[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.
    
    
    

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