536 million, we could buy-down a decade of time to
    complete the survey. In your view, is that additional investment
    necessary? Does the threat posed by PHOs compel faster completion of
    the survey?

    A1. NASA's analysis shows that not completing the NEO survey down to
    140 meters until the 2025-2030 timeframe does not statistically carry a
    level of risk that requires costly actions.

    Q2.  What are the most difficult types of NEOs to detect? Is there, for
    instance, a portion of the sky that won't be covered by ground-based
    facilities? Are there certain types of orbits that make it difficult to
    detect and track asteroids and comets?

    A2. Small NEOs composed of dark, carbonaceous materials are difficult
    to detect because they are intrinsically faint. NEOs of any size and
    composition on very Earth-like orbits can be potentially difficult to
    detect because they may spend a considerable number of years far from
    Earth on the other side of the Sun. Such objects may spend many years
    being effectively unobservable to ground- or Earth-based telescopes
    because of their apparent faintness or apparent proximity to the Sun.
        In general, the present bias toward NEO survey programs being
    located in the northern hemisphere does not significantly affect
    progress in completing the Spaceguard Survey for kilometer and larger
    NEOs; objects not detected during a southern-hemisphere-visible close
    approach will most likely be detected on a subsequent northern-
    hemisphere close pass. The present baseline survey plan for the Large
    Synoptic Survey Telescope (LSST) as developed by the project's
    proponents, which will, if funded, be based in the southern hemisphere
    and be a significant contributor to a follow-on survey for 140m and
    larger NEOs, conversely leaves some time gap in northern hemisphere NEO
    detection capabilities. The LSST project proponents are, however,
    actively exploring options for modifications to their baseline
    observing plan to include a portion of the northern ecliptic (the
    central plane of the solar system--where most NEOs spend most of their
    time) in order to increase their detection rate of NEOs.
        In any case, all surveys able to find 90 percent of potentially
    hazardous objects reduce the actuarial risk by the same amount, even if
    some small percentage of the objects is more difficult to detect by a
    specific system.

    Q3.  Once the LSST and Pan-STARRS telescopes are operating, and surveys
    for PHOs that are 140 meters or larger has commenced, what is the
    business and public safety case for expanding the search to detect and
    track smaller PHOs--or instance, down to a size of 50 meters? What are
    the cost and schedule implications?

    A3. An object of about 50 meters and average density would not be
    expected to survive all the way through the Earth's atmosphere and
    strike the surface, but this depends on the object's composition and
    structure. It could be expected to cause an explosion a few kilometers
    above the Earth's surface and may therefore cause some blast damage at
    ground level.
        The number of objects and frequency of impact increases as
    threshold size decreases, roughly based on the following figure, which
    is also Figure 2 in the report on NEO's NASA submitted to Congress in
    March 2007.

        Therefore, it is estimated that, while there may be about 20,000
    Potentially Hazardous Object (PHO)s 140 meters and larger, there are
    estimated to be about 100,000 PHOs 50 meters and larger and impacts by
    these smaller objects will therefore be more frequent.
        Simulations suggest that a next generation search for potentially
    hazardous objects (PHOs) down to 140 meters that includes only Pan-
    STARRS (assumed 2010 start) and LSST (assumed 2014 start) would
    discover roughly 42 percent of the PHOs larger than 50 meters by the
    end of 2020 and 59 percent by the end of 2029. Using a one-meter
    infrared telescope in a Venus-like orbit (assumed 2014 operations
    start) in addition to the ground-based Pan-STARRS and LSST surveys, the
    discovered population of 50 meters and larger sized objects would be
    complete to the level of 78 percent at the end of 2020 and 92 percent
    complete by the end of 2029. This assumed timeline would require that
    these systems operate for over a decade, and therefore might require
    multiple advanced spacecraft to be built (depending on design life),
    and would also require an even more capable operational data management
    infrastructure.
        Although no estimated costs for such a program are available, it is
    likely that such a search would require significantly more resources
    than necessary for the Congressional goal of 90 percent of 140 meters
    objects outlined in the NASA Authorization Act of 2005 (P.L. 109-155).
    The completion of the Congressional goal alone would retire 99 percent
    of the actuarial risk from PHOs of all sizes. Once significant progress
    has been made toward the Congressional goal, more consideration may be
    given to finding and tracking all potentially hazardous objects.

    Q4.  During the hearing several witnesses mentioned the Air Force's
    funding of the Pan-STARRS telescope facility in Hawaii as a possible
    new ground observatory that would be very adept at detecting NEOs. What
    is the status of Pan-STARRS and the likelihood that all four telescopes
    will be built? Would the Air Force be willing to make available a
    portion of the telescope's time to NEO surveys if less than four
    telescopes are built?

    A4. NASA understands that the Pan-STARRS Project Office acts as the Air
    Force's agent for discussion of capabilities related to NEO detection
    and survey, so all discussions have been directly with that project
    office at the University of Hawaii. Pan-STARRS currently is in check-
    out of its first prototype telescope at the Air Force facility on
    Haleakala, Maui. NASA cannot speculate on the future funding that will
    be made available by the Air Force to this project. However, the Pan-
    STARRS Project Office has already begun discussions with our NEO
    Program on how the single prototype telescope could be used to complete
    our currently ongoing one kilometer NEO survey, so it is likely they
    will work with the survey effort at whatever level of capability they
    are able to achieve.

    Q5.  How adaptable are current and proposed space-based infrared
    satellites to the role of NEO detection, tracking, and
    characterization? For instance, can Spitzer be used, even if its
    cryogenic coolant is depleted? And what about WISE (Wide-field Infrared
    Survey Explorer), due to be launched in 2009?

    A5. The majority of existing astronomical telescopes are designed with
    limited fields of view so they can focus on a specific object of
    interest. The fewer number of telescopes designed for survey work has
    relatively large fields of view (FOV) so that they can cover more sky
    more quickly. For instance, the Spitzer telescope's largest FOV is only
    five arc minutes by five arc minutes, or less than 10 percent of the
    area size that would be useful for a survey effort, usually considered
    to be at least one by one degree FOV. In ``back of the envelope''
    terms, this means it would take Spitzer more than ten times longer to
    conduct the survey effort than a telescope designed for it, even if it
    were dedicated to the effort full-time. This of course is not possible.
        Of greater potential is the Wide-field Infrared Survey Explorer
    (WISE) since, as its name implies, it has a wide FOV instrument.
    Currently being developed for a late 2009 launch for a six month
    astrophysics mission to map the infrared sky, the WISE instrument is
    also capable of detecting many asteroids, of which a portion will be
    NEOs. NASA is evaluating what it will take to make its operations
    useful to the NEO survey effort. However, the limitations of WISE
    relative to what it takes to do the NEO survey will limit the results
    NASA can get from it. Those limitations are its static pointing
    capability, because it only points along the plane of its orbit so a
    NEO must pass through that plane at some time to be detected by WISE,
    and its limited lifetime of only six months--although NASA is exploring
    what it would take to double that lifetime. If a spacecraft with the
    capability of WISE could operate for 10 years, it could go a long way
    towards completing the survey effort, but in only six months it may
    detect only about 400 previously unknown NEOs.
        The NASA study looked at all known spacecraft, including those
    operated and planned by the Air Force, and although several of these
    projects provided potential technology that could be used in a NEO
    survey spacecraft, no others had the right combination of capability
    and operational application that would be useful to the effort.

    Q6.  The NEO Survey Analysis indicates that a space-based observatory
    has certain advantages over ground-based telescopes. How seriously is
    NASA giving consideration to building and launching a space-based
    observatory?

    A6. The space-based alternatives have both benefits and risks when
    compared with ground-based assets. However, both types of systems can
    meet the Congressional goal of surveying 90 percent of 140 meters
    objects outlined in the NASA Authorization Act of 2005 (P.L. 109-155).
    If a system is built, the benefits and risks would be weighed against
    cost differences to make a selection. NASA does not have plans for
    building either a ground or space-based asset for NEO detection within
    its budgeted program. However, there are a few programmed space flight
    opportunities for competitive selection to which a capability might be
    proposed by the external community.

    Q7.  One deflection solution, suggested by NASA, is to detonate a
    nuclear device in the vicinity of a PHO. What are the advantages and
    disadvantages of using this approach? What circumstances would argue
    against using a nuclear device in lieu of alternative approaches?

    A7. The report on NEOs NASA submitted to the Congress in March 2007 did
    not recommend any one specific deflection solution--different scenarios
    might require completely different combinations of systems and
    solutions. However, the alternatives analysis for this report found:

              Deflection systems using nuclear explosives carry the
            highest deflection capability per kg of payload launched of the
            alternatives studied, therefore significantly reducing launch
            costs and increasing launch opportunities.

              Deflection systems using nuclear explosives were
            evaluated to be applicable to the widest range of threats
            (size, composition, shape, spin rate, etc.), although other
            alternatives may have advantages in certain scenarios.

              Nuclear explosives were evaluated to be among the
            most reliable and repeatable of the deflection techniques
            evaluated, with the highest level of technology readiness
            relative to alternatives.

              Impulsive methods, including nuclear explosives and
            kinetic impactors, provide their deflection instantaneously.
            This improves performance in ``quick response'' scenarios and
            permits multiple successive attempts that are likely to be
            necessary to achieve desired levels of deflection campaign
            reliability.

              Deflection systems using nuclear explosives are
            likely to be among the lowest cost due to significantly lower
            launch costs, lower payload development costs, and lower
            operations costs than slow push methods.

              Deflection systems using nuclear explosives carry
            unique operations and launch safety risks, all of which must be
            evaluated in the event a credible threat to the Earth is
            actually detected.

              Possible deflection scenarios cover a wide range of
            threat characteristics including size, mass, composition, spin
            rate, shape, cohesion, and number of gravitationally bound
            objects. As the NASA study indicated, the alternatives studied
            provide a ``tool kit'' of options to a decision-maker when an
            actual threat becomes apparent.

        Nuclear deflection is possibly the most effective option when cost,
    schedule, technology readiness, operational issues, and the need for
    characterization are considered, but it does have unique political,
    policy, and safety considerations. A series of one or more standoff
    nuclear devices may be the only option as the mass of the threat grows,
    but there are some instances (e.g., when the risk of fragmentation is
    high) where they may not be the primary selection.
        To achieve the level of reliability likely to be required to
    mitigate a potential threat, it is likely that multiple deflection
    techniques would need to be pursued as part of a deflection campaign
    such that no technology or system is a single point of failure. The use
    of nuclear explosives is evaluated to be very effective for many threat
    scenarios, and it is one of many options in the tool kit of defection
    alternatives.

    Questions submitted by Representative Dana Rohrabacher

    Q1.  The need for a comprehensive potentially hazardous Near-Earth
    Objects (NEO) program seems to require expertise of several agencies.
    How do you suggest coordination be handled?

    A1. At present, no department or agency of the United States is
    assigned the responsibility for a NEO contingency notification plan or
    the responsibility to mitigate threats posed by potentially hazardous
    near Earth asteroids and comets. As with other major natural disasters,
    a coordinated approach involving multiple federal agencies would
    clearly be required. NASA has not developed a position on how
    responsibilities should be assigned among U.S. departments and
    agencies.

    Q2.  Describe some of the proposed mitigation techniques and their
    trade offs.

    A2. The report on NEOs NASA submitted to the Congress in March 2007
    examined a number of techniques for deflecting a Potentially Hazardous
    Objects (PHO) that have been categorized as either ``impulsive'' or
    ``slow push.'' The tables below provide an overview of the impulsive
    methods and the slow push techniques, where the velocity change results
    from the continuous application of a small force, considered in the
    report. Each of these concepts is developed further in the report.

        In the impulsive category, the use of a nuclear device was found to
    be the most effective means to deflect a PHO. Because of the large
    amount of energy delivered, nuclear devices would require the least
    amount of detailed information about the threatening object, reducing
    the need for detailed characterization. While detonation of a nuclear
    device on or below the surface of a threatening object was found to be
    10-100 times more efficient than detonating a nuclear device above the
    surface, the standoff detonation would be less likely to fragment the
    target. A nuclear standoff mission could be designed knowing only the
    orbit and approximate mass of the threat, and missions could be carried
    out incrementally to reach the required amount of deflection.
    Additional information about the object's mass and physical properties
    would perhaps increase the effectiveness, but likely would not be
    required to accomplish the goal.
        Non-nuclear kinetic impact alternatives are the most effective non-
    nuclear option, transferring 10-100 times less momentum than nuclear
    options for a fixed launch mass. Impact velocities, varying from 10-50
    km/s, produced a factor-of-three variation in deflection performance.
    In addition, kinetic impacts are also sensitive to the porosity,
    elasticity, and composition of the target and may require large
    performance margins if these characteristics are not well determined.
        Slow push techniques analyzed in this study included a gravity
    tractor, which could alter the course of an object using the
    gravitational attraction of a massive spacecraft flying in close
    proximity, and a space tug, which could attach itself to a PHO and move
    it using high-efficiency propulsion systems. An attached space tug has
    generally 10-100 times more performance than the gravity tractor, but
    it requires more detailed characterization data and more robust
    guidance and control and surface attachment technologies. This
    technique could be effective in instances where small increments of
    velocity (less than one mm/s) could be applied to relatively small
    objects (less than 200 meters in diameter) over many decades. In
    general, the slow push systems were found to be at a very low
    technology readiness level (with the exception of the gravity tractor,
    which was medium) and would require significant development efforts.

    Q3.  What is your assessment of the need for a nuclear deflection
    capability?

    A3. There is no need for any deflection capability at this time. No
    impact threat has yet been identified. If a timely detection capability
    is fielded, there will most likely be significant warning time in which
    to develop other parts of the system such as sufficiently capable
    characterization and deflection spacecraft.

    Q4.  What are the weakest links in the ``system'' considering the
    overall goal to protect Earth from asteroid impacts?

    A4. Finding any potential threats so that their orbits can be
    determined is the weakest link by far. Unless we find threats, we will
    be unable to react. If we do find threats in a timely manner, there
    will very likely be significant warning time in which to develop other
    parts of the system such as sufficient characterization and deflection
    spacecraft.

    Q5.  Dr. Donald Yeomans stated that the highest priority regarding NEOs
    is to ``find them early, find them early, find them early.'' Yet NASA
    refused to recommend a program to find them (140 meters and larger)
    early as directed by law. Why? How does NASA justify this refusal?

    A5. NASA recommended an approach commensurate with the resources the
    Agency has been appropriated to accomplish its task.

    Q6.  What is your estimate on the number of undiscovered asteroids in
    the 140 meter and above range? Describe the potential damage that an
    asteroid in the 140 meter range could cause striking an ocean within,
    say, 500 miles from a U.S. coast.

    A6. The latest estimate of the total number of near-Earth asteroids
    (NEAs) larger than 140 meters in diameter is at least 20,000, but could
    be higher. However, the mean time between impacts of an object 140
    meters in size anywhere on the Earth's surface is estimated as about
    5,000 years; larger objects would be even less frequent. Objects
    striking the ocean within about 500 miles of a U.S. coast would be very
    infrequent, considerably longer than 100,000 years between events.
        The impact of a 140-meter-size object, striking at a typical impact
    speed of about 20 km/s, would deliver and explosive energy equivalent
    of some 170 megatons. Estimates of the tsunami effects from asteroid
    impact vary from researcher to researcher, but recent analyses, based
    on studies of waves generated by underwater explosions, indicate that
    the risk of impact tsunami from asteroid impacts in this size range has
    previously been overstated. Assuming precisely where an ocean impact
    might occur and then extrapolating potential damage from a related
    tsunami event lends to analysis of a ``worst on worst'' scenario that
    couples one highly improbable event to another and biases any resulting
    assessment. However, the recent studies have indicated the deepwater
    tsunami wave height at a point 1000 km (600 miles) from the impact of
    a 140-meter diameter stony asteroid might be on the order of only a few
    meters, but this deepwater wave height can increase dramatically when
    the waves reach the shoreline because the waves slow in shallow water
    and concentrate the wave energy. Based on recent assessments of tsunami
    risks for various locations, estimates are that the typical run-up
    factor (the ratio of the vertical height above sea level of the tsunami
    at its furthest point inland to its deepwater wave height) for impact
    tsunamis is only two to three, but this can vary considerably,
    depending on local topography and the direction of travel of the wave.
    All this suggests that one might expect a run up tsunami wave height of
    up to 10 meters or so from an ocean impact of a 140-meter diameter
    stony asteroid. This is roughly comparable to the measured run-ups from
    the tsunami that accompanied the Sumatra earthquake of December 26,
    2004.

    Q7.  Asteroids are more easily detected in the infrared spectrum. An
    asset such as the Wide-field Infrared Survey Explorer (WISE) satellite
    has an effective capability for searching for NEO's infrared output. Is
    WISE being tasked for this role? What other infrared detection devices
    can or will be used to detect NEOs?

    A7. WISE is not currently tasked for this role, but NASA is beginning
    to investigate what might be done with the WISE spacecraft that could
    be useful to the NEO survey effort. However, because of the limited
    duration of the WISE mission, its usefulness to the survey effort will
    be limited.
        NASA continues to look at other infrared capabilities in
    development or planning, but no other possibilities have yet been
    identified.
                       Answers to Post-Hearing Questions
    Responses by Scott Pace, Associate Administrator, Program Analysis and
            Evaluation, National Aeronautics and Space Administration
            (NASA)

    Questions submitted by Chairman Mark Udall

    Q1.  Dr. Green's testimony notes that ``The science community may
    propose a Near Earth Object (NEO) survey mission under the
    competitively-selected Discovery program.'' While some space science
    missions may offer the potential to contribute to NEO detection, in
    addition to their scientific investigations, a NEO survey mission is
    not a science mission if its purpose is primarily to detect NEOs. Does
    NASA have any plans to consider developing a dedicated Discovery-class
    space-based NEO survey mission to respond to the directive in the NASA
    Authorization Act of 2005? If so, how would NASA carry out such a
    development-what organization within NASA would have responsibility for
    it?

    A1. A great deal of science can be learned about the history and
    evolution of the Solar System by inventory of all the pieces of mass
    that exist in it, including those as small as a few 100 meter sized
    objects, and understanding how they evolved to their current positions.
    Exciting theories about the repositioning of the outer planets have
    recently come to light based on studies of the dynamics of the small
    body population.
        Although a small body survey mission has not yet be selected in the
    Discovery program, there have been a few missions proposed to
    accomplish this type of work. There are no plans to ``dedicate'' a
    Discovery mission to an NEO survey effort, but NASA solicitations will
    remain open to these types of proposals. If the selection process
    determines that such a mission is the best option, considering many
    technical feasibility factors in addition to the science, it will also
    be managed under the highly successful structure that has been
    instituted by NASA's Science Mission Directorate in the Planetary
    Science Division's Discovery Program.

    Q2.  NASA is planning to replace the existing Deep Space Network (DSN)
    antennas at Goldstone with an upgraded system. Will NASA maintain the
    current planetary radar capability at Goldstone as part of the upgrade?
    When, in concrete terms, will NASA know the specifics of plans for the
    DSN upgrade and planetary radar capability at Goldstone?

    A2. NASA is in the process of evaluating the driving requirements for
    capabilities provided by the DSN. These requirements, which include
    planetary radar capability at Goldstone, are being worked jointly among
    three Mission Directorates--Space Operations, Exploration Systems, and
    Science. This collaboration will drive the decision on the needed
    capabilities and will formulate the options for maintaining or
    upgrading the DSN assets. NASA expects to complete these plans by May
    2008.

    Q3.  NASA is providing funding to the Air Force's Pan-STARRS project.

    Q3a.  When did NASA start funding the project and how much funding is
    being provided on an annual basis? Is the funding provided through a
    grant, contract, or other type of agreement? How much funding does NASA
    plan to provide in total? Is the funding being provided to the Air
    Force or the University of Hawaii?

    A3a. The NASA NEO Program started limited funding to the Pan-STARRS
    project in 2007 with a partial award to a proposal submitted to the
    program by the University of Hawaii, who manages the Pan-STARRS
    development for the Air Force. This partial award was a one-year grant
    to the University of Hawaii of $450,000. Any future funding will depend
    on the success of pending and future proposals Pan-STARRS submits to
    competitive opportunities of the NEO Program that NASA announces
    through its annual Research Opportunities in Space and Earth Sciences.

    Q3b.  What, specifically, is the funding being used for and what will
    be provided to NASA in return?

    A3b. The funding is largely being used to adapt existing ``moving
    object detection'' software from a current Spaceguard project for use
    by the Pan-STARRS data processing system. This allows the option for
    NASA to make use of Pan-STARRS for NEO detection in the future.

    Q3c.  Who made the decision to fund Pan-STARRS--and did NASA approach
    the Air Force or did the Air Force approach NASA?

    A3c. The decision to fund a part of the proposal submitted by the
    University of Hawaii to the NEO Program was made through NASA's
    Research and Analysis peer review process. The final selecting official
    was Dr. James Green, Planetary Science Division Director.

    Q3d.  Has NASA discussed with the Air Force or University of Hawaii any
    changes to the observing times and sequences of Pan-STARRS to optimize
    the telescope for an expanded NEO search? If so, what is the status of
    those discussions?

    A3d. As Pan-STARRS nears operational capability, there have been
    preliminary discussions with the project office about what observing
    techniques and cadences could be used to best optimize the Pan-STARRS
    operations to achieve all its requirements, to include NEO detection.
    NASA has not had any direct discussions with the Air Force, as the
    Agency understands that the Pan-STARRS Project Office acts as its agent
    for these matters.

    Q4.  Dr. Green's testimony described NASA's NEO contingency
    notification plan, which lays out the procedures for notification up
    through the NASA Administrator if a NEO is detected with a significant
    probability of impacting Earth.

    Q4a.  Does a notification or warning system exist beyond NASA for
    informing the public and federal and State disaster and emergency
    response agencies? If not, what should be done?

    A4a. At present, no department or agency of the United States is
    assigned the responsibility for a contingency notification plan
    regarding threats posed by potentially hazardous near Earth asteroids
    and comets. As with other major natural disasters, a coordinated
    approach involving multiple federal agencies would clearly be required.
    NASA has not developed a position on how responsibilities should be
    assigned among U.S. departments and agencies.

    Q4b.  How will policy and legal issues involved in addressing NEOs--
    e.g., when and how to warn the public and whether to use nuclear
    explosives to deflect an asteroid--be handled on national and
    international levels? What steps have NASA and other federal agencies
    taken to date to address such issues?

    A4b. At present, no department or agency of the United States is
    assigned the responsibility to mitigate threats posed by potentially
    hazardous near Earth asteroids and comets. As with other major natural
    disasters, a coordinated approach involving multiple federal agencies
    would clearly be required. NASA has not developed a position on both
    the policy and legal issues addressing NEOs or how responsibilities
    should be assigned among U.S. departments and agencies. NASA would
    defer to the Department of State to assess the best approaches to
    international cooperation on this issue.

    Questions submitted by Representative Tom Feeney

    Q1.  Once the LSST and Pan-STARRS telescopes are operating, and surveys
    for potentially hazardous objects (PHOs) that are 140 meters or larger
    has commenced, what is the business and public safety case for
    expanding the search to detect and track smaller PHOs--for instance,
    down to a size of 50 meters? What are the cost and schedule
    implications?

    A1. An object of about 50 meters and average density would not be
    expected to survive all the way through the Earth's atmosphere and
    strike the surface, but this depends on the object's composition and
    structure. It could be expected to cause an explosion a few kilometers
    above the Earth's surface and may therefore cause some blast damage at
    ground level.
        The number of objects and frequency of impact increases as
    threshold size decreases, roughly based on the following figure, which
    is also Figure 2 in the report on NEO's NASA submitted to Congress in
    March 2007.

        Therefore, it is estimated that, while there may be about 20,000
    PHOs 140 meters and larger, there are estimated to be about 100,000
    PHOs 50 meters and larger and impacts by these smaller objects will
    therefore be more frequent.
        Simulations suggest that a next generation search for potentially
    hazardous objects (PHOs) down to 140 meters that includes only Pan-
    STARRS (assumed 2010 start) and LSST (assumed 2014 start) would
    discover roughly 42 percent of the PHOs larger than 50 meters by the
    end of 2020 and 59 percent by the end of 2029. Using a one-meter
    infrared telescope in a Venus-like orbit (assumed 2014 operations
    start) in addition to the ground-based Pan-STARRS and LSST surveys, the
    discovered population of 50 meters and larger sized objects would be
    complete to the level of 78 percent at the end of 2020 and 92 percent
    complete by the end of 2029. This assumed timeline would require that
    these systems operate for over a decade, and therefore might require
    multiple advanced spacecraft to be built (depending on design life),
    and would also require an even more capable operational data management
    infrastructure.
        Although no estimated costs for such a program are available, it is
    likely that such a search would require significantly more resources
    than necessary for the Congressional goal of 90 percent of 140 meters
    objects outlined in the NASA Authorization Act of 2005 (P.L. 109-155).
    The completion of the Congressional goal alone would retire 99 percent
    of the actuarial risk from PHOs of all sizes. Once significant progress
    has been made toward the Congressional goal, more consideration may be
    given to finding and tracking all potentially hazardous objects.

    Q2.  How adaptable are current and proposed space-based infrared
    satellites to the role of NEO detection, tracking, and
    characterization? For instance, can Spitzer be used, even if its
    cryogenic coolant is depleted? And what about WISE (Wide-Field Infrared
    Survey Explorer), due to be launched in 2009?

    A2. The majority of existing astronomical telescopes are designed with
    limited fields of view so they can focus on a specific object of
    interest. The fewer number of telescopes designed for survey work has
    relatively large fields of view (FOV) so that they can cover more sky
    more quickly. For instance, the Spitzer telescope's largest FOV is only
    five arc minutes by five arc minutes, or less than 10 percent of the
    area size that would be useful for a survey effort, usually considered
    to be at least one by one degree FOV. In ``back of the envelope''
    terms, this means it would take Spitzer more than ten times longer to
    conduct the survey effort than a telescope designed for it, even if it
    were dedicated to the effort full-time. This of course is not possible.
        Of greater potential is the Wide-field Infrared Survey Explorer
    (WISE) since, as its name implies, it has a wide FOV instrument.
    Currently being developed for a late 2009 launch for a six month
    astrophysics mission to map the infrared sky, the WISE instrument is
    also capable of detecting many asteroids, of which a portion will be
    NEOs. NASA is evaluating what it will take to make its operations
    useful to the NEO survey effort. However, the limitations of WISE
    relative to what it takes to do the NEO survey will limit the results
    NASA can get from it. Those limitations are its static pointing
    capability, because it only points along the plane of its orbit so a
    NEO must pass through that plane at some time to be detected by WISE,
    and its limited lifetime of only six months--although NASA is exploring
    what it would take to double that lifetime. If a spacecraft with the
    capability of WISE could operate for 10 years, it could go a long way
    towards completing the survey effort, but in only six months it may
    detect only about 400 previously unknown NEOs.
        The NASA study looked at all known spacecraft, including those
    operated and planned by the Air Force, and although several of these
    projects provided potential technology that could be used in a NEO
    survey spacecraft, no others had the right combination of capability
    and operational application that would be useful to the effort.

    Q3.  The NEO Survey Analysis indicates that a space-based observatory
    has certain advantages over ground-based telescopes. How seriously is
    NASA giving consideration to building and launching a space-based
    observatory?

    A3. The space-based alternatives have both benefits and risks when
    compared with ground-based assets. However, both types of systems can
    meet the Congressional goal of surveying 90 percent of 140 meters
    objects outlined in the NASA Authorization Act of 2005 (P.L. 109-155).
    If a system is built, the benefits and risks would be weighed against
    cost differences to make a selection. NASA does not have plans for
    building either a ground or space-based asset for NEO detection within
    its budgeted program. However, there are a few programmed space flight
    opportunities for competitive selection to which a capability might be
    proposed by the external community.

    Q4.  One deflection solution, suggested by NASA, is to detonate a
    nuclear device in the vicinity of a PHO. What are the advantages and
    disadvantages of using this approach? What circumstances would argue
    against using a nuclear device in lieu of alternative approaches?

    A4. The report on NEOs NASA submitted to the Congress in March 2007 did
    not recommend any one specific deflection solution--different scenarios
    might require completely different combinations of systems and
    solutions. However, the alternatives analysis for this report found:

              Deflection systems using nuclear explosives carry the
            highest deflection capability per kg of payload launched of the
            alternatives studied, therefore significantly reducing launch
            costs and increasing launch opportunities.

              Deflection systems using nuclear explosives were
            evaluated to be applicable to the widest range of threats
            (size, composition, shape, spin rate, etc.), although other
            alternatives may have advantages in certain scenarios.

              Nuclear explosives were evaluated to be among the
            most reliable and repeatable of the deflection techniques
            evaluated, with the highest level of technology readiness
            relative to alternatives.

              Impulsive methods, including nuclear explosives and
            kinetic impactors, provide their deflection instantaneously.
            This improves performance in ``quick response'' scenarios and
            permits multiple successive attempts that are likely to be
            necessary to achieve desired levels of deflection campaign
            reliability.

              Deflection systems using nuclear explosives are
            likely to be among the lowest cost due to significantly lower
            launch costs, lower payload development costs, and lower
            operations costs than slow push methods.

              Deflection systems using nuclear explosives carry
            unique operations and launch safety risks, all of which must be
            evaluated in the event a credible threat to the Earth is
            actually detected.

              Possible deflection scenarios cover a wide range of
            threat characteristics including size, mass, composition, spin
            rate, shape, cohesion, and number of gravitationally bound
            objects. As the NASA study indicated, the alternatives studied
            provide a ``tool kit'' of options to a decision-maker when an
            actual threat becomes apparent.

        Nuclear deflection is possibly the most effective option when cost,
    schedule, technology readiness, operational issues, and the need for
    characterization are considered, but it does have unique political,
    policy, and safety considerations. A series of one or more standoff
    nuclear devices may be the only option as the mass of the threat grows,
    but there are some instances (e.g., when the risk of fragmentation is
    high) where they may not be the primary selection.
        To achieve the level of reliability likely to be required to
    mitigate a potential threat, it is likely that multiple deflection
    techniques would need to be pursued as part of a deflection campaign
    such that no technology or system is a single point of failure. The use
    of nuclear explosives is evaluated to be very effective for many threat
    scenarios, and it is one of many options in the tool kit of defection
    alternatives.

    Questions submitted by Representative Dana Rohrabacher

    Q1.  The need for a comprehensive potentially hazardous Near-Earth
    Objects (NEO) program seems to require expertise of several agencies.
    How do you suggest coordination be handled?

    A1. At present, no department or agency of the United States is
    assigned the responsibility for a NEO contingency notification plan or
    the responsibility to mitigate threats posed by potentially hazardous
    near Earth asteroids and comets. As with other major natural disasters,
    a coordinated approach involving multiple federal agencies would
    clearly be required. NASA has not developed a position on how
    responsibilities should be assigned among U.S. departments and
    agencies.

    Q2.  Describe some of the proposed mitigation techniques and their
    trade offs.

    A2. The report on NEOs NASA submitted to the Congress in March 2007
    examined a number of techniques for deflecting a PHO that have been
    categorized as either ``impulsive'' or ``slow push.'' The tables below
    provide an overview of the impulsive methods and the slow push
    techniques, where the velocity change results from the continuous
    application of a small force, considered in the report. Each of these
    concepts is developed further in the report.

        In the impulsive category, the use of a nuclear device was found to
    be the most effective means to deflect a PHO. Because of the large
    amount of energy delivered, nuclear devices would require the least
    amount of detailed information about the threatening object, reducing
    the need for detailed characterization. While detonation of a nuclear
    device on or below the surface of a threatening object was found to be
    10-100 times more efficient than detonating a nuclear device above the
    surface, the standoff detonation would be less likely to fragment the
    target. A nuclear standoff mission could be designed knowing only the
    orbit and approximate mass of the threat, and missions could be carried
    out incrementally to reach the required amount of deflection.
    Additional information about the object's mass and physical properties
    would perhaps increase the effectiveness, but likely would not be
    required to accomplish the goal.
        Non-nuclear kinetic impact alternatives are the most effective non-
    nuclear option, transferring 10-100 times less momentum than nuclear
    options for a fixed launch mass. Impact velocities, varying from 10-50
    km/s, produced a factor-of-three variation in deflection performance.
    In addition, kinetic impacts are also sensitive to the porosity,
    elasticity, and composition of the target and may require large
    performance margins if these characteristics are not well determined.
        Slow push techniques analyzed in this study included a gravity
    tractor, which could alter the course of an object using the
    gravitational attraction of a massive spacecraft flying in close
    proximity, and a space tug, which could attach itself to a PHO and move
    it using high-efficiency propulsion systems. An attached space tug has
    generally 10-100 times more performance than the gravity tractor, but
    it requires more detailed characterization data and more robust
    guidance and control and surface attachment technologies. This
    technique could be effective in instances where small increments of
    velocity (less than one mm/s) could be applied to relatively small
    objects (less than 200 meters in diameter) over many decades. In
    general, the slow push systems were found to be at a very low
    technology readiness level (with the exception of the gravity tractor,
    which was medium) and would require significant development efforts.

    Q3.  What is your assessment of the need for a nuclear deflection
    capability?

    A3. There is no need for any deflection capability at this time. No
    impact threat has yet been identified. If a timely detection capability
    is fielded, there will most likely be significant warning time in which
    to develop other parts of the system such as sufficiently capable
    characterization and deflection spacecraft.

    Q4.  What are the weakest links in the ``system'' considering the
    overall goal to protect Earth from asteroid impacts?

    A4. Finding any potential threats so that their orbits can be
    determined is the weakest link by far. Unless we find threats, we will
    be unable to react. If we do find threats in a timely manner, there
    will very likely be significant warning time in which to develop other
    parts of the system such as sufficient characterization and deflection
    spacecraft

    Q5.  Dr. Donald Yeomans stated that the highest priority regarding NEOs
    is to ``find them early, find them early, find them early.'' Yet NASA
    refused to recommend a program to find them (140 meters and larger)
    early as directed by law. Why? How does NASA justify this refusal?

    A5. NASA recommended an approach commensurate with the resources the
    Agency has been appropriated to accomplish its tasks.
                       Answers to Post-Hearing Questions
    Responses by Donald K. Yeomans, Manager, Near-Earth Object Program
            Office, Jet Propulsion Laboratory

    Questions submitted by Chairman Mark Udall

    Q1.  Planetary radar facilities have been cited as critical for
    providing more precise orbital determinations of potentially hazardous
    NEOs. However, the two radar facilities currently being used to obtain
    data on NEOs [Arecibo and Goldstone] may not be available in the
    future. What are the implications should existing planetary radar
    facilities become unavailable?

    A1. While the two mentioned planetary radars cannot participate in the
    near-Earth object (NEO) discovery process, they do provide very
    accurate range and velocity information that is not available with the
    traditional optical positional data used to discover these objects.
    Together with optical observations, the use of radar data within the
    NEO orbit determination process immediately refines the object's orbit
    and allows the NEO's future motion to be accurately determined so that
    future close Earth approach distances can be ascertained far earlier
    than would be the case without the radar data. After several years of
    optical data taken at multiple returns of the NEO to the Earth's
    neighborhood, a NEO orbit computed based solely upon the optical data
    can also accurately predict the object's future motion. However, it
    often takes many years before the necessary optical data are in hand
    and for the more numerous smaller NEOs, the first discovery opportunity
    is often the best opportunity to gather the necessary data prior to a
    potentially threatening pass near the Earth. In short, radar data are
    most critical for quickly identifying the most threatening objects and
    should one be found on an Earth threatening trajectory, the use of
    radar data could make the difference between having the time to
    mitigate the threat or not.

    Q2.  Could you please explain how the Arecibo and Goldstone planetary
    radar facilities work together? How, if at all, would the loss of one
    of the facilities affect the orbital determination of a potentially
    hazardous object? Would there be a potential effect on the accuracy,
    the time required for determining a trajectory, the number of objects
    to be tracked, or some combination of these factors?

    A2. As noted in the response to Question 1, the use of radar data
    allows for a rapid identification of a potentially hazardous object
    (PHO) and a potentially Earth threatening future encounter. Although
    the two planetary radars cannot ``see'' every PHO at every return to
    the Earth's neighborhood, the loss of one of the planetary radars would
    substantially decrease the number of PHOs having the radar data
    necessary to quickly secure their orbits. Hence, without these radar
    observations, it would take several years more of the optical data to
    secure their orbits to a point where an Earth threatening encounter
    could be ruled out (or in). With the use of radar data in the PHO orbit
    determination process, there would be far more time to deal with the
    PHO if it turned out to be on an Earth threatening trajectory. The
    Arecibo and Goldstone radar facilities are very complementary in that
    the 70 meter sized Goldstone antenna is movable and can track objects
    within its range from horizon to horizon (8-10 hours). The 305 meter
    Arecibo antenna has nearly three times the reach, or range, of the
    Goldstone antenna but can only track objects for about two hours within
    20 degrees of its overhead (zenith) position. Often a PHO is first
    tracked by Arecibo and then by Goldstone (or vice versa) so the use of
    both instruments is particularly valuable in terms of providing the
    extended observations necessary to characterize the PHO's size, shape,
    density, spin state and whether or not it has a moon. Knowledge of
    these latter characteristics will be invaluable for science and for
    selecting an appropriate mitigation technology--should that become
    necessary.

    Q3.  The asteroid Apophis has been identified as an object that has a
    small chance of impacting Earth in 2036. What role will Arecibo and/or
    Goldstone play in improving our understanding of Apophis and refining
    predictions of a potential impact?

    A3. Potentially hazardous asteroid Apophis will make a very close
    approach to Earth on April 13, 2029 coming as near as 4.6 Earth radii
    from the Earth's surface (i.e., lower than communication satellites in
    geosynchronous orbits about Earth). With the aid of radar data taken in
    2005 and 2006, the orbit of Apophis has been accurately determined and
    an Earth collision in 2029 ruled out. However, in the unlikely event
    that Apophis passes within a 600 meter sized ``keyhole'' in space
    during the 2029 close Earth passage, Apophis will return seven years
    later and strike the Earth (April 13, 2036). To further refine the
    existing orbit for Apophis and rule out a passage through this tiny
    keyhole, we will need to understand and model some very subtle
    perturbative effects due to the pressure of sunlight and the radiation
    of heat from the surface of Apophis. In order to do this, it will be
    important to determine the size, shape and spin state of Apophis.
    Arecibo radar observations made in early 2013 would allow these
    physical observations to be made. Together with optical data, radar
    observations in 2013 would reduce the 2029 orbit uncertainties by more
    than 90 percent. Thus, it is very likely that the passage of Apophis
    through the 2029 keyhole (and impact in 2036) can be ruled out.

    Q4.  How do the capabilities of Pan-STARRS compare to that of LSST? Are
    they complementary facilities for an expanded NEO Survey, or could one
    facility meet the goal of detecting NEOs as small as 140 meters in size
    in a timely fashion?

    A4. Both Pan-STARRS and LSST have the capability to be far more
    efficient in finding NEOs than any of the currently operating surveys.
    The efficiency with which a search telescope can detect NEOs is
    proportional to the size of the telescope's aperture area multiplied by
    the telescope's field of view. The four telescope array of the planned
    Pan-STARRS has four 1.8 meter telescopes each with a field of view of
    seven square degrees. LSST has a single 8.4 meter telescope (effective
    aperture = 6.7 meters) with a 9.6 square degree field so LSST would be
    about five times more efficient in terms of NEO discoveries. However,
    Pan-STARRS will be located on Hawaii in the northern hemisphere while
    LSST will be located in the southern hemisphere so these telescopes
    will be viewing different regions of the sky and will have different
    weather patterns. Thus they will be very complementary search systems
    and their observing schedules, search regions and data reduction
    techniques could be coordinated to ensure a more efficient and robust
    search strategy. With a start in 2014, the LSST, optimized for NEO
    searches (as described in Dr. Tyson's testimony), could reach the goal
    of discovering 90 percent of the potentially hazardous asteroids 140
    meters and larger by 2026. In addition, with the Pan-STARRS four
    telescope array also operational by 2010, the goal could be reached
    almost two years earlier. Furthermore, the placement of Pan-STARRS in
    the north and LSST in the south would provide for an increase in
    warning efficiency for those smaller and more numerous objects that are
    discovered on their final approach to Earth.

    Q5.  The Discovery Channel Telescope is under construction and expected
    to become operational in 2010. The telescope design is expected to
    enable versatility in its use, which could include the detection of
    near-Earth asteroids. One estimate puts the total cost of building the
    telescope at $40-50 million. What contribution, if any, would this type
    of low-cost telescope provide to the expanded NEO Survey? Should this
    system be considered as part of the next-generation search or as part
    of a gap-filler until a Survey using LSST and/or Pan-STARRS gets
    underway?

    A5. The Discovery Channel Telescope has an aperture size of 4.2 meters
    and when used in the (as yet unfunded) prime focus mode, will have a
    field of view of 2.3 square degrees. For NEO discovery, it will then be
    about two times less efficient than Pan-STARRS and 11 times less
    efficient that LSST. However, the Discovery Channel Telescope will be
    far superior to any currently used NEO search telescopes and could by
    itself discover more than 50 percent of the PHAs larger than 140 meters
    within ten years time. It will be located in Arizona so that it will be
    in a different region of the world (with different weather patterns)
    from both Pan-STARRS and LSST. The Discovery Channel Telescope should
    indeed be considered part of the next generation search.

    Q6.  What are the data management requirements to support the expanded
    Survey and what should the priorities be in addressing those
    requirements? How big a job is it likely to be?

    Q6a.  Dr. Green's testimony indicates that NASA has started to evaluate
    the needs of the Minor Planet Center to accommodate the increase in
    detection that will result in an expanded survey. Should NASA consider
    other entities for handling data management under the expanded search?
    Should the data management task be competed?

    A6a. Currently the Minor Planet Center (MPC) is receiving, processing
    and archiving up to 75,000 observations each day and as the next
    generation of search gets underway, that amount could increase 100-
    fold. Steps are already underway to establish the interfaces necessary
    for the MPC to interact with the next generation surveys and manage the
    enormous increase in data they will provide. In a change from the
    current survey data processing procedures, the next generation surveys
    (e.g., Pan-STARRS, LSST) will do much of their own data processing,
    including the identification of their nightly observations with
    existing asteroids, the computation of preliminary orbits for newly
    discovered objects and the archiving of these data. This moving object
    pipeline system (MOPS) is well along in its development and both Pan-
    STARRS and LSST will take advantage of it. Hence, while the increased
    work load on the MPC will be significant, much of the work will be
    carried out by the surveys themselves. Steps are being taken to ensure
    that the transition to the next generation search is smooth and that
    the data processing is nearly completely autonomous so only a modest
    increase in staffing at the MPC will be required. In the NASA call for
    Near-Earth Object Observations peer-reviewed proposals in early 2008,
    there will be an opportunity for other institutions to compete for the
    role that the MPC in Cambridge Massachusetts is currently fulfilling.

    Q7.  How much time would be required to prepare a mitigation approach
    if a hazardous object were discovered to be on a collision course with
    Earth? How much time would likely be available?

    A7. Once the current NEO survey goal has been reached, some 90 percent
    of the one kilometer and larger sized NEOs will have been discovered.
    Once the next generation search is complete, all of the one kilometer-
    sized NEOs will have been discovered along with 90 percent of those
    potentially hazardous objects larger than 140 meters. At that point, 99
    percent of the statistical or actuarial risk from NEOs will have been
    retired since it will then be possible to track their motions decades
    into the future and determine if any among them represent a threat to
    Earth. This is the key issue for getting on with the next generation
    search--we must find them early enough to allow the time to mitigate if
    a true Earth threatening object is discovered. After the next
    generation of search is complete, 90 percent of the 140 meter sized
    objects will have well understood future motions and should one of them
    have a significant non-zero Earth impact probability, there would be
    typically decades to further refine the orbit using optical and radar
    data and in the vast majority of cases, these additional data will
    collapse the orbital uncertainties to such an extent that troublesome
    future Earth encounters can be ruled out. If, in the unlikely event
    that an Earth impact cannot be ruled out, there should be the necessary
    number of years to place a spacecraft in orbit about the asteroid,
    track it and hence accurately monitor the asteroid's motion to
    determine if the threat remains real. In addition, this rendezvous
    spacecraft would then be available to monitor the asteroid's motion
    subsequent to a deflection attempt (e.g., by an impacting spacecraft)
    to verify that the attempt had been successful in avoiding the
    potential Earth impact at the predicted time. This monitor spacecraft
    could also verify that the deflection attempt did not push the asteroid
    into a tiny nearby keyhole in space that would bring it back to a
    subsequent Earth impact. This latter possibility, while very unlikely,
    could then be mitigated using the small gravitational ``pull'' of the
    close neighboring spacecraft being used as a gravity tractor.
        The development and flight of a rendezvous spacecraft along with
    the mitigation approach would likely take 10-20 years depending upon
    the impactor's orbit, the available launch vehicle, the launch
    opportunities and the mitigation technique itself. The next generation
    of search is designed to provide many decades of advance warning time
    for the vast majority of Earth threatening asteroids.

    Q8.  Dr. Green's testimony described NASA's NEO contingency
    notification plan, which lays out the procedures for notification up
    through the NASA Administrator if a NEO is detected with a significant
    probability of impacting Earth. Does a notification or warning system
    exist beyond NASA for informing the public and federal and State
    disaster and emergency response agencies? If not, what should be done?

    A8. To my knowledge, there currently exists no notification or warning
    system beyond NASA for informing the public and federal/State disaster
    and emergency response agencies. However, the next generation of search
    for potentially hazardous objects (PHOs) will dramatically increase
    both the number of known PHOs in the population and the number of
    warnings where the risk of a PHO Earth impact cannot be immediately
    ruled out. During the next generation of PHO search, these warnings
    could increase by up to a factor of 40 over what we currently
    experience. I would recommend that the lines of communication be opened
    between NASA's NEO program and the U.S. disaster response agencies to
    begin the long-term planning for these warnings and for the rare
    circumstance where one of these PHO warnings turns into a real threat.

    Questions for the Record Submitted by Representative Tom Feeney

    Q1.  NASA's NEO report, delivered this March, provides several options
    for meeting the goal of achieving 90 percent detection, tracking and
    characterization of Potentially Hazardous Objects, and the report
    establishes a clear relationship between resources invested and the
    time needed to achieve 90 percent coverage. In essence, the report
    shows that for an additional investment of approximately $536 million,
    we could buy-down a decade of time to complete the survey. In your
    view, is that additional investment necessary? Does the threat posed by
    PHOs compel faster completion of the survey?

    A1. While the mean time between impacts for 140 meter sized potentially
    hazardous objects (PHOs) is approximately 5,000 years, the next impact
    is equally likely to occur tomorrow morning or in 5,000 years. The mean
    time between impacts of the far more numerous 50 meter sized PHOs is
    about 700 years and hence the impact probability for one of these
    impacts in this century is about 13 percent. NASA currently invests
    approximately $4 million dollars per year in its NEO Observations
    program and if the current NEO surveys continue at the current level of
    activity, it would take more than a century to reach the goal of
    finding 90 percent of the PHOs larger than 140 meters. To reach this
    goal by the end of the 2020, as requested in the NASA Authorization Act
    of 2005, the survey could be done with the aid of a dedicated LSST
    class 8.4 meter telescope (2015 start time) or done using a space-based
    infrared telescope of 0.5 or 1.0 meters (2012-2014 start). If the 2020
    goal line is relaxed a few years, the 90 percent completion goal could
    be achieved in 2026 with the LSST used in a shared mode with only 15
    percent of the time being devoted exclusively to PHO searches. As
    outlined in the testimony of Dr. Tyson, this option would require about
    $125 million dollars for the entire effort through 2026.
        The threat posed by PHOs is real and the impact of a 140 meter
    sized PHO would strike the Earth's surface with the energy equivalent
    of about 100 mega tons of TNT explosives--roughly 7,700 times more
    energetic than the Hiroshima nuclear device. Nevertheless, it is my
    personal opinion that, given the infrequency of impacts by relatively
    large PHOs upon the Earth, there is no compelling reason to insist upon
    a survey completion by 2020; a relaxation of the completion date by 5-
    10 years would be acceptable.

    Q2.  What are the most difficult types of NEOs to detect? Is there, for
    instance, a portion of the sky that won't be covered by ground-based
    facilities? Are there certain types of orbits that make it difficult to
    detect and track asteroids and comets?

    A2. With the exception of a single search telescope located in Siding
    Spring Australia, all current NASA supported NEO search telescopes are
    located in the northern hemisphere. However, the orbits of NEOs will,
    over time, bring them into view from the northern hemisphere so that
    for discovery purposes, the paucity of search telescopes in the south
    is not a particular problem. However, for warning of objects that are
    on a final Earth threatening trajectory, northern and southern
    hemisphere observation capabilities are required. The most difficult
    NEOs to detect include those objects that 1.) spend most of their time
    interior to the Earth's orbit (i.e., they are rarely visible in a dark
    sky) or 2.) they do not often return to the Earth's neighborhood. This
    latter scenario can arise because they have relatively long orbital
    periods about the sun or their orbital periods are similar to that of
    the Earth so they can spend long periods of time before approaching the
    Earth or becoming visible in the night sky.

    Q3.  Once the LSST and Pan-STARRS telescopes are operating, and surveys
    for PHOs that are 140 meters or larger has commenced, what is the
    business and public safety case for expanding the search to detect and
    track smaller PHOs--for instance, down to a size of 50 meters? What are
    the cost and schedule implications?

    A3. Fifty meters is roughly the lower size limit where a rocky Earth
    impacting object could be expected to cause ground damage from an air
    blast. That is, an object of this size would not generally punch
    through the Earth's atmosphere and strike the Earth but it would be
    expected to cause an explosion a few kilometers above the Earth's
    surface and hence cause ground damage. For example, nearly 100 years
    ago in June 1908, a 50 meter sized object is thought to have created a
    5-10 megaton (of TNT) explosive event in the Tunguska region of Siberia
    causing ground damage over a region of 2,000 square kilometers.
        As one moves down to smaller and smaller PHOs, they become more and
    more numerous so while there may be more than 10,000 PHOs larger than
    140 meters, there is likely to be seven times that number of PHOs
    larger than 50 meters. The current ongoing survey goal to discover and
    track 90 percent of the one kilometer and larger sized objects has
    discovered about five percent of the smaller objects down to 140 meters
    in size. Similarly, simulations suggest that the next generation search
    for PHOs down to 140 meters that includes only Pan-STARRS (2010 start)
    and LSST (2014 start) will discover roughly 42 percent of the
    potentially hazardous objects (PHOs) larger than 50 meters by the end
    of 2020 and 59 percent by the end of 2029. If one were to include in
    the next generation search a one meter infrared telescope in a Venus-
    like orbit (2014 start) in addition to the ground-based Pan-STARRS and
    LSST surveys, the discovered population of 50 meter and larger sized
    objects would be complete to the level of 78 percent at the end of 2020
    and 92 percent complete by the end of 2029. However, this latter result
    would depend upon a rather long 15 year lifetime for the infrared space
    telescope and would entail significant data down-link issues.
        I am not aware of a study to determine survey costs for discovering
    and tracking 90 percent of the 50 meter sized PHOs but it would likely
    require far more resources than have been considered to date. It is
    true that the likelihood of Earth being struck with a 50 meter sized
    PHO is about seven times that for a PHO of 140 meters. However, at some
    point there is a crossing between the diminishing hazard from smaller
    and smaller objects and the increasing costs required to find them. It
    should be noted that the completion of the goal to discover and track
    90 percent of the PHOs larger than 140 meters would retire 99 percent
    of the actuarial risk from PHOs of all sizes so this is the appropriate
    goal for the next generation of search. A future study of this issue
    would have to determine whether or not a comprehensive survey to
    discover 90 percent of the smaller PHOs down to 50 meters in the near
    future would be cost effective.

    Q4.  During the hearing several witnesses mentioned the Air Force's
    funding of the Pan-STARRS telescope facility in Hawaii as a possible
    new ground observatory that would be very adept at detecting NEOs. What
    is the status of Pan-STARRS and the likelihood that all four telescopes
    will be built? Would the Air Force be willing to make available a
    portion of the telescope's time to NEO surveys if less than four
    telescopes are built?

    A4. The Pan-STARRS project is a University of Hawaii Institute for
    Astronomy effort that has been sponsored through United States Air
    Force grants beginning in FY 2002. The project has been proceeding well
    in developing the world's largest digital cameras, high precision wide
    field optics, and software systems to process and archive an
    unprecedented stream of world class astronomical research data. The
    ownership and operations of the Pan-STARRS systems is under the
    authority of the University of Hawaii.
        The ultimate goal is to construct four co-located 1.8 meter
    aperture telescopes (PS4) that will function as a single unit each
    clear night to search the entire accessible sky twice each lunar month
    (about 28 days). It seems likely that the PS4 four telescope system
    will be built within a few years, but the precise schedule will depend
    upon the availability and timing of the necessary funding as well as
    completing the construction permitting process that includes a federal
    environmental impact statement (EIS). As noted in the EIS Preparation
    Notice published in the Federal Register in January 2007, the preferred
    site is at the Mauna Kea summit on the Big Island of Hawaii, and the
    alternate site is the Haleakala summit on the island of Maui.
        Prior to construction of the four telescope array, a prototype
    single 1.8 meter telescope (PS1) has been built and sited at the
    Haleakala summit. The state-of-the-art 1400 megapixel (1.4 billion
    pixel) CCD camera has been built, tested and mated to the telescope,
    and the telescope itself achieved ``first light'' on Aug. 22, 2006.
    Development is nearly complete of the image processing pipeline (IPP)
    and the Moving Object Processing System (MOPS) that is designed to
    identify moving objects within our Solar System (mostly asteroids), and
    preliminary testing is well underway. An international consortium has
    committed $10M to fund a 3.5 year PS1 science mission that should begin
    in mid-2008. Once operational, the primary objective of PS1 is to
    discover near-Earth objects and it should be more than 20 times more
    efficient at finding them than any currently operational NEO search
    effort. This will be true even though the telescope will be conducting
    a suite of other scientific observations including studies of outer
    solar system objects, planets around other stars, supernova, galaxy
    clusters, and gravitational lensing. The supernova and gravitational
    lensing studies will significantly clarify our current understanding of
    the dark energy and dark matter issues at the forefront of modern
    cosmology.
        At this time, the best estimate for beginning PS4 construction is
    late 2009 or early 2010. This is primarily due to the timescale for
    completing the EIS and obtaining the necessary construction approvals.
    If sufficient funding continues to be available, the likelihood is high
    to successfully complete the full system. Commissioning of the first
    one or two PS4 telescopes should begin in 2011 with the completed four
    telescope suite becoming fully operational in 2013.

    Q5.  One deflection solution, suggested by NASA, is to detonate a
    nuclear device in the vicinity of a PHO. What are the advantages and
    disadvantages of using this approach? What circumstances would argue
    against using a nuclear device in lieu of alternative approaches?

    A5. There are two categories of mitigation responses for Earth
    threatening PHOs: a relatively quick flight time impulsive push
    (perhaps by an impacting spacecraft or a nuclear device) or a longer
    flight time rendezvous mission followed by either an impulsive or slow
    push technique (e.g., gravity tractor). If there is sufficient time,
    the longer flight time rendezvous is preferred because a resident
    spacecraft can provide both a verification that the asteroid is
    actually on an Earth threatening trajectory or not and it can verify
    that a deflection maneuver was successful. A nuclear device could be
    used in a stand-off mode where the explosion is above the asteroid's
    surface so that the resultant neutron radiation then ablates the
    asteroid's front side and introduces a thrust in the direction opposite
    to the vaporizing material. A far more efficient, but less controlled,
    technique could be achieved by placing the nuclear device upon, or
    below, the asteroid's surface. A nuclear response may be required for a
    large (larger than a few hundred meters) PHO that is found to be on an
    Earth-threatening trajectory and for which there is not sufficient time
    to use an alternate technique. This is a very unlikely scenario since
    the larger objects that might require a nuclear response are also the
    easiest to discover so a large Earth threatening object will likely be
    discovered many decades in advance of the potential impact event thus
    allowing the use of an alternate technology that lacks the problems of
    the nuclear option--problems that include launch safety, public concern
    and the possible necessity to modify existing treaties. The advantages
    of using a nuclear device are that one or more devices could deliver to
    an Earth threatening asteroid far more energy per kilogram of delivered
    (launch) mass than any alternative mitigation technique and the
    technology is mature. The disadvantages include the surface interaction
    of such a powerful impulsive device with a PHO of unknown structure,
    which would introduce an uncertainty in the deflection response and
    possibly a partial breakup of the asteroid itself. The latter scenario
    might introduce a shotgun-like effect upon the Earth unless the breakup
    and subsequent dispersal could be initiated soon enough prior to a
    potential collision that the vast majority of the small fragments would
    miss the Earth altogether. In short, a nuclear device option should be
    maintained as a viable mitigation technology but utilized only in the
    relatively rare situations when a more controlled deflection technique
    is not adequate or possible.

    Questions submitted by Representative Dana Rohrabacher

    Q1.  The need for a comprehensive potentially hazardous NEO program
    seems to require expertise of several agencies. How do you suggest
    coordination be handled?

    A1. NASA has been properly given the responsibility to discover, track
    and catalog near-Earth objects (NEOs) and to determine if any of these
    objects pose a future threat to Earth. For these efforts, a number of
    governmental and academic agencies have provided advice and expertise
    along with survey search and computing facilities. My suggestion would
    be to maintain NASA's lead role in these activities. In the event a
    potentially hazardous object (PHO) is found to be on an Earth
    threatening trajectory, a mitigation technology effort may be required.
    Such an effort would require that a spacecraft be built, launched,
    tracked and navigated to rendezvous with the PHO to monitor its motion
    and conduct a mitigation procedure if that were warranted. Within the
    U.S., only NASA has that type of experience so it would seem to me that
    NASA should be given the U.S. lead in mitigation technology planning as
    well. NASA should, of course, solicit suggestions and advice from other
    relevant agencies. In particular, should a nuclear deflection
    mitigation attempt become necessary, other U.S. agencies (e.g., DOD,
    DOE) would need to be intimately involved in the mitigation attempt.
        The threat of a PHO impact is an international problem and should
    have an internationally agreed upon solution. Such a threat could
    generate far more problems than just the technologies required for
    mitigation--including effective communication with the public and
    disaster preparedness. To my knowledge, there has been very little
    discussion within the international community to address the totality
    of the PHO threat issues. There is an ongoing activity within the
    Association of Space Explorers to address some of these issues and they
    plan to introduce a draft NEO deflection protocol to the Scientific and
    Technical Subcommittee of the U.N. Committee on the Peaceful Uses of
    Outer Space (COPUOS) during their 2009 session. One possible way
    forward would be the assignment of responsibility to a particular U.S.
    government agency to begin interagency discussions to define the NEO
    mitigation responsibilities of specific government agencies and to
    establish a recommended strategy for selecting a mitigation technology
    option. These U.S. discussions and recommendations would then need to
    be coordinated and integrated with those arising from the activities of
    the UN/COPUOS Scientific and Technical Subcommittee in 2009.

    Q2.  Describe some of the proposed mitigation techniques and their
    trade offs.

    Q3.  What is your assessment of the need for a nuclear deflection
    capability?

    A2,3. Some of the following discussion has been mentioned in response
    to Representative Feeney's question 5. For completeness, some points
    are repeated below.
        Viable mitigation techniques for deflecting Earth threatening
    asteroids can be grouped into two categories. The first category of
    mitigation techniques includes ``slow push'' technologies that are
    designed to change the asteroid's orbital velocity over relatively long
    periods of time. The second category includes impulsive events that are
    designed to change the asteroid's orbital velocity using the energy of
    an explosive device or the energy imparted to the asteroid as a result
    of a high velocity impacting spacecraft. Either category of mitigation
    technology would benefit from a rendezvous spacecraft that would be
    placed in orbit around, or hover near, the hazardous asteroid.
    Radiometric tracking of this ``monitor spacecraft'' could be used to
    dramatically improve the orbit of the asteroid and hence determine
    whether or not it was actually a threat to Earth. Should a deflection
    maneuver prove necessary, this monitor spacecraft could continue to
    track the asteroid during and after the deflection attempt to verify
    that the deflection was successfully carried out and the asteroid would
    indeed miss the Earth at the predicted impact epoch. Finally, in the
    very unlikely scenario that the deflection maneuver prevented an Earth
    impact at a certain future epoch number 1 but pushed it toward a tiny
    keyhole in space that would allow it to strike Earth at a subsequent
    impact epoch number 2, the monitor spacecraft could be used as a
    gravity tug to move the asteroid the few hundred meters necessary to
    prevent the asteroid from entering the impact plane keyhole. In short,
    if there is sufficient time, a monitor spacecraft should be maintained
    in the immediate neighborhood of the Earth threatening asteroid.
        Within the first category of slow push techniques, there are only a
    few viable methods that could be used including the ``tugboat''
    approach where the spacecraft attaches to the asteroid and uses its
    thrusters to slowly tow it and the so-called gravity tractor where a
    massive spacecraft uses its thrusters and the gravitational attraction
    between the spacecraft and asteroid to gently pull the asteroid and
    alter its orbital velocity and position in space. The tugboat approach
    presents significant engineering challenges in that it must first
    secure the asteroid in its grip, and then tow it using its thrusters,
    being careful to thrust only when the asteroid's rotation brings it
    back to the same position in space. The gravity tractor approach, with
    its tiny pull capability, needs to be very close to a rotating
    irregular asteroid so it has challenges in safely maintaining the
    necessary close proximity to the asteroid. Some attention has been
    given to other slow push techniques including solar concentrators or
    pulsed lasers that could focus intense radiation on the asteroid,
    ablate or vaporize the near side material and thus introduce a small
    thrust in the opposite direction from the material that is streaming
    off the asteroid's side nearest the solar concentrator or laser device.
    Both of these techniques would provide significant engineering
    challenges and each system would have vaporizing material driven back
    toward the devices themselves--thus attenuating the intensity of the
    focused radiation and perhaps contaminating the system's optics.
        Within the second category of impulsive deflection techniques, the
    high velocity spacecraft impact and the explosive device impulse
    techniques (including nuclear devices) are mature technologies. A high
    velocity impact of a spacecraft with comet Tempel 1 was successfully
    carried out by NASA in July 2005 so the autonomous navigation
    technologies for such a deflection technique have already been
    demonstrated. However, a high velocity impact of a spacecraft with a
    target asteroid will produce only a modest change in the asteroid's
    velocity and is only a useful technology if the asteroid is smaller
    than a few hundred meters in diameter or there are many years available
    between the deflection attempt and the predicted Earth impact.
        One or more nuclear devices could be used in a stand-off mode where
    the explosion is above the asteroid's surface so that the resultant
    neutron radiation then ablates the asteroid's front side and introduces
    a thrust in the opposite direction to the vaporizing material. A far
    more efficient, but less controlled, technique could be achieved by
    placing the nuclear device upon, or below, the asteroid's surface. This
    nuclear response may be required for a large (larger than a few hundred
    meters) PHO that is found to be on an Earth threatening trajectory and
    for which there is not sufficient time to use an alternative technique.
    The advantages of using a nuclear device are that one or more devices
    could deliver to an Earth threatening asteroid far more energy per
    kilogram of delivered (launch) mass than any alternative mitigation
    technique and the technology is mature. The disadvantages include the
    interaction of such a powerful impulsive device with the surface of a
    PHO of unknown structure, which would introduce an uncertainty in the
    deflection response and possibly a partial breakup of the asteroid
    itself. The latter scenario might introduce a shotgun-like effect upon
    the Earth unless the breakup and subsequent dispersal could be
    initiated soon enough prior to a potential collision that the vast
    majority of the small fragments would miss the Earth altogether. In
    short, a nuclear device option should be maintained as a viable
    mitigation technology but utilized only in the relatively rare
    situations when a more controlled deflection technique is not adequate
    or possible.

                       Answers to Post-Hearing Questions

    Responses by Donald B. Campbell, Professor of Astronomy, Cornell
            University; Former Director, Arecibo Observatory

    Questions submitted by Chairman Mark Udall

    Q1.  The asteroid Apophis has been identified as an object that has a
    small chance of impacting Earth in 2036. What role will Arecibo play in
    improving our understanding of Apophis and refining predictions of a
    potential impact?

    A1. During the close approach of Apophis to the Earth in 2013 at a
    distance of about nine million miles, it is my understanding that radar
    observations with Arecibo and Goldstone combined with optical
    measurements will significantly reduce the probability of a potential
    impact during its passage by the Earth in 2036. Arecibo observations in
    2013 will provide some information about Apophis's size but its large
    distance will preclude the high resolution characterization
    measurements that would provide detailed information about its shape
    and size.

    Q2.  Your testimony notes that ``No study has been done of the precise
    role that the Arecibo radar and how many hours of NEO observations will
    be needed when the new, high sensitivity searches commence. . .. This
    needs to be done.'' What, specifically, would such a study entail, what
    entity or entities would be capable of conducting it, and how much time
    do you believe such a study would require?

    A2. Such a study would entail determining the number and distribution
    of the hours of use of the radar system on the Arecibo telescope that
    would be needed for follow-up astrometric and characterization
    observations of newly discovered NEOs once the Pan-STARRS and LSST NEO
    searches are underway. Such a study would be best carried out by the
    National Astronomy and Ionosphere Center, which operates the Arecibo
    Observatory for the NSF, with input from the scientists involved with
    NEO radar observations and orbit determination at Arecibo and the Jet
    Propulsion Laboratories. The first Pan-STARRS system is expected to
    come online in the next year leading to a significant increase in the
    NEO detection rate. Direct experience with this system will provide the
    best guide as to the needed increase in the hours of operation of the
    Arecibo radar. Based on this, the study should be completed by early
    2009.

    Q3.  What is the estimated cost of decommissioning the entire Arecibo
    observatory and what is the estimated time that would be required to
    disassemble the facility?

    A3. There is no current reliable estimate for the cost of
    decommissioning the entire Arecibo Observatory. The National Science
    Foundation has contracted for a study of the decommissioning costs. My
    understanding is that the contractor will deliver their report to the
    NSF in February, 2008.

    Questions from Representative Tom Feeney

    Q1.  NASA's NEO report, delivered this March, provides several options
    for meeting the goal of achieving 90 percent detection, tracking and
    characterization of Potentially Hazardous Objects, and the report
    establishes a clear relationship between the resources invested and the
    time needed to achieve 90 percent coverage. In essence, the report
    shows that for an additional investment of $536 million, we could buy
    down a decade of time to complete the survey. In your view, is that
    additional investment necessary? Does the threat posed by PHOs compel
    faster completion of the survey?

    A1. Given the relatively low probability in any given year of an impact
    by a NEO, in my view significant expenditures to complete the survey in
    a shorter time period are not justified. If significant cost savings
    can be achieved by extending the deadline a small number of years
    beyond 2020 then this should be seriously considered. Dr. Tyson's
    testimony indicated that by devoting 15 percent of the observing time
    on the LSST to NEO searches the 90 percent requirement could be
    achieved in about 12 years. Assuming that the LSST begins operations in
    2014, this would mean a completion of the survey by 2026. This date
    does not include contributions from other searches such as Pan-STARRS.
    Providing partial support for the construction and operating costs of
    the LSST for a NEO survey would appear to be a cost effective method
    for completing the survey.

    Q2.  What are the most difficult NEOs to detect? Is there, for
    instance, a portion of the sky that won't be covered by ground-based
    facilities? Are there certain types of orbits that make it difficult to
    detect and track asteroids and comets?

    A2. NEOs whose orbits are primarily interior (i.e., closer to the Sun)
    to Earth's orbit are more difficult to detect from Earth than those
    NEOs that spend most of their time outside the Earth's orbit because
    they need to be observed shortly after sunset or shortly before
    sunrise.

    Q3.  Once the LSST and Pan-STARRS telescopes are operating, and surveys
    for PHOs that are 140 meters or larger has commenced, what is the
    business and public safety case for expanding the search to detect and
    track smaller PHOs--for instance, down to size 50 meters? What are the
    costs and schedule implications?

    A3. As discussed during the Hearing, the difficulties of finding NEOs
    increases as their size gets smaller. The 140 meter size limit for 90
    percent completion seems a sensible and achievable goal for now in
    terms of the potentially available resources and costs. As pointed out
    by Mr. Schweickart, this search, if it is carried out, should also find
    close to 50 percent of objects down to 50m in size. As the search
    progresses, the issues related to a ``complete'' survey of smaller NEOs
    can be realistically addressed and decisions made.

    Q4.  You state that Cornell was required by NSF to seek other funding
    commitments to fill the void left by NSF's reduction. What has been
    Cornell's experience finding new funding? Are you optimistic that other
    sources will be found?

    A4. Cornell representatives are in ongoing discussions with
    governmental and educational bodies in Puerto Rico and they are
    moderately optimistic that funding for programs that enhance the role
    of the Arecibo Observatory in education and public outreach can be
    obtained through, or in collaboration with, Island institutions.
    However, these programs would not, and should not, be a substitute for
    the observatory's basic research mission. It appears very unlikely that
    year-on-year funding can be obtained from sources within Puerto Rico or
    elsewhere to partially support the operation of the observatory as a
    federally owned and funded scientific research institution except
    possibly, in the case of the observatory's planetary radar program,
    from NASA.

    Q5.  One deflection solution, suggested by NASA, is to detonate a
    nuclear device in the vicinity of a PHO. What are the advantages and
    disadvantages of this approach? What circumstances would argue against
    using a nuclear device in lieu of alternative approaches?

    A5. I have not spent adequate time studying this issue to make an
    informed response to the question.

    Questions submitted by Representative Dana Rohrabacher

    Q1.  With regard to NASA's Spaceguard program, what changes, if any, do
    you recommend to make the program more effective? In your view, is
    further legislation required from Congress to implement needed changes?

    A1. I am not directly involved with NASA's current Spaceguard program
    aimed at discovering 90 percent of NEOs with sizes larger than one km.
    This program was a search program and appears to be largely achieving
    its objectives. It is now important to move to the next stage currently
    under discussion, the discovery of 90 percent of NEOs larger than 140m,
    determination of which ones are truly potentially hazardous via orbit
    determination and the investigation of possible mitigation schemes
    based on characterization studies.

    Q2.  How important do you consider characterization in the overall NEO
    issue priorities?

    A2. Characterization has two objectives: 1) The understanding of the
    range of properties exhibited by NEOs to inform the design of
    mitigation strategies; 2) The characterization of specific objects that
    pose a definite threat to Earth so that the appropriate mitigation
    strategy can be implemented. The first of these is ongoing and the
    coming more sensitive searches will potentially provide a larger range
    of asteroid characteristics to be included in mitigation studies. These
    studies need to be pursued. For the second case, clearly the
    identification of PHOs via searches coupled with precise orbit
    determination to identify any objects that truly do threaten Earth
    comes first with characterization an input to mitigation planning.

    Q3.  What capabilities are required for a comprehensive deflection
    campaign?

    A3. As discussed by Mr. Schweickart and others, the technology needed
    for a comprehensive deflection campaign largely already exists. What is
    missing is a program with clear responsibility for its implementation
    vested in one organization.

    Q4.  What is your estimate of the number of undiscovered asteroids in
    the 140 meter and above range? Describe the potential damage that an
    asteroid in the 140 meter range can cause striking an ocean within,
    say, 500 miles of a U.S. coast?

    A4. The March 2007 NEO Report to Congress gives the estimated number of
    NEOs greater than 140m in size as approximately 100,000. The impact
    energy for a 140m NEO would be about 100 megatons of TNT equivalent.
    Published studies have shown that the release of this much energy as a
    result of an impact into the ocean would certainly have the potential
    for a very serious consequences to the local and, perhaps, distant
    seaboards.

    Q5.  Asteroids are more easily detected in the infrared spectrum. An
    asset such as the WISE satellite has an effective capability for
    searching for NEO's infrared output. Is WISE being tasked for this
    role? What other infrared detection devices can or will be used to
    detect NEOs?

    A5. I am not involved with the WISE satellite program. This question
    would be better answered by NASA.

    Q6.  Could you describe some of the losses that might occur to U.S.
    research in radio and radar astronomy, and atmospheric sciences if the
    facility were to close as threatened by one of the supporting NSF
    directorates? How is the telescope unique? What unique research
    opportunities does Arecibo offer the U.S. and global scientific
    community? What new research is scheduled and proposed for Arecibo?

    A6. Arecibo is the world's largest single dish radio telescope with
    sensitivity in its frequency band that is four to five times higher
    than any other single dish radio telescope. It is also unique in that
    it is equipped with two very high powered transmitters used for radar
    studies of solar system bodies including NEOs and for studies of the
    Earth's ionosphere. Its great sensitivity has allowed Arecibo to play a
    critical role in the study of pulsars with one notable example being
    the discovery of the binary pulsar PSR 1913+16 for which timing
    measurements, also using Arecibo, gave the first strong evidence for
    the existence of gravitational waves. Russell Hulse and Joseph Taylor
    received the Noble prize in 1993 for this work. Arecibo's sensitivity
    will continue to make it a major contributor via pulsar observations to
    study of gravitational waves, tests of General Relativity, the
    properties of nuclear matter in neutron stars, the electron density
    distribution and magnetic fields in our galaxy and, potentially, black
    holes via the hoped for discovery of a black hole--neutron star (i.e.,
    pulsar) binary system.
        Because of it sensitivity, Arecibo is the only radio telescope than
    can study gas (i.e., neutral hydrogen in distant galaxies) over a
    cosmologically significant volume allowing it to study how gas and dark
    matter are distributed and evolve through cosmic time. This is one of
    the major current research programs at the Arecibo Observatory with
    participants from a significant number of universities and research
    institutions in the U.S. and abroad.
        Arecibo's ionospheric research program is supported by the NSF
    Division of Atmospheric Sciences. Arecibo is the most sensitive
    component of a chain of incoherent scatter ionospheric radars supported
    by the NSF stretching from the polar regions to the magnetic equator.
    The results from coordinated observations by all the participants in
    the chain provides input into ionospheric modeling programs the results
    of which impact the study of Space Weather and are potentially
    important for climate change studies. Arecibo's location allowing it to
    study the ionosphere at mid-magnetic latitudes makes it a unique
    contributor to this effort.
        Arecibo is one of only two high powered radar systems with the
    capabilities for studying solar system bodies and it is the most
    sensitive by a factor of about 20. It makes major contributions to the
    orbit determination and characterization for NEOs including comets, to
    studies of the surfaces and internal structure of the Moon and
    terrestrial planets, and to the study of planetary satellites.
        The closing of the world's largest radio telescope means that its
    great sensitivity will not be available for the ongoing research work
    described above or for other continuing research efforts. Perhaps just
    as importantly, it also means that Arecibo will not be available to
    pursue new research opportunities that may arise in the future that can
    be best exploited by utilizing a telescope with Arecibo's sensitivity.
    The discovery of pulsars is a classic example, it was almost as if the
    designers of the Arecibo telescope had pulsar research in mind before
    pulsars were discovered.

    Q7.  Please describe some of the resources that Arecibo provides for
    discovery and research programs and examples of results.

    A7. As described above, Arecibo's huge collecting area makes it the
    most sensitive single dish telescope in the world. Its two high powered
    transmitters give it unique capabilities for radar studies of solar
    system bodies and the Earth's ionosphere. The Observatory is also
    equipped with an array of optical instruments that are used for studies
    of the lower part of the ionosphere.
        Among Arecibo's many accomplishments are: 1) the discovery of a
    significant number of known pulsars including the binary pulsar that
    led to our best indication that gravitational radiation exists and the
    first milli-second period pulsar, a class of very fast rotating pulsars
    that are the most precise pulsar ``clocks'' needed, for example, in the
    proposed pulsar gravitational wave ``observatory''; 2) The discovery of
    the first planets around another star, in this case a neutron star; 3)
    The mapping of the structure of the local universe from redshift
    (recessional velocity) measurements based on observations of neutral
    hydrogen in galaxies; 4) The discovery that Mercury rotates 1.5 times
    for each orbital ``year'' about the Sun and, in conjunction with the
    Goldstone radar and the NSF Green Bank Telescope, that Mercury has at
    least a partially molten core; 5) The first mapping of the surface of
    Venus at high enough resolution to study its surface features; 6)
    Confirmation of the existence of binary NEOs; 6) The confirmation of
    the Yarkovsky leading to a revolution in our ideas on how small
    asteroids move from the main asteroid belt between Mars and Jupiter
    into the inner solar system to become NEOs; 7) Detailed studies of the
    electron density distribution, temperature, winds and composition of
    the Earth's ionosphere.

                       Answers to Post-Hearing Questions

    Responses by J. Anthony Tyson, Professor of Physics, University of
            California, Davis; Director, Large Synoptic Survey Telescope
            Project

    Questions submitted by Chairman Mark Udall

    Q1.  Your testimony notes that by making adjustments to the LSST
    observations, the expanded NEO survey could be completed within 12
    years and that ``the current cost estimate for LSST in 2006 dollars is
    $389M for construction and $37M per year for operations. For a 12-year
    long survey, the 15 percent of the total cost is $125M.'' What is the
    breakdown of the $125M estimate for the NEO-related activities, and is
    it inclusive of the 12-year operations? How confident are you of that
    cost estimate, and why?

    A1. The LSST construction and operations budget are based on proven
    estimating practices of dividing the entire project into over 1,000
    individual work tasks and obtaining documented cost estimates on each
    task either from commercial vendor estimates or engineering estimates.
    The total cost estimate also contains a 30 percent contingency to
    absorb unexpected technical problems and/or higher costs than estimated
    today. The costing process and the estimates have been peer reviewed
    and endorsed by an NSF panel of external experts. The $125M figure was
    calculated from the extra effort in an LSST survey of the sky required
    to reach the Congressional goal of 90 percent completeness for
    Potentially Hazardous Asteroids (PHA) of 140 meter diameter and larger.
    This extra effort was quantified through multiple simulations of LSST
    operations. We are confident that this is an accurate estimate of the
    level of effort required. This extra effort devoted to the PHA
    discovery program amounts to $120M during operations, plus $5M for
    development of advanced orbit linking and operations pipeline software.
    The $120M is inclusive of the added PHA portion of operations during
    the full 12-year survey.

    Q1a.  Your testimony also mentions that ``To keep LSST on schedule,
    about $5M should be spent on optimized NEO orbit software pipeline
    development in the last phase of R&D and the construction phase. . ..''
    Is this funding included in the $125M overall cost required to modify
    LSST for the NEO survey?

    A1a. Yes.

    Q1b.  When would the required software development for the NEO survey
    need to begin in order to start the Survey in 2014, assuming LSST
    commences operations at that time?

    A1b. 2009.

    Q1c.  What approvals and funding are required before LSST can be
    developed and how confident are you that LSST will be ready for
    operations in 2014-2015, as noted in your testimony?

    A1c. The LSST project has been funded for R&D by the NSF. The
    construction proposal to the NSF was reviewed in September 2007 and the
    project had been recommended to move on to the next milestone review in
    the fall of 2008. At this time we are on track for NSF construction
    start in FY 2011. Long lead sub-component fabrication has begun (such
    as the $21M primary mirror), with private funding.

    Q2.  You testified that ``with LSST, one sees each one of these
    asteroids 100 to 200 times, even more. So, it is possible to derive a
    pretty good orbit for those, and distinguish them from the
    background.'' What is the level of accuracy in NEO orbits that you
    estimate would be possible with LSST? What implications, if any, would
    this have for further orbital determination from planetary radar
    facilities.

    A2. In very general terms, the orbits from a single apparition set of
    observations will be good enough for the NEO to be predicted and
    located again any time it comes within range for the next several
    decades, and the path can be predicted well enough to rule out any
    future impact with the Earth for many decades to come, for the vast
    majority (over 99 percent) of detected objects. However, there will be,
    as there are now (e.g., the asteroid Apophis) cases where the optical
    position data will be unable to rule out a future impact, and radar
    facilities will be key assets for providing the observations needed to
    rule out (or in, if we should be unlucky) future impacts for a small
    number of cases. It can be expected that radar will continue to be
    needed for a similar number of key observations in the future as it has
    been in the past. Radar however cannot be used to survey the sky and
    discover PHAs.

    Questions submitted by Representative Tom Feeney

    Q1.  NASA's NEO report, delivered this March, provides several options
    for meeting the goal of achieving 90 percent detection, tracking and
    characterization of Potentially Hazardous Objects, and the report
    establishes a clear relationship between resources invested and the
    time needed to achieve 90 percent coverage. In essence, the report
    shows that for an additional investment of approximately $536 million,
    we could buy-down a decade of time to complete the survey. In your
    view, is that additional investment necessary? Does the threat posed by
    PHOs compel faster completion of the survey?

    A1. One can hasten the survey to some degree with greater expenditure
    on other complementary systems. However, there is a natural limit to
    the minimum time that a survey can be completed to, say 90 percent,
    which results from the fact that the asteroids move in orbits with
    orbital periods of several years and often spend years at a time simply
    out of the range of visibility from the Earth, or in some cases, even
    from space. Thus, it is not possible with any detection system, no
    matter how capable, to see all PHAs instantly, or even in a very short
    time. The fundamental ``time constant'' for surveying is the timescale
    of the orbit periods, that is, a few years. This amounts to the
    ``exponential time constant'' of a survey, and to reach 90 percent
    takes a factor of two or three times the time constant, or about a
    decade. Speeding things up from a decade requires near-Herculean
    effort, for example putting a rather large telescope in a ``Venus-
    like'' orbit, and even that reduces the time by only a few years. On
    the other hand, time is our friend if we consider going a little more
    slowly. Thus, backing off to a capable ground-based survey can reach
    the goal set by Congress in only a few years longer than the 15 years
    (from 2005) originally mandated by the Congress. It is more important
    not to back off in the completeness level than in the time to achieve
    it. I share the opinion of many in the NEA community that it is key to
    get started now on a capable survey, but that it is not worth the
    investment in a space facility to shorten the survey by a few years.

    Q2.  What are the most difficult types of NEOs to detect? Is there, for
    instance, a portion of the sky that won't be covered by ground-based
    facilities? Are there certain types of orbits that make it difficult to
    detect and track asteroids and comets?

    A2. Some NEOs are more difficult to detect than others, although
    ``blind spots'' in the sky not covered by the surveys is not the cause
    of that difference. Any asteroid in an orbit that can hit the Earth
    will spend some time in the visible part of the sky, so it is only a
    matter of time before it passes into a visible region. The goal of the
    survey is to find PHAs decades before an impact, not on final approach
    only days before an impact. In the latter case, yes, an impactor can
    arrive from the direction of the sun and not be seen until it hits. But
    in the former case, during a close (but not impacting) pass by the
    Earth, if it comes from the direction of the sun it will become visible
    after closest approach as it moves away, and vice versa if it comes
    from outside moving in. Thus, in either case, it will be seen by the
    survey and duly cataloged for any future approaches or impact paths.
    The difficulty of finding PHAs is therefore mostly a matter of how
    often an asteroid passes within range of the survey. One class that is
    difficult are objects in very long orbits, similar to comets, that only
    come in close to the Earth every decade or so. We simply have to wait
    until they come around. Another group are resonant objects that have
    orbit periods that are close to multiples (including 1.0) of the
    Earth's orbit period. Imagine an asteroid with a period very near 5.0
    years, which comes close to the Earth's orbit when the Earth is on the
    other side of the sun. Every five years it is behind the sun, so we
    can't see it. At other times it is far from the sun (and also the
    Earth), so even when it is in the view range of the survey it is very
    faint. Yet another group are asteroids with very nearly 1.0 year orbit
    period. A number of these have been discovered which appear to ``loop''
    the Earth in eccentric or inclined orbits. These objects drift away
    from the Earth's vicinity after several annual loops, not to return
    again for decades or longer, after they lose or gain one full circuit
    of the sun relative to the Earth. There are undoubtedly other such
    objects currently parked on the opposite side of the Earth's orbit that
    will slowly drift into near-Earth space, and could be an impact hazard,
    but we cannot find them from the Earth until after they move out from
    behind the sun. Nevertheless, an Earth-based survey would find them
    years before any possible impact. One can find them sooner with a
    space-based survey in a different heliocentric orbit (say near Venus),
    but is it worth it? It is improbable that there is even one object as
    large as one km in diameter, and maybe only a few larger than 140m, in
    such orbits, so the value of taking the extra effort to find them is
    questionable.
        Finally, comets are intrinsically difficult to track, due to the
    non-gravitational forces of the gasses being emitted. Thus, it would be
    impossible to predict an impact with certainty very long in advance
    even if we found a rare comet on a potentially collision course. And of
    course the long-period comets come around less than once in a lifetime,
    so new ones never seen before keep coming. Finding and cataloging
    comets far in advance of an impact is thus not possible with today's
    technology or any foreseeable technology.

    Q3.  Once the LSST and Pan-STARRS telescopes are operating, and surveys
    for PHOs that are 140 meters or larger has commenced, what is the
    business and public safety case for expanding the search to detect and
    track smaller PHOs--for instance, down to a size of 50 meters? What are
    the cost and schedule implications?

    A3. In my response to question 1 above, one can see that there is a
    clear diminishing return in value for cost of ever larger surveys of
    ever smaller PHAs. See also the NASA report on the feasibility of
    extending the search for near-Earth objects to smaller limiting
    diameters: http://neo.jpl.nasa.gov/neo/report.html The first generation
    ``Spaceguard'' survey has reduced the impact risk from about 1,000
    casualties per year to about 100 per year, at a cost of a few tens of
    millions of dollars. This is certainly quite good value returned. The
    next generation survey, to 140 meter diameter, should reduce risk by
    another 90 casualties per year, at a cost of some hundreds of millions
    of dollars. The cost/benefit ratio of such a survey appears to be in a
    justifiable range that is worthy of policy consideration. A further
    step, say to 50 meter diameter, would seem on the face of it to be
    beyond the range of what could be justified on a cost/benefit basis. In
    terms of cost and schedule, we do not possess the technology at present
    to catalog 50 meter objects at large enough distances to find a large
    fraction of them in, say, ten years at reasonable cost. However, the
    same systems that find 90 percent of objects larger than 140 meters in
    ten years will find 90 percent of objects to 50 meters diameter over a
    longer time, of order of a human lifetime. So by about 2100, we will
    eventually find nearly every PHA that can make it through the
    atmosphere. That is sooner than the odds of the next one hitting the
    Earth, so the level of patrolling of the skies contemplated by LSST
    will very likely find the next impacting object before it finds us.

    Q4.  One deflection solution, suggested by NASA, is to detonate a
    nuclear device in the vicinity of a PHO. What are the advantages and
    disadvantages of using this approach? What circumstances would argue
    against using a nuclear device in lieu of alternative approaches?

    A4. Many of the implications of this question are matters of policy
    rather than science. However, there are technical aspects. My comments
    are based on the 2006 NASA NEO workshop in Vail. A major disadvantage
    of nuclear approaches is that we do not know how efficient a nuclear
    standoff explosion might be, or if it would disrupt the body into
    fragments still largely traveling on the same path, or if it would push
    it aside, as proposed. Thus, one cannot know in advance whether a
    standoff explosion would be effective, or even if shown to be effective
    in a test case, whether it would be equally effective on another
    asteroid--the one actually coming our way. The same uncertainty
    accompanies the ``kinetic impactor'' method of deflection, but it is
    vastly more politically acceptable to conduct impact experiments, such
    as the ``Deep Impact'' comet mission, than it would be to conduct
    nuclear tests in space. Furthermore, the most likely scenario we may be
    faced with is the case of an object that may, but with less than 100
    percent certainty, be on a collision course, but we will not know for
    sure until after the optimum time to take action. In such a case, it
    would be politically difficult, as well as strategically dangerous, to
    take action with nuclear explosions when such action might not be
    needed at all, and even if so could produce unpredictable results. Much
    more prudent would be an approach that is more controllable and can be
    monitored for effect, such as the proposed combination of a rendezvous
    vehicle that can monitor the effect of a kinetic impactor and serve as
    a ``gravity tractor'' as needed for fine-tuning the deflection. In any
    case, one should weigh the benefit of developing deflection plans in
    advance of a discovered need.

    Questions submitted by Representative Dana Rohrabacher

    Q1.  With regard to NASA's Spaceguard program, what changes, if any, do
    you recommend to make the program more effective? In your view, is
    further legislation required from Congress to implement needed changes?

    A1. The Pan-STARRS and LSST surveys are planned to use somewhat
    different search patterns, and object identification algorithms, than
    those used by the current surveys. Whether it would be cost-effective
    to implement changes of this nature in the current surveys is
    questionable when they will become obsolete in terms of depth of survey
    very soon anyway. It would certainly be short-sighted to shut down the
    current surveys in anticipation of the next generation before those
    surveys come on line at some decent level, but NASA, and the Congress,
    should be prepared to make the transition to the next generation as
    soon as it is possible to do so. To retire the risk from Potentially
    Hazardous Asteroids, Congress could do two things: (1) assure that a
    ground-based survey capable of achieving 90 percent completeness for
    PHAs of larger than 140 meters gets started as soon as possible and,
    (2) assure availability of the Arecibo radar (since that will continue
    to be an occasionally essential asset into the next generation of
    surveys.)

    Q2.  How important do you consider characterization in the overall NEO
    issue priorities?

    A2. Physical observations, to measure sizes, shapes, spins, densities,
    mineralogy, and so forth of discovered asteroids is of very high
    scientific interest, but is of secondary importance as far as the
    impact hazard issue is concerned. The statistical characterization
    method has serious limitations when a robust characterization of that
    particular asteroid with our name on it is required. Characterizing a
    statistically meaningful subset of discovered objects is necessary in
    order to understand the population (for example, to even know what
    fraction of objects larger than a given size have been discovered), but
    this can be done from observations of a small fraction of the
    discovered population that happens to be most easily observable, thus
    it is not necessary to have a large commitment of telescopes as large
    or even larger than the survey instruments, as has sometimes been
    claimed. This is not to say that no commitment is needed, but it can be
    satisfied with existing facilities currently engaged in asteroid
    observations.

    Q3.  What capabilities are required for a comprehensive deflection
    campaign?

    A3. This is outside the purview of the LSST project. While R&D is
    needed, my personal opinion is that deployment of deflection hardware
    should wait until a demonstrated need is discovered.

    Q4.  What is your estimate on the number of undiscovered asteroids in
    the 140 meter and above range? Describe the potential damage that an
    asteroid in the 140 meter range could cause striking an ocean within,
    say, 500 miles from a U.S. coast.

    A4. It is estimated that there are about 20,000 NEAs larger than 140
    meter in diameter, and presently, there are somewhat over 3,500 known,
    leaving about 17,000 undiscovered. In terms of Potentially Hazardous
    Asteroids, there are approximately 4,000 total estimated, and about 600
    known. A 140 meter diameter asteroid striking the ocean 500 miles (800
    km) from shore might produce a tsunami wave a meter or two in height as
    it approaches the shore. The ``run up'' amplification depends a great
    deal on the off-shore depth profile, but might be a factor of two or
    three, to a height of five meters or so. Such a wave might run inland a
    km or so, depending on the flatness of the land on shore. The effects
    of such an impact tsunami could be comparable to a major hurricane, and
    the chance that the impact would be at a particularly vulnerable
    location rather than somewhere else is comparable to that for a
    hurricane.

    Q5.  Asteroids are more easily detected in the infrared spectrum. An
    asset such as the WISE satellite has an effective capability for
    searching for NEO's infrared output. Is WISE being tasked for this
    role? What other infrared detection devices can or will be used to
    detect NEOs?

    A5. Infrared technology is not yet mature enough to be competitive with
    optical (reflected sunlight) surveying. From the ground, the highly
    emissive and absorbing atmosphere reduces thermal IR sensitivity to
    less than that of optical, regardless of detector technology. From
    space, IR has a modest theoretical advantage, less than one might
    suppose because the resolution of a given aperture telescope in the
    thermal IR is about twenty times less than at visible wavelengths, and
    the background level of sky brightness and confusing sources, after
    allowing for the reduced resolution, is substantial. There are some
    technological problems: detector arrays are not yet as large as those
    for optical wavelengths, to operate efficiently they need to be cooled
    to the limit (or beyond) of passive cooling systems, and with many
    images each with billions of pixels there would be on-board computation
    challenges.
        While WISE will survey the entire sky and, indeed, detect many
    asteroids, there are a number of reasons that it will not be capable of
    making a substantial contribution to the PHA survey. First, the WISE
    survey strategy does not have a cadence that is tuned to discovering
    and cataloging moving objects. Moreover, with only a six-month mission,
    many PHAs will be out of range and completely unobservable during the
    brief period of mission operations. Finally, its modest instrument (0.4
    meter aperture, 0.8 degree field of view) is not well-suited for this
    purpose. However, WISE will make great strides in the realm of asteroid
    characterization. The four separate IR band passes will allow the
    characterization of a large number of asteroids, some of which may not
    be actually discovered until later. This information, combined with
    optical catalogs, such as the Sloan Digital Sky Survey, will enable
    subsequent PHA surveys such as LSST to make good statistical inferences
    about the makeup and size of new discoveries. WISE will detect a lot of
    asteroids, but is not capable of replacing even present optical survey
    systems, let alone systems like Pan-STARRS or LSST, even if re-tasked
    solely to the NEA survey. The advance of IR technology should be
    monitored for its potential to contribute to NEA surveys, but at
    present it does not appear to be mature enough to contemplate changing
    from ground-based optical surveys to space-based IR surveys.

                       Answers to Post-Hearing Questions

    Responses by Russell ``Rusty'' L. Schweickart, Chairman and Founder,
            B612 Foundation

    Questions submitted by Chairman Mark Udall

    Q1.  How well understood are the potential approaches to deflecting
    asteroids? What is the confidence level in the technologies that would
    be required? What information is needed to assess the various
    approaches, and how will decisions be made on which mitigation strategy
    to take?

    A1. The basic elements of an asteroid deflection are quite well
    understood. One must alter the orbit of the asteroid to 1) miss a
    direct Earth impact, and 2) avoid passing through any of the hundreds
    of return keyholes as the asteroid passes by the Earth. The
    technologies which have the required capability for the first of these
    objectives are kinetic impact (KI) and nuclear stand-off explosion. KI
    is essentially running into the asteroid in a specific direction with a
    specific velocity, similar to what was done in 2005 by the Deep Impact
    spacecraft running into comet Tempel 1. A stand-off nuclear explosion
    in space has never been done but on a theoretical basis should work.
    Both techniques can be characterized as strong but imprecise. Therefore
    essentially all asteroids which might threaten impact can be deflected
    from a primary impact (98-99 percent can be deflected using KI).
    However such a deflection has no possibility of insuring that the
    asteroid will not pass through any of hundreds of return keyholes
    resulting in a certain impact within several years. Therefore a
    precision deflection capability using the gravitational tractor (GT)
    concept (or other if any become available) is needed to immediately
    follow-up the imprecise primary deflection to insure that no keyhole
    passage is permitted.
        There need to be detailed analytic assessments and simulations
    performed on all three techniques. The KI and GT techniques should
    ultimately be flight tested on a real (but non-threatening) asteroid to
    fully validate a deflection campaign. I do not recommend demonstrating
    the nuclear explosion concept, although simulations could, and should
    be run.
        An actual deflection decision is virtually independent of the
    technology. A deflection campaign would require two coordinated
    missions, first a transponder/gravity tractor (t/GT) mission to
    precisely pin down the asteroid orbit and confirm a pending impact. If
    confirmed the t/GT would observe the subsequent KI impact from a safe
    distance, then pull in close to the asteroid to 1) confirm a successful
    primary deflection, and 2) determine whether or not the asteroid is
    headed for a return keyhole. In the unlikely case that the asteroid is
    headed for a keyhole the t/GT would then be employed to make a small
    but precise modification in the asteroid's new orbit to assure the
    asteroid misses the keyhole. This sequence is the only way, using
    existing technology, to guarantee a successful deflection. In the
    extremely improbable event (probability of occurrence once per 100,000+
    years) that the asteroid at issue is too large for a KI deflection, a
    nuclear stand-off explosion would be needed as a substitute. The
    precision component (t/GT) would still be essential to the success of
    the deflection campaign.
        The decision to deflect, per se, would of necessity be an
    international decision due to the inherent shifting of risk from one
    geographic region to another during any deflection. The Association of
    Space Explorers (ASE) is working on the deflection decision process in
    cooperation with the United Nations. While the action will of necessity
    be the responsibility of one or more space-faring nations, the decision
    process will involve many nations since the uncertainty in the impact
    point and the shifting of risk during any deflection will involve
    nations across the planet.

    Q2.  How mature are the non-nuclear versus the nuclear technologies for
    deflecting an asteroid?

    Q2a.  What should the priorities be in further developing those
    technologies?

    A2a. The non-nuclear (KI) technology is a flight proven technique
    having been used (albeit for different purposes) during the Deep Impact
    mission of July 4, 2005. The primary difference is that comet Tempel-1
    (the target of the Deep Impact spacecraft) was significantly larger
    than those asteroids likely to require deflection. Furthermore there is
    an unknown (likely small) possibility of fragmentation of the asteroid.
    Finally the ``momentum multiplier,'' the degree to which the ejection
    of debris from the kinetic impact multiplies the effectiveness of the
    impact, is highly variable and uncertain. The last two factors can, and
    should, be validated by an actual demonstration mission.
        The nuclear stand-off explosion is entirely theoretical. While
    terrestrial weapons effects analysis is a highly developed and
    sophisticated field of knowledge the use of nuclear explosions in space
    is not well understood and cannot, without modification of existing
    treaties, be tested. Proponents of the use of nuclear explosions
    generally feel very confident in their computer models, but atmospheric
    and vacuum explosions are very different from one another. Additionally
    the concerns mentioned above re KI also apply to the nuclear option,
    i.e., the possibility of fragmentation and the uncertainty of the
    ``multiplier'' effect. The primary difference in eliminating these
    uncertainties is that there is no impediment to testing KI in a
    demonstration mission whereas demonstrating a nuclear stand-off in an
    actual mission would be a major international political challenge, not
    to mention arguably a treaty violation.
        The gravity tractor (GT) is not in a ``versus'' situation, being a
    necessary component of any deflection campaign, nuclear or non-nuclear.
    In terms of technology maturity the primary challenge for the GT is
    engineering the control and guidance software for the ``towing''
    maneuver. Engineering simulations of the GT are about to get underway
    and testing should be done in an actual flight demonstration. A
    slightly modified Don Quixote mission (a NEO deflection mission
    considered by the European Space Agency) could simultaneously
    demonstrate both the KI and t/GT concepts.
        Priority should clearly be given to developing and testing the KI
    and t/GT concepts since they are the most likely to be called on for
    deflection. Only one to two percent of potential deflection challenges
    would require a nuclear option and that percentage will drop
    essentially to zero as the revised search program is executed over the
    next 15-20 years.

    Q3.  What do you see as the most important next step in advancing our
    understanding of deflection approaches?

    A3. Testing and demonstrating both the kinetic impact (KI) and gravity
    tractor (t/GT) concepts. As mentioned above a slight modification of
    ESA's Don Quixote mission could fully validate both components of a
    deflection campaign in a single program for a total cost of between
    $500M and $1B dollars. In a cooperative program with ESA, NASA's share
    of this would be comparable to the cost of an average low-cost
    scientific mission.

    Q4.  What do you think would be the most appropriate next steps in
    addressing the governance issues discussed at the hearing?

    A4. Step 1 would be to assign responsibility to NASA for 1) analyzing
    and developing NEO impact warning concepts, and 2) for developing and
    testing NEO deflection technology.
        Search is important, without question. However someone now needs to
    be working through the complex issues of what we do when we discover a
    NEO which ``has our address'' on it. . . or, more likely appears to
    have our address on it. With the exception of flight testing the
    deflection concepts, these actions require very little money; the task
    is primarily to conceptually work through the complex issues involved.
        Step 2 would be to address the larger question of overall
    responsibility for handling this devastating but preventable natural
    hazard. This issue is particularly challenging in that unprecedented
    levels of destruction are at issue and in the process of eliminating
    the risk of an impact for everyone certain nations will of necessity
    have to accept a temporary increase in risk to their populations. Such
    a collective international decision will require considerable
    diplomatic efforts involving not only cost sharing, but also liability,
    indemnification, oversight and other sensitive considerations. While
    the technical aspects of warning and deflection will inform many of
    these considerations the primary challenge embedded here is national
    and international policy.
        In addressing this it would seem that no single Congressional
    committee has appropriate jurisdiction. Therefore at the outset the
    Congress and the Administration would benefit from the issue being
    considered in depth by an appropriate highly-regarded professional
    organization, such as the National Academies.

    Questions submitted by Representative Tom Feeney

    Q1.  NASA's NEO Report, delivered this March, provides several options
    for meeting the goal of achieving 90 percent detection, tracking and
    characterization of Potentially Hazardous Objects, and the report
    establishes a clear relationship between resources invested and the
    time needed to achieve 90 percent coverage. In essence the report shows
    that for an additional investment of approximately $536 million, we
    could buy-down a decade of time to complete the survey. In your view,
    is that additional investment necessary? Does the threat posed by PHOs
    compel faster completion of the survey?

    A1. This is an excellent public policy question, not a technical one. I
    believe that the following are considerations which should be taken
    into account in addressing the issue.

            1.  A growing segment of the general public is aware of the NEO
            threat. A smaller, but also growing segment of the public is
            aware that we have the technology today to not only warn us of
            a pending impact but also to prevent a devastating impact. Over
            the next decade, under any circumstances, there will be a
            number of what will be reported in the press as ``close
            calls.'' There will also likely be several, perhaps even
            hundreds, of NEOs that will appear to be threatening and will
            be reported (and misreported) by the public media. The issue,
            and its ``solution,'' will become widely known to the public.

            2.  A widely stated fact is that ``If we know about them, we
            can do something about it. The ones we need to worry about are
            the ones we don't know about.'' The public will come to know
            that the survey could be accelerated by 10 years at the cost of
            foregoing a single scientific satellite, or less (see comment
            below). Alternatively adding $500M to the NASA budget over 5-7
            years would suffice.

            3.  2008 is the 100th anniversary of the ``Tunguska Event.''
            There will be a great deal of publicity about this and many
            legitimate and not so legitimate presentations and discussions.

            4.  Every hurricane, earthquake and tsunami which creates great
            damage in the next decade will be another poster child for the
            possibility of a NEO impact, especially if one occurs in
            temporal proximity to a NEO ``near miss.''

            5.  From an ``objective'' perspective the NASA/JPL staff could
            compute the probability of an impact of various sizes occurring
            in the absence of the faster survey and compute the cost-
            effectiveness of the additional $536M of ``insurance.'' (In
            rough terms, using Apophis as an example, the cost of an impact
            is approximately $400B. If the probability of an Apophis impact
            (and its unfound cohorts) not being found is one in 1000 then
            the actuarial value of finding it in time to prevent the impact
            is $400M. Such an actuarial analysis could be performed).

        Note: Dr. J. Anthony Tyson, Director of the LSST, testified at the
    hearing that if NASA were to fund 15 percent of the LSST costs it would
    effectively have at its disposal, for $125M, a dedicated LSST and be
    able to meet the Congressional 140 meter goal within 12 years from LSST
    by 2026.

    Q2.  What are the most difficult types of NEOs to detect? Is there, for
    instance, a portion of the sky that won't be covered by ground-based
    facilities? Are there certain types of orbits that make it difficult to
    detect and track asteroids and comets?

    A2. There are two factors which are critical; size and type of orbit.
    Small NEOs can only be seen when they are very close to the Earth
    compared with larger NEOs. There are also many more small NEOs than
    large ones (e.g., 1,000 NEOs larger than one km in diameter vs. 40,000
    NEOs larger than 140 meters diameter, and 800,000 at 40 meters and
    larger.) and therefore the vast majority of unfound NEOs are at the
    smallest end of the spectrum of those which can do damage on the
    Earth's surface.
        The second factor is the orbit size. Those NEOs whose orbits are
    smaller than the Earth's, i.e., whose orbits lie primarily inside the
    Earth's orbit, spend most of their time with a ``look angle'' too close
    to the Sun and its glare to be seen by optical telescopes. They are
    typically seen for a month or two for several years in succession,
    followed by many years when they cannot be seen at all. These NEOs are
    classified as Atens. When an Aten is also small the two issues compound
    such that a 40-140 meter diameter object may be seen only once or twice
    in a decade. Obtaining an accurate orbit is therefore quite difficult
    for these objects.
        As pointed out in the NASA report, a space-based telescope placed
    in a Venus-like orbit would be able to look outward (i.e., away from
    the Sun) and both discover and track these Atens which are challenging
    to observe from the Earth's surface.
        Comets (long period comets) orbit the Sun in very large orbits
    which extend beyond the orbit of Jupiter. They are only detected when
    they approach the Sun within the orbit of Jupiter and begin to out-gas
    due to gradual heating. From detection to the time they cross the
    Earth's orbit is typically only several months. This is inadequate time
    to mount a deflection and they are generally not considered objects
    from which we can protect ourselves. Happily they are also one percent
    of the asteroid problem and are therefore (currently) disregarded.

    Q3.  Once the LSST and Pan-STARRS telescopes are operating, and surveys
    for PHOs that are 140 meters or larger has commenced, what is the
    business and public safety case for expanding the search to detect and
    track smaller PHOs--for instance, down to a size of 50 meters? What are
    the cost and schedule implications?

    A3. As regards ``the business case'' (the potential for ``mining''
    asteroids) essentially the only issue is the cost to get to the
    asteroid. This depends entirely on the specific orbit, with those in
    Earth-like orbits being the least costly to target. Even a 40 meter
    diameter asteroid weighs in at 100,000 metric tons; a great deal of
    potentially useful resource for development. Therefore since there are
    many more small asteroids than large the most promising targets for
    resource utilization will be found among this population.
        Public safety is at issue any time an asteroid impacting the Earth
    can cause significant damage at the surface. The Earth's atmosphere
    protects us from NEOs smaller than 30-40 meters. Those in the vicinity
    of 40-100 meters may not reach the surface but will explode with such
    energy in the lower atmosphere that they create devastation at the
    surface even without reaching it per se. At sizes larger than 100-150
    meters they reach the surface of the Earth substantially intact causing
    even greater damage and potentially tsunamis if they impact the ocean.
        It is clearly a policy judgment but I (representing the Association
    of Space Explorers) consider a Tunguska-like impact to be approximately
    the threshold size at which public demand would mandate a deflection
    effort (this assumes that the NEO is known in advance and projected to
    impact). Had the Tunguska asteroid (approximately 45 meters in
    diameter, exploding with five megatons of energy or 333 Hiroshima
    bombs) exploded over a city instead of the middle of a Siberian forest
    it would likely have killed everyone in the city. It therefore seems
    prudent, from a public safety consideration, to ultimately extend the
    search down to this (or some equivalent) threshold limit.
        What needs to be recognized is that in the process of reaching the
    goal of 90 percent of the population of NEOs 140 meters and larger we
    will also discover approximately 40-50 percent of the NEOs 50 meters
    and larger. Without any further investment in larger telescopes an
    additional two decades (i.e., 2040) of search (which will be done in
    any case in order to monitor the larger NEOs) will ultimately extend
    this figure to near 90 percent. If one chooses to reach the 90 percent
    discovery level for 50 meter objects earlier (say by 2030) then either
    larger ground based telescopes or a modest (1 meter) space telescope
    in Venus-like orbit would have to be employed. The life cycle cost of
    this would approximate $1B according to NASA's estimation in their NEO
    Report to Congress.

    Q4.  One deflection solution, suggested by NASA, is to detonate a
    nuclear device in the vicinity of a PHO. What are the advantages and
    disadvantages of using this approach? What circumstances would argue
    against using a nuclear device in lieu of alternative approaches?

    A4. The only advantage of using a nuclear device over a kinetic
    impactor (KI) is in those rare instances where the total impulse
    required to deflect the NEO at issue is greater than can be provided by
    the KI. Assuming adequate warning (i.e., 15-20 years) this threshold is
    reached at approximately a 400 meter diameter NEO. An object of this
    size is statistically encountered only once every 100,000 years. At the
    current time we have discovered about 40 percent of NEOs this size and
    the probability that any of these will impact Earth in the next 100
    years is zero. By completion of the new survey (140 meters) we will
    have discovered about 95 percent of the 400 meter NEOs. Assuming that
    none of them is about to strike the Earth (very highly likely) it is
    only the remaining five percent still unknown which would pose a threat
    necessitating the use of a nuclear device for deflection. The
    probability of one of these residual five percent striking Earth is
    once per 2,000,000 years.
        The other, also very unlikely circumstance in which a nuclear
    device would be required is if, in the next few decades we discover a
    NEO of almost any size which is predicted to impact within 5-10 years
    from discovery. Since the probability of the smallest objects of
    concern (therefore the most populous and most likely to impact) is once
    in 1,000 years, the probability of encountering one of these in the
    next 10 years is one in 10,000. This small number is further reduced by
    the fact that at the completion of the 140 meter survey we will have
    discovered only (say) 50 percent of the 50 meter objects and therefore
    there would be only a 50 percent chance that we would have discovered
    such an impactor before it hit.
        The bottom line is that non-nuclear means are able to handle 98-99
    percent of the current population of dangerous asteroids (those above
    the threshold mentioned above) and this will grow to well over 99.9
    percent within the next two decades as we discover most of the
    remaining NEOs which would require nuclear means.
        But why not (NASA asks) use nuclear if it will work? Because the
    entire issue of NEO deflection is ultimately a collective (i.e.,
    international) decision and the world has clearly and unequivocally
    stated in treaties and elsewhere that it wants to keep nuclear weapons
    out of space. Can the U.S. act unilaterally? Of course. Is this wise?
    Absolutely not. Where non-nuclear means are adequate to do the job
    there is no objective reason for considering nuclear explosives.
        From the technical perspective the use of a nuclear device will
    also be highly unpredictable. The potential for fragmenting the NEO
    will be extremely difficult to rule out given the very unlikely case
    that an actual flight demonstration on an asteroid will be available.
    Furthermore the total impulse imparted to the NEO will be highly
    uncertain (as will be that of the kinetic impactor) and unlike the
    kinetic impactor which is easily tested, this uncertainty will remain.
    In any circumstance both the kinetic impactor and the nuclear stand-off
    explosion (or any other impulsive deflection technique) will not
    provide the precise orbit change needed to insure that the NEO will not
    pass through a return keyhole after the primary deflection maneuver.
    Therefore a deflection campaign must of necessity include the weak but
    precise deflection capability of a gravity tractor (GT) or other
    precision deflection technique to ``trim'' or slightly adjust the
    primary deflection in the event that it is headed for a keyhole post-
    primary deflection.
        In summary; those circumstances requiring the strength of a nuclear
    deflection are extremely improbable (and will become much less probable
    over time) and, given international treaties and world opinion against
    nuclear explosives in space the sufficiency of non-nuclear means will
    be the option of choice.

    Questions submitted by Representative Dana Rohrabacher

    Q1.  With regard to NASA's Spaceguard program, what changes, if any, do
    you recommend to make the program more effective? In your view, is
    further legislation required from Congress to implement needed changes?

    A1. Reading the question in the narrow sense, i.e., the Spaceguard
    Survey per se, I would emphasize recommendation #1 in my written
    testimony that the Congress, whether through Authorization or
    Appropriations, should require that NASA comply with the law and both
    recommend and initiate a search program (and supporting budget) to meet
    the 140 meter goal. Whether it takes 15 years or 17 years is far less
    important than that a specific program be committed to and initiated.
        Reading the question in its broader sense, i.e., the Spaceguard
    Survey as the overall initiative to protect the Earth from asteroid
    impacts, I would call on the Congress to expand NASA's current limited
    activities to include 1) developing a recommended NEO impact warning
    concept, and 2) developing and testing NEO deflection technology.
    (These are contained as recommendations #3 & 4 in my written
    testimony.) Not only is it important that we move ahead regarding the
    issue of ``what do we do when we find one with our address on it?'' but
    by systematically thinking through the issues involved in warning and
    mitigation, the search program per se will begin to focus on the most
    critical information needed rather than simply meeting a somewhat
    abstract numerical quota.
        One further observation here; under any circumstance the discovery
    rate of NEOs will dramatically increase in the immediate future due to
    the introduction of Pan-STARRS and LSST into the search process. There
    is no doubt whatever that given the considerable expansion in the
    number of NEOs discovered we will find many that will appear to
    threaten impact with Earth. If, by way of illustration, the current
    discovery rate of NEOs that appears to threaten impact is one per year,
    then even without any further commitment by NASA, that rate of
    discovery of apparently threatening NEOs will rise to 30 or more per
    year over the next 5-7 years. This will, without question, get the
    attention of the press and the public. Therefore it is critical that
    specific action beyond the search program be underway to assure the
    public that their safety is being responsibly attended to.

    Q2.  How important do you consider characterization in the overall NEO
    issue priorities?

    A2. Let me emphasize immediately that I am in the minority in what I am
    about to say, even among my fellow NEO community peers. I believe that
    my minority position is justified, having arguably thought through the
    deflection issues more thoroughly than most of my compatriots.
        I believe that characterization of NEOs, in the classic sense of
    learning the specific technical characteristics of asteroids per se
    (thermal, structural, mineralogical, and other descriptive
    characteristics) is not a priority in regard to protecting Earth from
    impacts. With respect to classical scientific values it is very
    important; but protection of the Earth from impacts is a public safety
    issue, not a scientific one.
        The basis for this low priority is that the inherent performance of
    the kinetic impact deflection concept (and nuclear explosion as well)
    is highly uncertain and variable. The momentum imparted to a NEO by
    crashing into it is determined more by the energy and the variable
    nature of the impact geometry than by any knowledge that can be gained
    through classical characterization efforts. Each NEO is unique and
    likely non-homogeneous. The effect of an impact will vary depending on
    the slope of the surface on which it happens to impact as well as on
    the specific local structural characteristics. The rotation of the NEO,
    whether it is hit a glancing blow, and whether there happens to be
    buried ice or other volatiles at the specific impact site are also both
    unknowable and likely highly variable.
        Therefore the technical parameter beta (the ``momentum
    multiplier'') has a wide range, usually approximated today as ranging
    from two to 10 or more. This large uncertainty, even assuming heroic
    characterization efforts, will never be reduced to a reliably
    predictable single value. Therefore a kinetic impact or nuclear
    explosion will always produce a range of predicted deflection results,
    e.g., 3-20 Earth radii, or 2-15 Earth radii. It is this intrinsically
    uncertain nature of the impulsive deflection techniques which risks
    deflecting the NEO such that it will miss the Earth (good) but risk
    passing through a return keyhole (bad). For this reason it will always
    be necessary to have an observer spacecraft, with a transponder and
    precision deflection capability (e.g., gravity tractor), standing by in
    real time to both confirm the success of the primary deflection and
    execute a precise adjustment to the deflection to avoid a future
    keyhole passage and subsequent impact.
        Given that the primary deflection will always have a degree of
    uncertainty sufficient to risk passage through any of hundreds of
    return keyholes, a precision orbit adjustment capability will always be
    required. This statement will remain true regardless of any amount of
    money spent on NEO characterization, given the many variables of a
    kinetic impact or nuclear explosion having nothing to do with NEO
    characteristics. So why spend the money when the inherent uncertainties
    can (and must) be handled by the precision trim capability?
        Conversely, if one is (and we should be) interested in the
    potential for utilization of asteroidal resources at some future time,
    then characterization of NEOs is very important indeed. This is,
    however, classical science in its proper role and not public safety.

    Q3.  What capabilities are required for a comprehensive campaign?

    A3. A comprehensive deflection campaign (for a ``direct'' NEO impact
    threat) will consist of the following 5 steps;

            1)  The launch and rendezvous of a transponder equipped
            spacecraft (t/GT) with the NEO,

            2)  The determination (confirmation) of a pending impact based
            on the dramatically improved orbit determination,

            3)  The launch and impact of a kinetic impactor (KI),

            4)  The determination of the precise post-impact NEO orbit, and

            5)  A precise orbit adjustment (trim) maneuver if the NEO is
            determined to be headed toward a return keyhole (t/GT).

        Given that the primary deflection may place the NEO on a path
    toward a return keyhole, a precision deflection capability will always
    be necessary. Therefore since a gravity tractor (or other future
    precision deflection technology becomes available) will also have a
    transponder aboard the spacecraft for steps 1, 4, and 5 would logically
    be a single transponder/gravity tractor (t/GT) combination.
        If the threatening asteroid is being deflected not from a direct
    impact but rather from a keyhole (with subsequent impact), then only
    steps 1, 2, and 5 need be employed. An example of this situation is the
    current Apophis case where, if in 2013 it is determined that the NEO is
    indeed headed for the 7/6 keyhole in its 2029 close approach to Earth,
    a t/GT mission alone can be utilized to affect the deflection (i.e.,
    steps 1, 2 and 5 above.)

    Q4.  The need for a comprehensive potentially hazardous NEO program
    seems to require expertise of several agencies. How do you suggest
    coordination be handled?

    A4. The primary technical expertise required for a comprehensive NEO
    impact mitigation capability lies within NASA per se. The exception to
    this is the remote possibility of encountering a NEO threat which
    exceeds the capability of the kinetic impactor for primary deflection.
    If it is deemed prudent to prepare for this unlikely eventuality then
    NASA will need to coordinate with DOE regarding nuclear stand-off
    deflection capabilities and requirements. This coordination can be done
    in much the same manner as currently done when NASA utilizes nuclear
    materials (e.g., RTGs) or as was done in the recently canceled
    Prometheus program which utilized a nuclear reactor.

    Q5.  Describe some of the proposed mitigation techniques and their
    trade offs.

    A5. There are three techniques available with no new technological
    developments required prior to use. In all three cases there is
    significant engineering required. (Many neutral observers would
    challenge these statements for the nuclear stand-off option, however I
    will not challenge the advocates here.) These three divide into two
    types; the impulsive (virtually instantaneous action) techniques of
    kinetic impact (KI) and nuclear stand-off explosion, characterized by
    significant total impulse capability but with a highly unpredictable
    outcome, and the ``slow push'' technique (using NASA's term) of the
    gravity tractor, characterized by a modest total impulse capability but
    high precision and full controllability. Either of the impulsive
    techniques would necessarily be used in concert with the latter to
    insure a fully successful deflection.
        The nuclear option has the disadvantages of both political
    opposition, especially international, and technological uncertainties
    which can never (in all likelihood) be tested prior to potential use.
    The guidance and timing constraints to achieve a planned result in
    addition to the possible fragmentation of the NEO are all significant
    challenges which will persist until actual use is attempted. A further
    leap of faith is taking at their word the nuclear effects experts who
    claim that the behavior of a NEO exposed to a pulse of neutrons will
    behave as the computer models predict. On the positive side the total
    impulse available for altering the orbit of a NEO is potentially
    greater than any other option.
        The kinetic impact (KI) and gravity tractor (GT) technologies use
    available and proven technology, albeit in both cases engineering
    software needs to be developed and tested. Both techniques can, and
    should, be fully tested and demonstrated. This should be done in the
    near future to provide both official and public confidence prior to the
    time that a threatening NEO is discovered. The KI concept could also
    cause NEO fragmentation, but in this case it can be tested early and
    inform operational design to provide confidence in actual use. The GT
    concept is completely benign since it makes no contact with the NEO and
    can easily be tested and its performance validated in the immediate
    future.
        There have been other deflection concepts proposed but all, in one
    way or another, require advanced technology development, the resolution
    of key unknown factors, or pose less cost effective solutions than
    those currently available. All such techniques should be further
    investigated and analyzed to support decisions on future technology
    development and testing. None, however, should be considered to be
    currently ready for deployment as are the three recommended above.

    Q6.  What is your assessment of the need for a nuclear capability?

    A6. There is a very limited, near-term value in having a nuclear
    capability conceptually available for NEO deflection. The need is very
    limited, however, and a determination of the high cost and complexity
    of further development of this technique must be judiciously weighed
    against the very low probability of it being needed viz. non-nuclear
    techniques.
        Based on current analysis it appears that the KI technique can
    provide the total impulse to deflect any NEO up to approximately 400
    meters in diameter given 15-20 years of warning. Given that the
    statistical frequency of a 400 meter NEO impacting Earth is about once
    per 100,000 years the probability of needing to use nuclear deflection
    is approximately .05 percent over the next 50 years. (I use 50 years on
    the assumption that by that time more capable non-nuclear technologies
    will be developed.) Further reducing this probability is the fact that
    we have already discovered about 40 percent of the 400 meter NEOs and
    none has any possibility of impacting Earth in the next 100 years. The
    likelihood therefore drops to .03 percent based on the remaining 60
    percent of yet to be discovered 400 meter NEOs. However based on
    similar reasoning, by the completion of the new 140 meter search
    program in 15 years the completion rate for 400 meter NEOs will
    approximate 95 percent of the population reducing further the
    probability of needing to use nuclear technology to about .004 percent.
    Finally, for warning times exceeding 20 years or so any significant
    development costs can await such warning and still be ready for
    deployment if needed.
        The missing element in the above paragraph is the similarly very
    low probability that within the next 15 years a 400 meter or larger NEO
    will be discovered with an impact date within 20 years, i.e., an
    ``immediate'' impact. In this instance only the extant nuclear
    technology would be available for use. The probability of this
    situation arising can be approximated based on the statistical impact
    rate of 400 meter NEOs at once per 100,000 years. This is based on all
    of the 400 meter NEOs being unknown. If we assume that it will take
    approximately 20 years to discover ``all'' of the 400 meter NEOs then
    the probability a 400 meter NEO impacting within the next 20 years is
    one in 2,000 or .05 percent. However since we have already discovered
    40 percent of the 400 meter NEOs and will reach about 95 percent within
    the next 15 years, this probability is .03 percent now and will
    diminish to .004 percent within 15-20 years.
        The public policy question is then, what expense is justified in
    investing specifically in preparing nuclear technology for use in
    deflecting NEOs over the next 20 years with the probability of use
    being about one in 10,000? Beyond that timeframe adequate warning time
    will permit this investment if and when needed.
        My personal opinion is that this investment is not justified, other
    than perhaps some minor analytic studies.

    Q7.  Why, in your written testimony, do you state that the most
    important question you have been asked by the Committee is ``What
    governance structures need to be established to address potential NEO
    threats?''

    A7. From my work on this issue over the past six years it has become
    evident to me that the most challenging aspect of protecting the Earth
    from NEO impacts will be the decision-making process. Without
    elaboration, ``we can know something is coming at us, and we can have
    something to do about it, but unless we can make the decision to take
    action, we will still end up like the dinosaurs.'' Clearly this is an
    overly dramatic statement since the likelihood of being struck by a
    small NEO which might devastate a city-sized area is 1000s of times
    more likely than an extinction event. Nevertheless it clearly makes the
    point that warning and deflection are simple compared with the world
    making a coordinated decision to mount a NEO deflection campaign.
        The key to understanding this claim lies in the use of the word
    ``world.'' Without going into too much technical detail the need for a
    coordinated international decision arises from a combination of the
    orbital mechanics of NEO impact and the need for those nations at risk,
    and those nations placed at risk by the deflection itself, being
    involved in the decision. Such up front questions as who pays?, will
    there be indemnification for the deflecting entity?, will a deflection
    be mounted at all or should we ``take the hit'' are all examples of the
    need for international coordination.
        What has not yet been generally recognized, even within the ``NEO
    community'' is that in many (if not most) instances we will not be able
    to wait until after it is certain that a NEO will impact before
    launching a deflection campaign. The slow development of precise
    knowledge of the NEO's orbit over time, combined with the episodic
    nature of the collection of this knowledge assures that in many cases
    the quality of our knowledge at the latest possible time a deflection
    can be launched will require that we launch on probabilities of impact
    less than one. In certain instances where the threat is a NEO headed
    for a return keyhole prior to impact this launch decision may have to
    be made with the probability of impact being as low as one in 100 or
    even less.
        These observations translate on the ground into challenging
    international socio-political issues. When the probability of Earth
    impact is less than one, all we know is that there is a risk corridor
    extending completely across the Earth's surface, anywhere within which
    the NEO could hit, if it is indeed headed for impact. This generally
    narrow corridor (usually only 10s of kilometers wide) will cross many
    national boundaries thereby limiting which countries are at risk of an
    impact. However which specific country is destined for impact if a
    deflection is not completed is unknown, and will generally remain so
    until a transponder is brought into position at the NEO by the t/GT
    spacecraft, the first element of a deflection campaign. Therefore a
    decision to deflect will be of great interest to many but not all
    countries (the risk corridor may cross as few as two to or as many as
    10 or more countries). Will only these few countries called on to
    decide on a deflection and bear the cost? Or is the world community as
    a whole to debate the justification for sharing the cost? Will all, or
    a few, or none provide indemnification for the designated deflection
    entity? And by whom is the deflection to be performed and how will that
    nation, or consortium be chosen? Etc., etc. This is only a small
    sampling of the many difficult decisions that must be made in order to
    initiate a NEO deflection. Can such a decision be made unilaterally? Of
    course. However the implied liability and international furor should
    such an act be executed will likely inhibit such action. Even if, e.g.,
    the U.S. is threatened by such an impact and a unilateral action would
    seem justified, the consequence of such action would be to place other
    nations temporarily at risk in the process of deflecting the impact
    away from the planet.
        Clearly from this brief discussion it can be seen that the
    deflection (or mitigation) decision process will involve very difficult
    international political negotiations and trade-offs. The U.S. will have
    to be represented and indeed may well play a dominant role in such
    determinations. However the nature of the issues, while informed by
    technical realities, is primarily socio-political and it is doubtful
    that this responsibility would logically fall to NASA. Other logical
    candidates, in my personal order of priority would be Department of
    State, Department of Homeland Security, and Department of Defense.
        How this assignment of responsibility is to be determined is the
    public policy challenge to which I referred in my written testimony.
    Notwithstanding the challenging nature of the issues I believe the
    process of deciding this issue should start immediately given the
    protracted debate which will soon be initiated within the United
    Nations. This issue is currently on the UN Committee on Peaceful Uses
    of Outer Space (COPUOS) agenda for 2009 and the Association of Space
    Explorers is leading an international effort to draft a proposed UN
    Program for Asteroid Threat Mitigation which will be presented in the
    2009 COPUOS session. The U.S. needs to be prepared to not only
    participate but lead in these discussions.

    Q8.  You've made a number of recommendations regarding actions that
    should be taken by NASA and/or the Congress. Could you please estimate
    the cost of implementing these recommendations?

    A8. B612 Foundation has no credible capability to make such cost
    estimates. Nevertheless, with this being said I will address the
    question as best I can based on many years of working in the industry
    and on analogous program experience. I will refer, without elaboration,
    to the recommendations in my written testimony in addressing the
    question.

    Recommendation 1. ``. . .the Congress should again direct NASA in the
    clearest language possible to comply with the law and recommend a
    search program and supporting budget.''

        The cost of complying with this recommendation is specifically
    addressed in the NASA report to Congress. In addition, however, I
    strongly advise consideration of the oral and written testimony
    presented at the hearing by Dr. J. Anthony Tyson, Director of the LSST
    Project. Dr. Tyson pointed out that NASA could, in fact, and contrary
    to the NASA estimated cost in its report, obtain effectively a
    dedicated LSST for 15 percent of the life cycle cost of the telescope
    by contributing a total of $125M to the LSST Project.

    Recommendation 2. ``. . .NASA should produce a supplement to its Report
    to Congress based on new knowledge which has come to light since it
    began its analysis.''

        Given the baseline work already accomplished in the preparation and
    delivery of the NASA NEO Report to Congress and the relatively few but
    critical issues missed by NASA, it would seem that this supplement to
    the Report could be accomplished at 15-25 percent of the cost of the
    initial report. This is, however, purely a guess.

    Recommendation 3. ``NASA should assign someone in its NEO Program to
    the specific task of thinking through, analyzing and understanding the
    NEO deflection challenge.''

        The cost of implementing this recommendation is simply the cost of
    one or possibly two additional FTEs at JPL.

    Recommendation 4. ``NASA should validate a basic NEO deflection
    capability through the execution of a demonstration mission.''

        As described in my testimony a slight modification to ESA's
    proposed Don Quixote program could validate the fundamental elements of
    a full deflection campaign. Were NASA to undertake this full program on
    its own the program would involve the design, launch and execution of
    two relatively simple space missions in concert. The cost should
    therefore approximate the cost of two typical scientific missions or
    $600-800M.
        If, as should certainly be seriously considered, NASA were to cost
    share a cooperative program based on ESA's Don Quixote program with the
    Europeans, its cost share should drop to below $400M.

    Recommendation 5. ``. . .that the Congress expressly assign to NASA the
    technical development elements of protecting the Earth from NEO impacts
    as a public safety responsibility.''

        This recommendation's costs are largely covered by the combination
    of recommendations 3 & 4 above. The primary issue here is not any
    specific action but rather a clear and unequivocal assignment of
    responsibility. The development and/or testing of any new technology,
    in addition to that in recommendation 4, would be handled and cost
    justified on a case by case basis in future NASA budgets based on
    justified need.

    Recommendation 6. ``. . .that the Congress study the issue of overall
    governmental responsibility for protection of the Earth from NEO
    impacts, perhaps with the assistance of specialized policy entities,
    and ultimately hold public hearings to engage a wide perspective on the
    issue.''

        The cost of this recommendation would be the cost of a directed
    policy study (e.g., contracted to the National Academies by NASA) for
    perhaps $1-2M plus the cost of Congressional hearings on the issue.

    Q9.  Can you give an example or two of why NASA needs to think about
    deflection and not just about search and discovery?

    A9. I interpret this question to mean not ``why NASA?'' but rather
    ``why does deflection and not just search and discovery need to be
    thought about now?''
        The answer is that within the next 15 years, assuming that the
    Congressional 140 meter goal is responsibly addressed, we will be
    adding hundreds of thousands of NEOs to the existing database. Of this
    total approximately 150,000 of the NEOs discovered would, if they
    threaten an Earth impact, be equivalent to the Tunguska impact or
    larger and therefore be candidates for deflection. The remaining
    hundreds of thousands would be small enough that the atmosphere would
    prevent serious damage.
        Working by similarity to the existing NEO database, of these
    150,000 NEOs there will likely be 4500 or more (3.2 percent of the
    total database) with a non-zero (i.e., some actual) probability of
    Earth impact within the next 100 years. Of these 4500, if one or two
    percent are of comparable or greater concern than Apophis and 2004 VD17
    in the current database (both mentioned in the NASA Report) then there
    will be on the order of 45-90 NEOs of what might be called elevated
    concern by 2022. Of these NEOs it is highly likely that several, if not
    many, will have potential impact dates which will challenge our
    readiness to respond, i.e., by 2022 we will have dozens, and perhaps as
    many as 100 NEOs in our database which appear to be threatening, and
    many of them will have uncomfortably short response times.
        Knowing this to be the situation (and the numbers are clearly only
    approximate) from both statistics and similarity to our actual
    experience to date, it would be irresponsible to wait until the
    completion of the survey program and only then begin to develop a
    response plan. Were we to do that it would be immediately clear that
    our response capability would be delayed by perhaps 10 years or more.
    The consequence of such a delay would be that for 10s of potential
    impact threats, which we could have responded to if we had directed
    NASA to ``think about deflection and not just search and discovery''
    could not be prevented but only mitigated through evacuation, etc.
        Is it likely that any of these NEOs of elevated concern would
    actually impact? By definition, elevated concern means that they would
    have an unusually high probability of impact. If this elevated impact
    probability averaged one in 1,000 than in the example above the
    probability of any of them being an actual impact would be 4.5-9
    percent. This, as in most things NEO, is a public policy/public safety
    call. But given the relatively low cost of being prepared I believe
    that the public would be justifiably outraged if they were asked to
    accept a five percent chance of an impact for 10 years which could have
    been prevented by thinking ahead and allocating less than one half of
    one percent of the NASA budget to being prepared.

                                  Appendix 2:

                                  ----------

                       Additional Material for the Record

    NASA Rebuttal to remarks made by Mr. Schweickart during the November 8,
                   2007, hearing regarding Near Earth Objects

        The report on Near-Earth Objects NASA submitted to the Congress in
    March 2007 explicitly addressed a keyhole scenario on page 22, scenario
    A1. Figure 4 in this report shows that in any case where a small
    momentum change is required to deflect a threat, such as with a
    keyhole, the number of deflection options increases. The NASA report
    does not agree with the characterization that ``primary'' and then
    ``potentially secondary'' deflections are required. Instead it finds
    that, more generally, a series of missions will most likely always be
    planned to ensure that a particular threat does not impact the Earth
    with acceptable certainty. The study team also found that the options
    analyzed in the study would be a toolkit from which a deflection
    campaign could be designed, depending on the specifics of the threat
    scenario. The NASA report does not characterize post-deflection
    keyholes as a ``minefield.'' The report found that the likelihood of
    diverting a threatening object by a well-designed deflection mission
    into a keyhole to be very unlikely, and that even in this unlikely
    occurrence, a follow-on mission would by design be ready to complete
    the deflection. The report also does not indicate that this secondary
    deflection, if necessary, would necessarily be best performed by a slow
    push method.

                       Statement of The Planetary Society
                         in Support of Planetary Radar
                           at the Arecibo Observatory

                              PROTECTING THE EARTH

        Less than a century ago, a near-Earth object (NEO) slammed into
    Siberia, devastating 1,000 square miles. If it had struck just a few
    hours earlier or later in a populated area, it could have killed
    several hundred thousand people. NEOs pose a real and dangerous threat
    to Earth.
        In the past few years, we have been discovering, tracking, and
    characterizing the comets and asteroids that travel through our
    neighborhood of space. We have learned much--about near-misses, the
    probability of collisions, the diversity of asteroid and comet physical
    properties, and the effects of impacts in the past. We have even
    learned that one asteroid, named Apophis, will pass closer to Earth in
    22 years than our geosynchronous communications satellites, and its
    trajectory has a small probability of taking it on a collision course
    with Earth seven years after that.
        Radar tracking is the only way to precisely know the probability of
    impact, and the Arecibo telescope is the most powerful instrument for
    the job, 20 times more sensitive for NEO radar tracking than any other
    instrument in the world. Unfortunately, Arecibo is slated to be closed
    by the National Science Foundation in a misguided attempt to free up
    funding for new projects that do not yet exist.
        Arecibo is the largest radio-telescope in the world. It has been,
    and continues to be, an enormously productive scientific facility,
    covering a broad range of science studies. While its contributions to
    radio astronomy, ionospheric and atmospheric observations have proven
    valuable for the past several decades, it is its planetary radar
    capabilities that remain unique. Because of Arecibo's powerful one-
    million watt transmitter, and the large 1,000-foot aperture, the
    telescope is uniquely able to characterize potentially hazardous NEOs
    and determine the danger they pose. Radar signals from this facility
    are the only ones that can be regularly used for reaching and tracking
    NEOs that may be coming close to Earth.
        The cost of operating Arecibo is just a few million dollars per
    year. Isn't the safety of Earth worth that?
        In addition to tracking NEOs, Arecibo has returned other recent
    important results from planetary radar, including the best physical
    characterization of any potentially hazardous asteroid as large as a
    kilometer, ultra precise determinations of Mercury's spin state that
    reveal that planet to have a molten core, and the identification of
    several binary asteroids in the near-Earth population.
        Arecibo is caught in a bureaucratic argument. The Arecibo
    Observatory is a National Science Foundation (NSF) operation, but they
    consider the subject of NEOs and planetary radar to be in NASA's
    bailiwick. NASA supports ground-based astronomy, and supported the
    Arecibo radar for many years, but the agency now objects to picking up
    the funding of what is currently an NSF program.
        The House Science and Technology Committee has been the leading
    government advocate for understanding the nature and possible threat
    from objects (NEOs) that might impact the Earth. In the past, the
    Committee has had to direct NASA to provide increased support to this
    area. The Planetary Society has no position on whether this should be a
    NSF program or a NASA program; but, we strongly feel that it should be
    an American program with congressional support. We urge you to provide
    such support to keep the Arecibo planetary radar operating.
        The Planetary Society recently conducted a privately funded,
    international competition to design a mission to tag the asteroid
    Apophis, in case its Earth approach is close enough to require higher
    accuracy tracking. The competition attracted thirty-seven proposals and
    has generated much public interest.
        The cost of a tagging mission to Apophis would be at least $100
    million--and the only way to know if such a mission is necessary is to
    refine the current estimate of Apophis' orbit with the powerful radar
    tracking of a telescope like Arecibo. Avoiding one unnecessary tagging
    mission would more than pay back any investment of funds to keep
    Arecibo open. And if some object out there really is on a collision
    course with Earth and we don't have the means to track it properly, the
    price we would pay would be astronomical.
        Thank you for your consideration.