[House Hearing, 115 Congress]
[From the U.S. Government Publishing Office]




                      PLANETARY FLAGSHIP MISSIONS:
                   MARS ROVER 2020 AND EUROPA CLIPPER

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

                                HEARING

                               BEFORE THE

                         SUBCOMMITTEE ON SPACE

              COMMITTEE ON SCIENCE, SPACE, AND TECHNOLOGY
                        HOUSE OF REPRESENTATIVES

                     ONE HUNDRED FIFTEENTH CONGRESS

                             FIRST SESSION

                               __________

                             JULY 18, 2017

                               __________

                           Serial No. 115-22

                               __________

 Printed for the use of the Committee on Science, Space, and Technology



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

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              COMMITTEE ON SCIENCE, SPACE, AND TECHNOLOGY

                   HON. LAMAR S. SMITH, Texas, Chair
FRANK D. LUCAS, Oklahoma             EDDIE BERNICE JOHNSON, Texas
DANA ROHRABACHER, California         ZOE LOFGREN, California
MO BROOKS, Alabama                   DANIEL LIPINSKI, Illinois
RANDY HULTGREN, Illinois             SUZANNE BONAMICI, Oregon
BILL POSEY, Florida                  AMI BERA, California
THOMAS MASSIE, Kentucky              ELIZABETH H. ESTY, Connecticut
JIM BRIDENSTINE, Oklahoma            MARC A. VEASEY, Texas
RANDY K. WEBER, Texas                DONALD S. BEYER, JR., Virginia
STEPHEN KNIGHT, California           JACKY ROSEN, Nevada
BRIAN BABIN, Texas                   JERRY MCNERNEY, California
BARBARA COMSTOCK, Virginia           ED PERLMUTTER, Colorado
BARRY LOUDERMILK, Georgia            PAUL TONKO, New York
RALPH LEE ABRAHAM, Louisiana         BILL FOSTER, Illinois
DRAIN LaHOOD, Illinois               MARK TAKANO, California
DANIEL WEBSTER, Florida              COLLEEN HANABUSA, Hawaii
JIM BANKS, Indiana                   CHARLIE CRIST, Florida
ANDY BIGGS, Arizona
ROGER W. MARSHALL, Kansas
NEAL P. DUNN, Florida
CLAY HIGGINS, Louisiana
RALPH NORMAN, South Carolina
                                 ------                                

                         Subcommittee on Space

                     HON. BRIAN BABIN, Texas, Chair
DANA ROHRABACHER, California         AMI BERA, California, Ranking 
FRANK D. LUCAS, Oklahoma                 Member
MO BROOKS, Alabama                   ZOE LOFGREN, California
BILL POSEY, Florida                  DONALD S. BEYER, JR., Virginia
JIM BRIDENSTINE, Oklahoma            MARC A. VEASEY, Texas
STEPHEN KNIGHT, California           DANIEL LIPINSKI, Illinois
BARBARA COMSTOCK, Virginia           ED PERLMUTTER, Colorado
RALPH LEE ABRAHAM, Louisiana         CHARLIE CRIST, Florida
DANIEL WEBSTER, Florida              BILL FOSTER, Illinois
JIM BANKS, Indiana                   EDDIE BERNICE JOHNSON, Texas
ANDY BIGGS, Arizona
NEAL P. DUNN, Florida
CLAY HIGGINS, Louisiana
LAMAR S. SMITH, Texas

















                            C O N T E N T S

                             July 18, 2017

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

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

                           Opening Statements

Statement by Representative Brian Babin, Chairman, Subcommittee 
  on Space, Committee on Science, Space, and Technology, U.S. 
  House of Representatives.......................................     4
    Written Statement............................................     6

Statement by Representative Ami Bera, Ranking Member, 
  Subcommittee on Space, Committee on Science, Space, and 
  Technology, U.S. House of Representatives......................     8
    Written Statement............................................     9

Statement by Representative Eddie Bernice Johnson, Ranking 
  Member, Committee on Science, Space, and Technology, U.S. House 
  of Representatives.............................................    11
    Written Statement............................................    13

Statement by Representative Lamar S. Smith, Chairman, Committee 
  on Science, Space, and Technology, U.S. House of 
  Representatives................................................    14
    Written Statement............................................    15

                               Witnesses:

Dr. Jim Green, Planetary Science Division Director, Science 
  Mission Directorate, NASA
    Oral Statement...............................................    17
    Written Statement............................................    20

Dr. Kenneth Farley, Mars Rover 2020 Project Scientist; Professor 
  of Geochemistry, California Institute of Technology
    Oral Statement...............................................    25
    Written Statement............................................    27

Dr. Robert Pappalardo, Europa Clipper Project Scientist, Jet 
  Propulsion Laboratory, California Institute of Technology
    Oral Statement...............................................    30
    Written Statement............................................    32

Dr. Linda T. Elkins-Tanton, Director and Foundation Professor, 
  School of Earth and Space Exploration, Arizona State 
  University; Principal Investigator, NASA Psyche Mission
    Oral Statement...............................................    36
    Written Statement............................................    38

Dr. William B. McKinnon, Co-Chair, National Academy of Sciences, 
  Committee on Astrobiology and Planetary Science; Professor of 
  Earth and Planetary Sciences, Washington University in St. 
  Louis
    Oral Statement...............................................    43
    Written Statement............................................    45

Discussion.......................................................    58

             Appendix I: Answers to Post-Hearing Questions

Dr. Jim Green, Planetary Science Division Director, Science 
  Mission Directorate, NASA......................................    74

Dr. Kenneth Farley, Mars Rover 2020 Project Scientist; Professor 
  of Geochemistry, California Institute of Technology............    78

Dr. Robert Pappalardo, Europa Clipper Project Scientist, Jet 
  Propulsion Laboratory, California Institute of Technology......    79

Dr. Linda T. Elkins-Tanton, Director and Foundation Professor, 
  School of Earth and Space Exploration, Arizona State 
  University; Principal Investigator, NASA Psyche Mission........    80

            Appendix II: Additional Material for the Record

Responses submitted by NASA......................................    84
 
                      PLANETARY FLAGSHIP MISSIONS:
                   MARS ROVER 2020 AND EUROPA CLIPPER

                              ----------                              


                         TUESDAY, JULY 18, 2017

                  House of Representatives,
                             Subcommittee on Space,
               Committee on Science, Space, and Technology,
                                                   Washington, D.C.

    The Subcommittee met, pursuant to call, at 10:09 a.m., in 
Room 2318 of the Rayburn House Office Building, Hon. Brian 
Babin [Chairman of the Subcommittee] presiding.


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    Chairman Babin. The Subcommittee on Space will come to 
order.
    Without objection, the Chair is authorized to declare 
recesses of the Subcommittee at any time.
    And welcome to today's hearing titled ``Planetary Flagship 
Missions: Mars Rover 2020 and Europa Clipper.'' I recognize 
myself for five minutes for an opening statement.
    NASA's planetary science flagships are the crown jewels of 
our robotic exploration of the solar system. Viking, Voyager, 
Galileo, Cassini, Chandra, and Mars Science Laboratory are 
programs that have inspired generations of Americans. One need 
only visit a local elementary school to see the wonder in 
children's eyes as they learn about the great discoveries of 
these flagship missions. Mars Rover 2020 and the Europa Clipper 
will be no less amazing.
    Upholding such a legacy is not easy. From its original 
recommendation by the National Academies, through formulation 
and development, and ultimately launch and mission operations, 
there is much work to be done to ensure mission success, that 
the taxpayers' money is being appropriately spent, and that the 
national interest is met.
    Today's hearing serves an important oversight purpose. Our 
witnesses will provide important testimony on the Mars Rover 
2020 and the Europa Clipper, from both a programmatic and 
science perspective. The hearing will also provide an 
opportunity for Committee members to learn about the science 
that these missions will conduct and how it will benefit our 
nation.
    I have full faith that NASA and its hard working men and 
women will carry out its planetary science flagship missions 
successfully. That said, NASA is entering the most critical 
stage of the Mars Rover 2020 development and is undertaking the 
development of the Europa Clipper, and possibly a Europa 
Lander, at the same time.
    For Mars Rover 2020, the NASA Inspector General reported 
concerns regarding an overly optimistic schedule for Mars Rover 
2020 based largely on technology development challenges. I look 
forward to hearing from Dr. Green about these issues and how 
NASA is addressing them.
    A fundamental oversight question that needs to be addressed 
is how developing and operating these flagship missions at the 
same time, including a possible lander, will affect the 
Planetary Science Division and broader Science Mission 
Directorate portfolio. NASA must remain vigilant to protect 
against potential cost growth or mission creep that could 
impact other activities.
    The Consolidated Appropriations Act of 2017 funded and 
requires a Europa lander mission to complement the Clipper. The 
Act directed NASA to launch the Clipper in 2022 and a lander in 
2024.
    In the fiscal year 2018 President's budget, his request 
does not include funding for a Europa lander. NASA says that 
because the Planetary Science division already supports two 
other large strategic missions, Mars Rover 2020 and Europa 
Clipper, it cannot accommodate a Europa lander without 
significant impacts to other programs, and while a Europa 
lander is not included in the fiscal year 2018 budget request 
from the Administration, it has become an established concept 
for the future. NASA's Europa Lander Science Definition Team 
conducted a study on the topic in 2016 to evaluate landing on 
Europa and assess the science value and engineering design of a 
future lander mission. More recently, NASA released a community 
announcement to ask scientists what instruments would befit a 
Europa lander and NASA continues to work on lander design 
concepts.
    I strongly support NASA and its efforts with the Mars Rover 
2020 and Europa Clipper. I also believe there is great value in 
exploring the possibility of a Europa lander. However, it is 
critical that as Congress and NASA moves forward, we do our due 
diligence to assure not only flagship mission success, but also 
the success of the entire Planetary Science portfolio. I'd like 
to highlight the importance of sufficient research and analysis 
funding so that scientists can actually study the data derived 
from these missions.
    I want to thank the witnesses for being here today and I 
look forward to your testimonies.
    [The prepared statement of Mr. Babin follows:]
    
    
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    Chairman Babin. And now I recognize the Ranking Member, the 
gentleman from California, for an opening statement. Mr. Bera.
    Mr. Bera. Thank you, Mr. Chairman. And I had to look back 
there. I see my old friend, our former colleague, Congressman 
Matt Salmon, in the audience. We miss you, Matt. Thanks for 
being here.
    Chairman Babin. I just saw him too.
    Mr. Bera. You know, thank you for holding this hearing, 
``Planetary Flagship Missions: Mars Rover 2020 and Europa 
Clipper.'' I think for both of us, we've talked about this, and 
for many of us of a generation that grew up in the space race, 
just the imagination, thinking about, you know, whether it was 
going to the moon or beyond, the Apollo missions to Skylab to 
Apollo-Soyuz to the space shuttle programs captured our 
imagination, and to a new generation of our kids and grandkids, 
they continue to capture our imagination of going beyond.
    We live in a time where we've sent spacecraft to explore 
the moon, all eight planets, Pluto, several asteroids and 
comets. And just last week, the NASA Juno spacecraft provided 
us an amazing view of Jupiter's mysterious Great Red Spot. So, 
you know, these missions are incredibly important because it 
allows us to know that we're part of something bigger, and now 
we've got Voyager One that is traveling through interstellar 
space. The reach of our scientific exploration is truly 
inspiring.
    And to maximize the scientific return on investment for 
planetary exploration, NASA develops both large and small 
missions to visit a range of destinations throughout our solar 
system. We're here to talk about large flagship missions like 
Mars 2020 and Europa Clipper missions because they play an 
important role in using complex instruments to help us 
understand the challenge of exploring hard-to-reach locations 
but we spend less time talking about the smaller missions, like 
the Psyche mission that's represented on our panel. These are 
launched more frequently in response to new discoveries. These 
missions also provide opportunities for students to engage in 
mission design, development, and operation. So the mixture of 
both the large planetary missions but also the small is an 
intentional mix and it provides significant value and has 
through the history of NASA's planetary science program.
    We also know that NASA's planetary missions have greatly 
advanced our understanding of the solar system and its 
potential to harbor life beyond Earth. Now, imagine if we were 
to identify life beyond Earth. That would be disruptive for all 
of humanity in a way of answering that seminal question, are we 
alone? And, you know, life may not be in the form of human 
life. It may be microbiotic life, et cetera, but even that 
discovery would be dramatic and change how we viewed ourselves 
in the context of our universe.
    So I look forward to learning more about the role of large 
and small planetary missions and the importance of supporting 
this balanced mission size and, you know, I want to acknowledge 
the panel here. I also want to acknowledge the long-term 
commitments that we make as a body to fund this discovery, and 
it's incredibly important to us.
    So with that, I'll yield back
    [The prepared statement of Mr. Bera follows:]
    
    
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    Chairman Babin. Thank you, Mr. Bera.
    I now recognize the Ranking Member of the full Committee 
for a statement. Ms. Johnson.
    Ms. Johnson. Thank you very much, Mr. Chairman.
    Before I get into my formal statement, I just want to take 
a moment to say that this Friday marks 48 years of Apollo 11 
moon landing, and as we look forward to inspiring our younger 
generation, whom I know many are sitting right out there, for 
the exciting future missions to Mars, Europa and asteroids, 
just remember that just 48 years ago this Friday, we had a 
previous generation of young people. America has an impressive 
legacy of accomplishment in both robotic and human space 
exploration, and I hope that we can continue to build on it. I 
hope that your minds will be just as inspired for our future as 
we have seen for our past. Now for my formal statement.
    Let me welcome all of our witnesses. I look forward to your 
testimony.
    Mr. Chairman, I thank you for holding this hearing on 
planetary flagship missions. Through our investigations in 
NASA's planetary science program, NASA has been able to explore 
every planet in the solar system, as well as Pluto; 
continuously operate missions to Mars for the past two decades; 
and discover an expanding realm of potentially habitable bodies 
both within and beyond the solar system. With each discovery, 
NASA is advancing knowledge, pushing technological boundaries, 
and inspiring future generations to pursue science and 
technology education and careers. That is why I have often 
referred to NASA's science program as one of America's crown 
jewels.
    And we will hear this morning even more exciting planetary 
science missions lie ahead. As I speak, NASA is developing two 
planetary flagship missions. The Mars 2020 Rover will assess 
the habitability of Mars and look for signs of past life. In 
addition, the Europa Clipper mission will investigate the ice 
shell of Jupiter's moon Europa and its underlying ocean, 
helping scientists to assess whether it can support life. 
These, like previous flagships, are very challenging missions. 
Mars 2020 will drill, collect, and cache samples of Martian 
rocks and soils, and Europa Clipper must withstand the intense 
radiation environment of Jupiter. Fortunately, NASA has decades 
of experience with flagship missions to draw on.
    With that in mind, I hope our witnesses can discuss the 
lessons learned from previous flagships and how we are using 
that knowledge in developing the Mars 2020 and Europa Clipper 
missions.
    Mr. Chairman, a discussion of flagship missions would be 
incomplete without mentioning the importance of balance in 
mission sizes, a critical element of a robust portfolio for 
both the National Academies and NASA Authorization Acts have 
repeatedly emphasized.
    To that end, I am pleased that this morning's discussion 
will also include smaller, Discovery-class missions, and their 
role in maintaining a productive and balanced planetary science 
program. Looking ahead, opportunities for new and exciting 
planetary science missions abound. Maintaining balance will 
take discipline among NASA, the scientific community, and 
Congress.
    Before I close, I want to take a moment to thank the 
talented, dedicated and committed workforce of NASA and its 
university, industry, and international partners. Our Nation's 
inspiring achievements in planetary science would not be 
possible without all of you.
    I thank you, Mr. Chairman, and yield back.
    [The prepared statement of Ms. Johnson follows:]
    
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    Chairman Babin. Thank you, Ms. Johnson.
    I now recognize our Chairman of our full Committee, Mr. 
Smith from Texas.
    Chairman Smith. Thank you, Mr. Chairman.
     The exploration of our solar system captures Americans' 
interests, inspires us to pursue extraordinary goals, and keeps 
us on the forefront of scientific achievement.
    Planetary missions teach us about how our solar system 
works and provide clues about how it was formed. They discover 
the locations of minerals and potential water sources on 
asteroids, comets, moons, and planets that could be used on 
future human missions or, in the case of minerals, extracted 
for use here on Earth.
    Planetary science also helps address a fundamental question 
of science: Is there life elsewhere in the universe? Within our 
own solar system, scientists have found strong evidence that 
other planetary systems could in fact host life.
    Europa, one of Jupiter's many moons, may have the necessary 
ingredients for life: water and energy. Its ocean lies beneath 
an icy surface and may be two times the volume of all Earth's 
oceans. Tidal forces drive active geological processes within 
Europa's ocean interior and provide energy. Scientists see 
similar activity in hydrothermal vents on Earth's ocean floor.
    The Europa Clipper mission, a flagship mission recommended 
by the National Academy of Sciences, will be an important 
mission to address the scientific question of whether there is 
life elsewhere in the universe. It will advance our 
understanding of planetary science as it explores the 
characteristics of Europa's oceans, ice surface, and other 
geological activity.
    Congress directed NASA to work on a Europa lander to 
complement the Europa Clipper. NASA's Europa Lander Science 
Definition Team conducted a study on the topic in 2016. The 
study found that the mission could analyze the biological 
potential of Europa's ocean by directly examining both Europa's 
surface and sub-surface. This is a very exciting concept that 
warrants NASA's continued efforts.
    Closer to Earth, Mars Rover 2020 will also study the 
habitability of Mars. It builds upon the discoveries from the 
Mars Curiosity rover and the two Mars Exploration rovers, 
Spirit and Opportunity. The mission not only seeks signs of 
habitable conditions in Mars' past, but also searches for signs 
of past microbial life itself. It will also test new technology 
that could benefit future robotic and human exploration of 
Mars. One of its instruments, MOXIE, will test a method for 
producing oxygen from the Martian atmosphere. Oxygen production 
on Mars will be critical for future human missions.
    I appreciate NASA's planetary science exploration efforts 
and the Trump Administration's support of American leadership 
in space. Other than national security agencies, NASA received 
the most favorable budget request from the Trump 
Administration. As a result, we can look forward to NASA 
undertaking a bold and ambitious agenda.
    I thank our witnesses and look forward to their testimony, 
and I'll yield back, Mr. Chairman.
    [The prepared statement of Mr. Smith follows:]
    
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    Chairman Babin. Thank you, Mr. Chairman.
    Now let me introduce our witnesses. We have a distinguished 
panel this morning.
    Our first witness today is Dr. Jim Green, the Director of 
the Planetary Science Division of the Science Mission 
Directorate at NASA. Welcome. Dr. Green has served as the Chief 
of the Space Science Data Operations Office at Goddard Space 
Center as well as the Co-Investigator and Deputy Project 
Scientist on the IMAGE mission. He received his Ph.D. in space 
physics from the University of Iowa. Welcome.
    Our second witness today is Dr. Ken Farley, the Mars Rover 
2020 Project Scientist. He is also a Professor of Geochemistry 
at the California Institute of Technology. He received his 
bachelor of science in chemistry from Yale and a doctorate in 
earth science from the Scripps Institution of Oceanography from 
the University of California in San Diego. Welcome.
    Our third witness today is Dr. Robert Pappalardo, the 
Europa Clipper Project Scientist at JPL at the California 
Institute of Technology. Dr. Pappalardo received his bachelor 
of arts in geological sciences from Cornell University as well 
as Ph.D. in geology from Arizona State University. Maybe that's 
why we see Representative Matt Salmon back there.
    Dr. Linda T. Elkins-Tanton, our fourth witness today, 
Director and Foundation Professor at the School of Earth and 
Space Exploration at Arizona State University. She is also the 
Principal Investigator for the NASA Psyche Mission. She 
received her bachelor's of science and her master's of science 
as well as her Ph.D. from MIT.
    Our fifth witness today is Dr. William B. McKinnon. He is 
Co-Chair of National Academy of Sciences' Committee on 
Astrobiology and Planetary Science. He is also a Professor of 
Earth and Planetary Sciences at Washington University in St. 
Louis. He received his bachelor of science degree in Earth and 
planetary sciences from MIT and his Ph.D. in planetary science 
and geophysics from Cal Tech.
    I would like to now recognize Dr. Green for five minutes to 
present his testimony.

                  TESTIMONY OF DR. JIM GREEN,

              PLANETARY SCIENCE DIVISION DIRECTOR,

               SCIENCE MISSION DIRECTORATE, NASA

    Dr. Green. Chairman Babin and the Members of the Committee, 
thank you so very much for giving us the opportunity to come 
and talk about certainly my favorite subject: planetary 
science. In my opening statement, I'd like to explain how 
missions like Mars 2020 and the Europa Clipper fit into an 
overall planetary exploration portfolio.
    [Chart]
    In my first chart, as you see, this is an overview of the 
current planetary missions. They're in a variety of 
formulation, implementation and currently operating missions 
that we have.
    This is a tremendously exciting time in planetary science. 
All our operating missions are making revolutionary discoveries 
and all are rewriting the textbooks.
    For instance, just two years ago, we had a fabulous fly-by 
of the New Horizon spacecraft through the Pluto system. With 
that mission, the United States becomes the first and only 
Nation to reach every major body in the solar system from 
Mercury to Pluto. Dr. Bill McKinnon on the panel is a New 
Horizons Co-Investigator.
    Today, NASA has numerous missions exploring and operating 
through the solar system such as the lunar reconnaissance 
orbiter, which is bringing us back to the moon and making 
exciting discoveries.
    The indomitable Mars Curiosity and Opportunity rovers along 
with our orbiters at Mars continue to make almost daily new 
discoveries about the red planet. For example, from our Maven 
mission, it has revealed that solar wind interactions with the 
upper atmosphere of Mars over time has literally stripped away 
most of that atmosphere, transforming Mars from what we believe 
was once a planet that could have supported life in its distant 
past to now a frigid, arid world.
    Adding to our Mars missions, Insight lander will be 
launched in May 2018 and land in November 2018. Insight is 
designed to study the interior of Mars along with understanding 
its present-day level of global seismic activity.
    In 2020, a new Mars rover will be launched carrying seven 
state-of-the-art instruments to conduct advanced geological 
research and search for signs of ancient Mars life. For the 
very first time, we will create high-grade rock core samples 
for potential return to Earth for further analysis. I look 
forward to Dr. Farley's testimony, which will provide 
additional information on that mission.
    Between Mars and Jupiter is a major asteroid belt where 
NASA's Dawn mission is currently studying the dwarf planet 
Ceres and finding evidence of past cryovolcanism.
    This year, NASA selected two discovery missions, Lucy and 
Psyche, which will respectively visit six Jupiter mysterious 
Trojan asteroids and study a unique metal asteroid that may 
actually be an exposed planetary core called Psyche. Dr. Linda 
Elkins-Tanton is here today to tell much more about the Psyche 
mission.
    NASA's robotic rendezvous and sample return mission that 
visits the Bennu asteroid is called OSIRIS-Rex. It will get a 
gravity assist by Earth in September and it will reach that 
potentially hazardous asteroid in August of next year. 
Examinations of objects like Bennu will allow our scientists to 
investigate how planets formed and how materials like water and 
organics actually were delivered in early impacts in addition 
to looking at the effects of potential planetary defense.
    In our outer solar system, Jupiter's mission Juno, which 
got into polar orbit our very first time in polar orbit at 
Jupiter last July. Since then Juno has been observing the cloud 
tops and into the interior of the planet, finding in the 
northern and southern polar regions that that planet is 
maintaining huge nearly Earth-size cyclones.
    After 13 years of orbiting Saturn, our Cassini spacecraft 
is making a daring dive between the planet's atmosphere and the 
first ring, and it will lead to plunging that spacecraft into 
Saturn on September 15 as it runs out of fuel. Cassini has 
given us a powerful insight into the planet's internal 
structure, atmosphere and rings in addition to unbelievable 
views of Titan and Enceladus.
    And if I may go on and summarize, finally, NASA recognizes 
there is still much to learn. With your support, we will 
continue to tackle solar system exploration goals identified as 
top priorities by the scientific community and delineated in 
the National Academies' Planetary Decadal.
    Again, thank you so much for the opportunity to testify 
today and I look forward to responding to your questions.
    [The prepared statement of Dr. Green follows:]
    
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    Chairman Babin. Thank you, Dr. Green.
    I now recognize Dr. Farley for five minutes to present your 
testimony.

                TESTIMONY OF DR. KENNETH FARLEY,

               MARS ROVER 2020 PROJECT SCIENTIST;

                   PROFESSOR OF GEOCHEMISTRY,

               CALIFORNIA INSTITUTE OF TECHNOLOGY

    Dr. Farley. Thank you for the opportunity to testify today 
on the Mars 2020 mission.
    Mars 2020 will seek evidence of past life in a fossil 
Earth-like environment that existed in the first billion years 
after the dawn of the solar system. This flagship mission will 
engage many hundreds of scientists and the American public in a 
very challenging journey through one of the most intriguing 
landscapes in the solar system and some of the most profound 
scientific questions of our time.
    Today Mars is too cold, too dry, and too exposed to harmful 
radiation to plausibly nurture life on its surface. However, 
more than two decades of sustained and strategic NASA-led 
exploration have shown that the red planet was once very 
different. Imagery from the Mars Odyssey and Mars 
Reconnaissance Orbiters reveals that prior to about 3.6 billion 
years ago, Mars had rivers, lakes, and possibly a vast northern 
ocean. Sophisticated analyses made on the planet's surface, 
most notably by the Spirit and Curiosity rovers, have richly 
documented ancient environments with all conditions believed 
necessary to sustain life. In that same early time period, 
conditions here on Earth were broadly similar, and life had 
already originated, evolved, and spread across the surface. 
However, unlike Earth, with its active erosion and plate 
tectonics, the geologic record of ancient Mars is exquisitely 
preserved for study, allowing us to seek answers to grand 
questions including how early climate and habitability evolve 
on rocky planets, the nature of prebiotic environments that 
might ultimately spawn life, and whether life is unique to 
Earth. Seeking the signs of life in an ancient habitable 
environment is the central goal of the Mars 2020 mission.
    Thanks to a wealth of images from the Mars Reconnaissance 
Orbiter, the science community has narrowed the possible Mars 
2020 landing sites down to three very different settings that 
on Earth are both habitable and inhabited: an ancient river and 
lake system, a fossil hot spring similar to those at 
Yellowstone National Park, and a setting where warm water once 
circulated through shallow subsurface rocks. Once on Mars, the 
rover will use its on-board instruments to investigate the 
local geology, to characterize the habitable environments the 
rover traverses, and to look for evidence of ancient life. 
Using Earth as a guide, we expect that any Martian life 
existing at that time was primitive, consisting only of 
microbes. Truly definitive discovery of microbial biosignatures 
by instruments on board the rover is unlikely, and can best be 
undertaken using the full arsenal of terrestrial laboratories. 
For this reason the Mars 2020 rover will prepare a complete 
suite of samples for possible return to Earth by a future 
mission.
    Mars 2020 starts with the designs of the remarkably 
successful Mars Science Laboratory (MSL) and the Curiosity 
rover. To this platform a suite of very capable new science 
instruments is being added to explore the structure, chemistry, 
and mineralogy of the surface all the way from the regional 
scale down to the microscopic scale. In addition, the mission 
is developing advanced new capabilities for landing in rugged 
terrain, for autonomous navigation and science observation, and 
for robotic coring and caching of samples. These are critical 
steps towards unleashing the full capabilities of robotic solar 
system investigation.
    The mission will also test new technologies beneficial to 
future human Mars exploration, most notably a device to 
demonstrate conversion of carbon dioxide in the Martian 
atmosphere into oxygen for use as a component of rocket 
propellant. The mission is currently in the implementation 
phase (Phase C) with a substantial amount of hardware already 
completed. Launch will occur in the summer of 2020, with 
arrival on Mars on February 18, 2021. The rover will be landed 
using the spectacular sky-crane system pioneered by MSL, and 
will explore the Martian surface for at least two years. In 
that period the rover will core and cache at least twenty rock 
samples, each about the size and shape of a piece of chalkboard 
chalk. These will be thoroughly documented and placed on the 
surface, accessible to retrieval by a future mission or even by 
human explorers. By collecting and caching a diverse suite of 
high-science-value rock samples, Mars 2020 fulfills the highest 
priority objectives of the Mars and planetary science 
communities as described in the most recent Planetary Science 
Decadal Survey.
    Mars 2020 will investigate a planet known with detail 
sufficient to compellingly address, for the first time, well-
posed and profound scientific questions that would forever 
elude answers from Earth-bound study. Going well beyond 
observations on the Martian surface, return of the cache to 
terrestrial laboratories would provide future generations of 
scientists across many disciplines access to samples that would 
transform our understanding of Mars, the solar system, and 
life. There is still an enormous amount to learn about Mars, 
and the deeper we penetrate, the richer the scientific tapestry 
becomes. Mars 2020 makes the next big step in this decades-long 
journey, and provides new focus and foundation for human 
exploration of Mars. It's an honor and a privilege for me to 
play a part in such a grand and ambitious undertaking.
    I look forward to your questions.
    [The prepared statement of Dr. Farley follows:]
    
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    Chairman Babin. Thank you, Dr. Farley.
    I now recognize Dr. Pappalardo for five minutes to present 
your testimony.

              TESTIMONY OF DR. ROBERT PAPPALARDO,

               EUROPA CLIPPER PROJECT SCIENTIST,

                   JET PROPULSION LABORATORY,

               CALIFORNIA INSTITUTE OF TECHNOLOGY

    Dr. Pappalardo. Chairman Smith, Chairman Babin, Ranking 
Member Bera and other Members of the Committee, I'm delighted 
to appear before you to describe recent progress in NASA's 
Europa Clipper mission.
    The ice-covered world Europa--moon of Jupiter similar in 
size to Earth's moon--shows a landscape of cracks, ridges, and 
jumbled, chaotic terrains indicative of a tumultuous past. The 
Galileo spacecraft, which orbited Jupiter beginning in the late 
1990s, provided images, compositional information, and gravity 
and magnetic data that point to a remarkable conclusion: Europa 
likely has a global ocean of liquid water beneath its icy 
carapace, maintained by tidal flexing and heating. From what we 
know of the tenacity of life, Europa could be one of the best 
places in the solar system to search for life beyond Earth.
    For these reasons, future detailed investigation of Europa 
is one of the top priorities for planetary exploration, as 
expressed in the National Research Council's 2011 Planetary 
Science Decadal Survey. The Europa Clipper mission responds 
directly to the Decadal Survey in its top-level goal: explore 
Europa to investigate its habitability, and in its science 
objectives to understand Europa's ice shell and ocean, 
composition, geology, and recent or current activity. The last 
of these categories includes the possibility that Europa may 
have active plumes that spew water vapor into space, and which 
could directly reveal Europa's internal composition and 
suitability for life. This tantalizing evidence for plumes is 
provided by the Hubble Space Telescope, searching at the 
extreme of its detection limits.
    In the tradition of the 19th century trading ships for 
which this mission was recently named, the Europa Clipper will 
sail past the Jovian moon at a rapid clip as frequently as 
every two weeks. providing many opportunities to investigate 
Europa from as close as 16 miles above the surface. During each 
flyby, the spacecraft will spend just a short time within the 
challenging radiation environment near Europa. The prime 
mission plan includes 40 to 45 flybys of Europa from Jupiter 
orbit, during which the spacecraft will interrogate the moon in 
unprecedented detail. This will include imaging to understand 
its geological history; compositional analyses including direct 
sampling of materials knocked off the surface; ice-penetrating 
radar to examine the 3D structure of its icy shell; and 
gravity, magnetic, and plasma measurements to understand its 
hidden interior and interactions with the Jupiter environment. 
The mission can also lay the foundation for future exploration 
of Europa, providing critical global context and scouting 
potential landing sites for a potential future landed mission.
    As its Project Scientist, I represent the science and 
scientific integrity of the Europa Clipper mission, ensuring it 
will address the top-level goal and objectives. I first 
testified before this Committee two years ago, just after NASA 
had competitively selected nine science instruments for the 
mission, and had given the green light to begin Phase A, known 
as mission formulation. In February of this year, NASA 
completed its second major milestone review, so today we're in 
Phase B, refining details of how the instruments will achieve 
the mission's science, and developing preliminary yet detailed 
design plans for the spacecraft and its subsystems, including 
the science instruments.
    Progress on the instrument suite has been outstanding. 
Instrument concepts have been reviewed; designs have matured; 
subsystem vendors are being selected; prototype parts are being 
built; detectors are being tested; and additional tests are 
being conducted to ensure robustness against the harsh 
radiation environment in Europa's vicinity.
    Beginning this fall and into next spring, each spacecraft 
subsystem and each instrument will undergo a preliminary design 
review to assure that the defined science can be achieved by 
the instruments and spacecraft in combination. These Phase B 
reviews are in preparation for the mission to proceed to Phase 
C around October 2018. It's also at this key decision point 
that NASA would make a final commitment as to a launch 
readiness date and baseline mission cost. Then during Phase C, 
flight hardware would be built.
    The members of the mission's science team are working 
cooperatively together to define the synergistic science which 
I see as this mission's hallmark. No one instrument can 
definitively affirm the ocean's existence or tell us 
convincingly of Europa's composition. Instead, each instrument 
technique provides a piece of the puzzle, and from the combined 
science data, Europa scientists will mature a complete picture 
of how Europa works as a complex system from its submerged 
rocky core to its ocean to the capping ice shell and surface, 
to its thin atmosphere, and the surrounding environment of 
Jovian space.
    The clipper ships of the late 19th century were an 
expression of speed and grace in the golden age of sail. We're 
now in a golden age of solar system discovery, and the Europa 
Clipper mission will return to us untold scientific riches.
    Thank you, and I look forward to your questions.
    [The prepared statement of Dr. Pappalardo follows:]
    
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    Chairman Babin. Thank you, Dr. Pappalardo.
    I now recognize Dr. Elkins-Tanton for five minutes to 
present her testimony.

            TESTIMONY OF DR. LINDA T. ELKINS-TANTON,

               DIRECTOR AND FOUNDATION PROFESSOR,

             SCHOOL OF EARTH AND SPACE EXPLORATION,

                   ARIZONA STATE UNIVERSITY;

          PRINCIPAL INVESTIGATOR, NASA PSYCHE MISSION

    Dr. Elkins-Tanton. Chairman Babin, Chairman Smith, Ranking 
Member Bera, and the Members of the Committee, thank you so 
much for the opportunity to speak today. Today I'll be 
testifying in my personal capacity.
    Any discussion of NASA's planetary science program would be 
incomplete without also talking about the balance between 
flagships and smaller planetary missions, and so today I'm 
going to talk about three things. I'm going to talk about the 
newly selected Psyche mission, I'm going to talk about 
portfolio balance, and I'm going to talk about our inevitable 
space future.
    I am the Principal Investigator of the Psyche mission, 
which in January was selected as the 14th in the NASA's 
Discovery program. The spacecraft is scheduled to launch in 
August of 2022 to rendezvous with the asteroid Psyche in 
January of 2026, and to orbit Psyche for 22 months. Psyche is a 
metal world with a diameter about the same as the width of 
Massachusetts and with a surface area larger than the area of 
Texas. Humankind has explored rocky worlds and we have explored 
icy worlds and we have explored worlds covered with gas but we 
have never before explored a metal world. This is a first.
    We think that Psyche is the core of a small early-formed 
planet that was bombarded in the early solar system and had its 
rocky exterior knocked off so that only its metal core remains 
showing today. Computer models of planetary formation indicate 
that this is rare, and indeed, Psyche is the only large, round 
metal object in our solar system, so it's not just unique, it's 
improbable.
    The science we hope to achieve in the mission is first to 
determine whether indeed Psyche is a core, or if it is some 
previously undiscovered kind of material. We'll be comparing 
what we learn at Psyche to models of the Earth's core to better 
understand that unreachable part of our own planet. And for the 
first time, we'll be investigating the morphology of a metal 
body. What do craters into metal look like? Could Psyche have 
glittering cliffs of metal and green pyroxene crystals? We 
don't know yet. No one knows yet. At Psyche, we will also take 
the first steps toward our space resource future because we're 
pretty confident that Psyche almost entirely consists of iron, 
nickel, copper, and a variety of trace metals.
    Now, I strongly support the Planetary Decadal Survey's 
conclusion about the necessity for having a balanced mission 
portfolio combining small and mid-sized missions on a regular 
tempo with flagships. Tempo is critical. Tempo maintains our 
workforce and it also saves our institutional memory, but each 
size of mission comes with its own challenges and its own its 
own advantages. For smaller missions like Psyche, usually 
keeping costs down and keeping risk down means that we're going 
to use trusted high-heritage components whereas flagship 
missions give us the opportunity for innovation and new 
technology development, and we need both of those things. We 
need our trusted technology today and we need new technology 
for the future.
    Flagship missions can also engage a broader swath of the 
community through competed calls for instruments. These calls 
can bring new groups onto missions that would otherwise not be 
involved but then the project scientist has the challenge of 
organizing and uniting otherwise disconnected sub-teams. It's 
an interesting challenge. In fact, all lead scientists have to 
build, inspire and lead large interdisciplinary teams, and 
normally engineers and scientists are not taught these skills, 
so we are trying to change that at ASU now.
    Exploration is a human imperative. It is stamped on our 
DNA, and space is the future of exploration for humankind. 
Every time we do this most extreme of technological miracles 
and we send a rocket off of our Earth to make discoveries in 
space, we encourage people all around the world to make a 
bolder step in their own lives and in their own communities. So 
space exploration is therefore an opportunity for us to create 
a better educated, more united society.
    At ASU I'm also co-chair with President Michael Crow of our 
new Interplanetary Initiative. In this initiative, we're 
bringing together not just the technological but the 
educational and the social aspects that we need for our space 
future, and indeed, education is the single most critical thing 
for humanity's future. Both at ASU and at our startup, Beagle 
Learning, we are working on next-generation learning. We need 
to produce a critical mass of people who are attracted to the 
unknown, who are learning how to ask better questions, who are 
willing to pursue answers through partial solutions, and who 
know how to build teams and to lead. All this ideation is 
initiated by the vision and the process of NASA, and in fact, 
space exploration will bring us to a better future here on 
Earth as well as eventually on the moon and Mars and beyond.
    Thank you very much.
    [The prepared statement of Dr. Elkins-Tanton follows:]
    
    
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    Chairman Babin. Thank you, Dr. Elkins-Tanton.
    Now I'd like to recognize Dr. McKinnon for five minutes for 
your testimony.

             TESTIMONY OF DR. WILLIAM B. MCKINNON,

            CO-CHAIR, NATIONAL ACADEMY OF SCIENCES,

        COMMITTEE ON ASTROBIOLOGY AND PLANETARY SCIENCE;

           PROFESSOR OF EARTH AND PLANETARY SCIENCES,

               WASHINGTON UNIVERSITY IN ST. LOUIS

    Dr. McKinnon. Good morning, Mr. Chairman, Members of the 
Committee.
    So I'm here today because I'm a Co-Chair of the Committee 
on Astrobiology and Planetary Sciences, or CAPS, for the 
National Academies, but I wish to say that my testimony today 
is my own and is not an official report from CAPS or the 
Academies. Nevertheless, I hope you find my remarks useful.
    So I'd like to focus on the Planetary Science Decadal 
Survey and its relation to flagship and other planetary 
missions. Obviously decadal surveys are carried out about every 
ten years for various space science disciplines and the 
Committees and the panels that carry out the decadal are drawn 
from the broad community associated with the discipline in 
question. Decadal survey recommendations to the government play 
a critical role in defining our country's agenda in a given 
science area for ten years or even longer.
    Now, the Planetary Science Decadal Survey was tasked in 
particular, among many things, to create a prioritized list of 
flight investigations because missions lie at the heart of 
planetary exploration. Such a prioritization is based first and 
foremost on science, especially science per dollar, but also on 
programmatic balance among mission targets and balance among 
mission types--small, medium and large. Indeed, a balanced mix 
of discovery, new frontiers and flagship missions enable both a 
steady stream of new discoveries and the capability to address 
larger challenges such as sample return missions or outer solar 
system exploration.
    Prioritization also considers technological readiness, the 
availability of trajectory opportunities, understanding of cost 
and technological risk, and the fiscal climate. Anyway, these 
prioritizations take in the sense that decadal surveys succeed 
because the consensus they represent is compelling.
    Now, in terms of science, increasingly central to NASA's 
exploration of the solar system is the emerging science of 
astrobiology, prominent examples being the scientific program 
of the Curiosity Mars Rover, the Mars 2020 rover, the 
development of the Europa Clipper mission, and the planning for 
the potential future landing on the surface of Europa and the 
inclusion of ocean worlds in the recent new frontiers call.
    Indeed, in the most recent Planetary Decadal Survey, 
astrobiology was a driving scientific rationale for the two top 
mission recommendations now being implemented as Mars 2020 and 
Europa Clipper. Now, my personal assessment, and as the CAPS 
leadership has previously reported to the Space Studies Board, 
is that NASA's Planetary Science Division is doing well and the 
Decadal Survey's priorities and recommendations are being 
pursued. Mars 2020 and Europa Clipper in particular are, I 
believe, responsive to the Decadal Survey in science and cost.
    Now, regarding NASA's plans to explore Europa, CAPS, as 
well as the ongoing Academies' planetary mid-term review will 
continue to consider the aspects of--consider the impacts of 
the evolution of this program. Presently, NASA has been 
directed to add a lander to the Europa exploration program. The 
development of any large mission like that is of course a 
programmatic challenge and can have unwelcome or worse effects 
on a broad cost-contained program. But this challenge must be 
balanced against the scientific opportunity afforded by the 
promise of addressing one of the greatest of scientific 
questions: is there extant life beyond Earth?
    As I said, these are all issues I expect CAPS will continue 
to consider and will also be surely considered by the next 
decadal as well.
    So to finish up, Mr. Chairman, as a second grader I watched 
the liftoff of John Glenn and Friendship 7 in our auditorium, 
and as a teenager at home I watched Neil Armstrong walk on the 
moon. Over the past 60 years, I have seen NASA's exploration of 
the solar system from Mercury out to Pluto and beyond, 
revolutionize our conception of ourselves and our planet, but I 
believe given our ongoing discoveries and characterization of 
planets around other stars, thousands of them we know about 
now, and the very real possibility of detecting extant life in 
our solar system that we are approaching an even greater 
revolution, a true paradigm shift in our understanding of our 
place and our destiny in the universe.
    Thank you very much.
    [The prepared statement of Dr. McKinnon follows:]
    
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    Chairman Babin. Thank you, Dr. McKinnon. All fascinating 
testimonies. I really appreciate it. The Chair now recognizes 
himself for five minutes.
    Dr. Green, in the near future, NASA's Planetary Science 
Division may be running three flagship missions at the same 
time: the Mars rover for launch in 2020, the Europa Clipper for 
launch in 2022, and potentially a Europa lander for launch in 
the 2024 time frame. I greatly support this investment and 
NASA's renewed focus on deep space exploration. At the same 
time, from an acquisition perspective, this is a great deal of 
work. What is NASA doing to address the risks of cost and 
schedule slips associated with this cadence of flagship 
missions?
    Dr. Green. Planetary Science I think has tackled a number 
of those topics and is doing quite well because we started to 
implement a couple very important and new procedures. 
Typically, strategic missions in the past based on a science 
rationale that's almost at any cost. In Planetary Science, we 
begin the--we have begun the process in particular with Mars 
2020 to have a cost-constrained environment. As was recognized 
on the Planetary Decadal, both the Mars Cacher and the Europa 
Clipper were unaffordable, and we took on a process early in 
this decade to begin to determine what science we can do at 
that reasonable cost. We're leveraging on Mars 2020 the 
architecture for Curiosity. We've done a lot of work on the 
planning of the Europa Clipper where we're looking at descope 
options, and so some of these processes are incredibly 
important for us to follow through on.
    Chairman Babin. Okay. Thank you very much.
    And now the next question to Dr. McKinnon. To what extent 
do the Mars Rover 2020 and Europa Clipper missions align with 
the Decadal Survey recommendations?
    Dr. McKinnon. Well, the original survey considered two 
flagship-class missions, Mars astrobiology Explorer-Cacher and 
a Europa Jupiter orbiter mission, a mission to orbit Europa 
itself, and in both cases the Decadal Survey concluded based on 
a very detailed cost and technical evaluation that these 
missions were probably too expensive to be carried out in the 
decade in question. And so basically they said these were our 
priority missions but they needed to be descoped. They needed 
to be reduced in cost and perhaps reduced--and certainly 
reduced in risk. And in both cases, I think they've done that. 
As an example, the Europa mission doesn't orbit Europa anymore 
but it orbits Jupiter but repeatedly passes by Europa dozens of 
times and basically recovers all of the science, and in fact, 
in my own view actually does an even better job because it 
avoids so much of the radiation that's near Jupiter and it 
allows in its long looping orbits around Jupiter that Dr. 
Pappalardo can tell you about, it can radio back all the data 
that it collects every time, and it does it within a very 
reasonable cost cap.
    Chairman Babin. Thank you very much.
    Now, I also would like to ask Dr. Farley and Dr. 
Pappalardo, the exploration of Mars and Europa are inspiring 
and truly amazing. As Project Scientists for Mars Rover 2020 
and the Europa Clipper, can you share with us what excites you 
about these exploration efforts, and what are the greatest 
scientific discoveries that you're hoping to achieve?
    Dr. Farley. Well, I think the most exciting thing about 
Mars is that, as I mentioned in my testimony, the surface of 
Mars is--carries a rock record from a time period which is 
completely obliterated on Earth. There is no substantial rock 
record that is older than about 3.6 billion years on Earth. 
Those rocks are present on the surface of Mars, and they will 
tell us a lot both about the way rocky planets evolve and also 
about things like habitable environments, and for me, linking 
this to the life question, I think the really exciting thing 
is, we will potentially be looking at an environment that was 
capable of having life originate, and that's of course one of 
the great questions. It's a great scientific question that is 
extremely difficult to treat as a science question because 
there's no evidence, no substantial evidence to compare it 
against. By going to Mars, we may actually be able to find 
environments like that and learn something really profound 
about the way life works.
    Chairman Babin. Thank you very much.
    And Dr. Pappalardo?
    Dr. Pappalardo. For Europa, we want to understand, is this 
really a habitable environment, Europa's ocean, lakes within 
the ice shell, and we think we know how Europa works but 
planetary scientists are always surprised when we actually go 
there with new instruments to test hypotheses. So we're going 
to both test hypotheses and explore and expect to be surprised. 
What I would love to see is some sort of oasis, that is, a 
place where there's liquid water near the surface, there's 
evidence of heat coming out, there are organics at the surface 
somewhere where we'd want to follow up with future exploration.
    Chairman Babin. Fascinating. Thank you. My time is up so 
I'd now like to recognize the gentleman from California, Dr. 
Bera.
    Mr. Bera. Thank you, Mr. Chairman.
    Dr. Elkins-Tanton--and I think each of you in your opening 
statements alluded to the fact that exploration is part of our 
DNA, you know, this natural curiosity, this desire for 
discovery, and the universe is, you know, unlimited in its 
possibilities of what we can learn. That brings us back down to 
Congress where we have to operate in the confines of limits. 
Each of you has talked about the Decadal Survey and alluded to 
a bit of the roadmap for some of our bigger missions and laying 
out some of the parameters for some of the medium-size 
missions.
    Dr. Elkins-Tanton, as you talked about the Psyche mission 
and alluded to the importance of, you know, some of our smaller 
missions, how those--you know, what we discover, you know, 
they're able to be launched at a lower cost, et cetera. You 
know, there's some worry in that limited environment of 
Congress that we potentially focus on the big missions at the 
expense of the smaller missions, and we've got to found the 
right balance. Maybe if you want to expand on your comments and 
the importance of some of the smaller missions.
    Dr. Elkins-Tanton. Thank you very much. Indeed, I think 
this is well recognized at NASA, and I've heard Jim Green talk 
about a cadence, a process for deep exploration in space that 
you might fly by, you might orbit, you might land, and then you 
might rove, and indeed, you wouldn't spend all the money that 
you would have to spend to do a flagship mission on a body that 
we know little about, and so the smaller missions form a 
framework and they set the stage for the kinds of bigger 
expeditions that we want to do, and as my colleagues here have 
mentioned, every time we do something in space, it surprises 
us, and so we must try these smaller missions to find out where 
the biggest surprises are and then put our money on making the 
big, big discoveries.
    Mr. Bera. Dr. Green, do you want to expand on the 
importance of the smaller missions?
    Dr. Green. Indeed, the smaller missions are really our 
pioneers. They do go out and do some initial exploration. You 
know, smaller missions in the discovery framework is really the 
heart of that exploration process. You know, I mentioned 
several of them in my testimony like Dawn. Others that have 
come and gone while I've been at NASA headquarters include 
Messenger, another wonderful mission. Grail went to the moon, 
Messenger went to Mercury, and Grail studied the moon in new 
and unique ways.
    And so indeed, the discovery line is really quite important 
for us, and then the next line is new frontiers. This is where 
we can now concentrate on the next level of detail. So 
important for us to make decisions on what our next flagships 
will be.
    Mr. Bera. Great. Switching now to Mars and, you know, our 
telecommunications infrastructure and Mars, my understanding 
right now is that the Mars Reconnaissance Orbiter handles the 
majority of our telecommunications relay for Curiosity Rover, 
but the MRO was launched 12 years ago. As we look at Mars Rover 
2020, you know, I guess, Dr. Green or Dr. Farley, would you 
like to kind of comment on, you know, will we still be relying 
on the MRO to relay that information back or are we thinking 
about, you know, what next steps for telecommunications?
    Dr. Green. Well, telecommunications for any surface assets 
indeed go through our orbiters, and right now we have a 
wonderful network including MRO is Mars Odyssey, and also with 
partnership from ESA, other missions that are also orbiting 
Mars have that telecommunication capability. So in addition to 
those two, we also have with ESA the Mars Express mission and 
now the newly inserted into orbit, the Trace Gas Orbiter from 
ESA. Now, we also have Maven, which is not prime 
telecommunication capability but may become more dependent on 
using Maven as our aging assets occur. So indeed, supporting 
telecommunications is a real critical element of allowing us to 
now when Mars 2020 gets down on the ground be able to relay 
that data back so we take careful operations of all those 
missions and partner with other agencies.
    Mr. Bera. Great. Dr. Farley, do you want to expand or----
    Dr. Farley. I'll just say Mars 2020 has a very large demand 
to downlink data. We have a huge number of cameras. It's quite 
extraordinary. There's more than 20 cameras on the rover. And 
we will need downlink. As you point out, MRO is an aging asset 
but as Dr. Green pointed out, there are contingency plans to 
get us the data volume we need.
    Mr. Bera. Great. Thank you. And I'll yield back.
    Chairman Babin. You bet. Thank you. Good questions.
    I now recognize the gentleman from California, Mr. 
Rohrabacher.
    Mr. Rohrabacher. Thank you very much, Mr. Chairman. It was 
noted earlier that one of the purposes of, or one of the 
benefits, I should say, of your activities is that you have 
these robots all over the universe and beyond that you are 
inspiring people with our capabilities.
    And Mr. Chairman, let me just note that I've been around 
for a while, and I think that when we were deciding about the 
shuttle and we were deciding about Space Station, a lot of 
times the discussion was only on the immediate scientific 
payback, but I believe those two space projects have inspired 
generations of Americans now, and who knows how much more 
productive our people are, how much more visionary they are 
because of these investments in the shuttle and the space 
station, which were very expensive projects, I might add.
    And back to expensive projects, let me just note that one 
thing that I find--one of our witnesses mentioned that the 
Decadal Survey was supposed to prioritize and it just seems to 
me standing back and listening to everything that we haven't 
had that prioritization and maybe we should--there's been--when 
you have so many projects at one time, it indicates that there 
hasn't been a real finding out of what priorities we need, and 
I'm certainly not an expert enough to tell you what those 
priorities should be.
    Let me ask some specific concepts or ideas about the 
engineering that I don't know about. What type--well, first of 
all, is there any one of these missions that plan to--we know 
we've landed the robots on Mars. Do we plan to actually bring 
some material from Mars back to Earth before we plan to send 
human beings there and bring them back?
    Dr. Green. Indeed, the Mars 2020 mission, which is going to 
core rock, providing a detailed look at the past Mars, the 
geological records in that rock, we are currently looking at a 
variety of architectures, and----
    Mr. Rohrabacher. Right, but we are going to bring them 
back?
    Dr. Green. Our intention would be indeed that as the 
importance of these samples are noted based on the analysis 
that we do in situ that indeed we would plan on bringing 
samples back from Mars.
    Mr. Rohrabacher. Okay. The reason I ask that is, it seems 
to me that rather silly to think that if we can't bring back 
rocks that we're going to bring back people, and certainly if 
we aren't comfortable with the idea that we can bring back 
rocks, we should be focusing on getting that done before we 
talk about bringing people back.
    The exploration, to me, that's the most inspiring. I just 
have to tell you that when we talk about going out and visiting 
those places where nobody has been, what type of fuel are we 
using? There was a mention about one of the things when we run 
out of fuel, it's going to land into Europa or something like 
that. What type of fuel is now being used in these various 
projects? We know you have to have a big rocket to get them 
going, but if they're going to keep going into the universe, 
what fuel do they use?
    Dr. Farley. Yeah, Mars 2020 while it's on the surface will 
use a short-lived plutonium isotope so it's a nuclear power 
source.
    Mr. Rohrabacher. Any other----
    Dr. Elkins-Tanton. May I add to that? During cruise and 
while orbiting Psyche, our spacecraft will use solar electric 
propulsion, and this to me is so--it's in our heart at space 
age. You see the little blue plumes of the ions being shot out 
the back and it's all run by solar power, and in fact, this is 
another good proof of this technology which is eventually going 
to be critical for getting people to Mars.
    Mr. Rohrabacher. Yeah, I remember the solar sail project, 
which also was very exciting. These new concepts that--and 
you--and let me just note, Mr. Chairman, the fact that we can 
actually provide a fuel for something that far away indicates 
that maybe we have some knowledge that's going to really help 
us here.
    But one last thought. I would hope that--again, I think the 
Moon is close by and whatever we can actually get a benefit of 
going back there, we should before you take the next step. 
However, the most important thing was, if Mars--can I ask 
permission for one minute for this question? And that is, you 
have indicated that Mars was totally different thousands of 
years ago. Is it possible that there was a civilization on Mars 
thousands of years ago?
    Dr. Farley. So the evidence is that Mars was different 
billions of years ago, not thousands of years ago.
    Mr. Rohrabacher. Well, yes.
    Dr. Farley. And there would be--there's no evidence that 
I'm aware of that----
    Mr. Rohrabacher. Would you rule that out? See, there's some 
people--well, anyway----
    Dr. Farley. I would say that is extremely unlikely.
    Mr. Rohrabacher. Okay. Well, thank you all, and thanks for 
the good job you're doing. God bless.
    Chairman Babin. Thank you, Mr. Rohrabacher. I'm looking 
forward to finding out what's up there, that's for sure. And 
just last month, we had a great hearing in here on in-space 
propulsion, which was super, super interesting.
    Okay. Now I recognize the gentleman from Colorado, Mr. Ed 
Perlmutter.
    Mr. Perlmutter. Thanks, Dr. Babin.
    And good morning, and thank you for your testimony today, 
and a truism in life is, everything's relative, and when we're 
talking about small, medium and flagship projects that you all 
are undertaking, you know, to Mrs. McGillicuty from Lakewood, 
Colorado, they're all major undertakings, and Dr. McKinnon and 
Dr. Elkins-Tanton, I mean, we're here for I dipped into the 
future far as human eyes could see, saw the vision of the world 
and all the wonder that would be. And all of you are working on 
kind of the ultimate question of humanity, why are we here and 
what else is out there. And so I just appreciate your 
willingness to take on kind of the nuts and bolts for us to 
start knowing the unknown, and this Committee is so exciting to 
all of us here and to hear the work you're doing, we appreciate 
it.
    Now, I'd like to start with Dr. Farley. One of the things 
that I am focused on is trying to get our astronauts to Mars 
by--you guessed it--2033, all right, and so first question I 
have is for you. How will this rover, you know, 2020, our 
mission in 2020, how will that help us, inform us to get humans 
to Mars by 2033?
    Dr. Farley. Well, I think it's important to note that Mars 
2020 has a very strong collaborative involvement from the human 
side of NASA, and that is manifested in several different ways. 
Most notably, you heard about the MOXIE demonstration of in 
situ resource utilization. In addition, we have a weather 
station, which will characterize the environment, will also 
characterize dust, and dust on Mars is a big concern for human 
explorers, and in addition, during entry, descent and landing, 
we'll have a very sophisticated observation package. 
Understanding what goes on during EDL is absolutely critical 
and almost impossible to simulate either on a computer or in an 
analog experiment on Earth, so this is very important data, and 
as Dr. Green mentioned in answer to the question of, you know, 
bringing rocks back before people back, it's a very sensible 
thing to do. Obviously there's no commitment to do that but 
there will be a tempting target to learn from when those 
samples come back.
    Mr. Perlmutter. Dr. Elkins-Tanton, where the heck is 
Psyche, I mean other than up here or wherever it might be?
    Dr. Elkins-Tanton. Psyche is in the outer main asteroid 
belt between Mars and Jupiter. It's about three times farther 
from the sun than the Earth is.
    Mr. Perlmutter. Okay. Dr. Pappalardo, my question to you, 
you know, often I talk about Star Trek or Star Wars or Men in 
Black but what you're doing reminds me of 2001: A Space Odyssey 
and, you know, our mission at that point to get to Jupiter. So 
explain to me in this investigation, study of Europa, what are 
the--I mean, what do you really--what do you see already and 
what do you expect to see from this mission?
    Dr. Pappalardo. Let me preface by saying I'm a big Trekkie. 
And our Europa science team of about 130 people we have as our 
mascot, our totem, a giant monolith that we tote around our 
meetings.
    So we have tantalizing hints from the Galileo mission about 
what Europa is like. At high resolution we have precious little 
data. We have one six-meter-per-pixel image. We have ten-meter-
per-pixel images that you can count on your hands and toes to 
get an idea of what Europa is like, and so this creates this 
picture of what we think it's like, an ice shell probably about 
20 kilometers thick above a saltwater ocean and then the rocky 
mantle below. But, you know, right now it's kind of a uniform 
picture whereas any world you explore in more detail and then 
you find out how it varies from place to place. We've seen this 
happen with our understanding of Mars where we first thought it 
was a cratered ball because we saw the cratered part of it and 
then we started understanding more and more, and now it's at 
the outcrop scale we see differences. So we're going to 
understand how Europa works as a world. We're kind of in our 
level of understanding that we were before plate tectonics on 
Earth where we don't really get how all the little pieces we 
see at the global scale fit together and we're going to find 
more little pieces as we explore with Europa Clipper.
    Mr. Perlmutter. Thank you----
    Dr. McKinnon. If I could----
    Mr. Perlmutter. --Mr. Chair, and I yield back.
    Dr. McKinnon. I'll just pipe in just for a second.
    Mr. Perlmutter. Oh, I'm sorry.
    Dr. McKinnon. We're--you know, we have tantalizing evidence 
from the Hubble space telescope that Europa's venting material 
into space, and we hope when we get there we'll be able to 
confirm that and literally fly through it and sample it and 
analyze it.
    Mr. Perlmutter. Thank you, Doctor.
    Chairman Babin. Thank you. Good questions and great 
answers.
    I now recognize the gentleman from Oklahoma, Mr. Lucas.
    Mr. Lucas. Thank you, Mr. Chairman, and I share my 
colleagues' enthusiasm up here and clearly the enthusiasm of 
the panel.
    Let's visit mechanically for a moment, Dr. Farley, about 
the nature of the rover programs. A lot of citizens back home 
are very sensitive about how we spend their money. Could you 
take me through a discussion about Mars Rover 2020, the 
advances and the technology and the science gathering used in 
that compared, say, to Curiosity as I explain to my 
constituents back home why it's important we do this?
    Dr. Farley. Okay. Well, in reference to Curiosity, the 
reason this mission can be done in a cost-constrained way is to 
take advantage of the platform that the Mars Science Laboratory 
developed. It should not be underestimated how difficult any 
new undertaking in space is. So we start off with that, and 
this allows us to actually focus on the stuff that is new, and 
there are new science instruments that will make new kinds of 
observations, and I think those--they will be directed towards 
characterizing samples that will form the basis of a discussion 
as to whether those samples should be brought back, and if 
those samples are brought back, I think they will revolutionize 
our understanding of many different things.
    If you look at the history of our understanding of many 
aspects of the solar system, it was completely changed by the 
return of the lunar samples, and that of course is an 
abiological world. My expectation is, if samples come back from 
Mars, this will be a revolution that goes way beyond sort of 
planetary science and geology. It will actually extend into 
asking and looking at samples for the first time to address 
questions about what life not as we know might look like, and 
I'll just put it out there as a profound question for which we 
don't have an answer, how does one look for life as we don't 
know it? And we may have samples in our collection in 20-some 
years where we will need to answer that question. I think the 
public will be fascinated by that question.
    Mr. Lucas. Dr. Pappalardo, discussing the plumes just a 
moment ago, tell us mechanically about what it will be involved 
in being able to use the Clipper in a way to verify their 
existence, whether it's navigating the flybys or the sensors on 
board. Expand for just a moment on that if you would.
    Dr. Pappalardo. Well, first, there're continuing 
observation with the Hubble Space Telescope so we hope, expect 
to have new data before we arrive so we can understand if 
they're real, if they're periodic in some way. But say we don't 
or say they're sporadic and we need to understand them better. 
We would use the time--we have a big looping first orbit. We 
would use that time to monitor and try to understand whether 
there is evidence of plumes, both from imaging and from 
ultraviolet observations where we could see the glow from such 
plumes. And then during the mission, we're planning on 
monitoring the whole time when we're a little farther from 
Europa to look for plumes. And then if there are plumes, then 
we will certainly want to target them. Whether it be in the 
primary mission or the extended mission, we'll figure that out, 
but we'll want to fly through as low as possible, meaning about 
25 kilometers, 16 miles off the deck if we can, depending on 
the location, depending on whether we can or not, and for that 
matter, how much particulates because you can damage--you can 
risk the spacecraft, and by flying through, we'd be able to 
sample that stuff directly and get a direct sampling of what's 
in the interior of Europa. We don't know for sure. Assuming the 
plumes are real, we don't know for sure if they're coming from 
the ocean or from lakes within the ice shell, and we would 
analyze the gas and the dust that's coming off to say a lot 
about what the interior composition of Europa is like.
    This is analogous to what Cassini has done at Enceladus at 
Saturn, which does have plumes that spew into space.
    Mr. Lucas. So an incredible amount of prep, an incredible 
amount of skill in maneuvering the mission, and just a little 
bit of luck would be a good thing too.
    Dr. Pappalardo. And we have a group of scientists. We're 
thinking that through as we meet and discuss the possibilities 
and working with the engineers to do so.
    Mr. Lucas. Absolutely. Thank you, Doctor.
    Yield back, Mr. Chairman.
    Chairman Babin. Thank you.
    I now recognize the gentleman from Virginia, Mr. Beyer.
    Mr. Beyer. Dr. Babin, thank you very much, and thanks to 
all of you for being here.
    Dr. Farley, a relative softball question, but in your 
testimony, you say that past life Mars 2020 seek evidence of 
past life in a fossil-like Earth-like environment that existed 
in the first billion years after the dawn of the solar system--
some of the most profound scientific questions of our time. Why 
are they profound?
    Dr. Farley. Well, the two questions that I was alluding to 
there are the, is there life beyond Earth, and I will just make 
the general observation from my interaction in the science 
community, the discovery of thousands of extrasolar planets has 
converted this question from something where most scientists 
that I knew would say it doesn't seem that likely to wow, it 
seems really unlikely that we are alone. The only way I think 
you could really put some scientific evidence to that is, if 
you look in a habitable place, is it inhabited? There may be 
lots and lots of habitable places out there, and that goes to 
the question of the spark that makes life happen, and so that I 
think is a really profound question that we will go after. Is 
life out there? Was it out there? And what is necessary--what 
are the environments like where life might evolve, and those 
are really profound questions.
    Mr. Beyer. Thank you very much.
    Moving from life to metal, Dr. Elkins-Tanton, a couple of 
quick questions. How do we know that it's metal? Is it a 
spectrometer or whatever? How do you know it's the only one in 
the solar system? Why did you name it Psyche? And do you really 
think it used to be a planet and the rock and the like was 
stripped off of it, that it was like Earth or Mars or Venus?
    Dr. Elkins-Tanton. Right. Okay. Let's see if I can remember 
this and get it all in your time. So the first question is how 
do we know it's metal. We've never seen Psyche visually as more 
than a dot of light but we get radar returns from Arecibo, 
which seems to me to be also just a technological miracle. We 
can actually send radar from Arecibo, get the returns, see that 
the radar has interacted with the material of Psyche in a way 
that it only interacts with metal, so that's a really key one. 
We can also see its reflected spectra consistent with metal and 
its density consistent with metal but the radar returns are the 
key. So we're pretty certain it's metal. There are other 
smaller metal asteroids like Cleopatra, which is shaped like a 
dog bone. If you haven't seen it, you should google it. It's a 
great one. But they're all much smaller. They seem to be the 
shrapnel of leftover from planetary collisions. All the really 
heavy, rocky, metallic material is either in the inner solar 
system or in the asteroid belt or hidden inside ices and gases 
in the outer solar system. So we're pretty sure that what we 
see in the asteroid belt is it for metal and Psyche's the only 
big round one.
    Now, Psyche was discovered in, I believe, 1852 maybe--I 
might have the date wrong--by an astronomer in Naples, and he 
named it Psyche. It was the 16th body found in the asteroid 
belt by a group of astronomers called the Celestial Police who 
were trying to set right to the solar system and find the 
planet that was there, and they didn't, and they were naming 
them all after gods and goddesses, and so Psyche's number came 
and there it is, Psyche.
    There was one more question. What was it?
    Mr. Beyer. Did it used to be a planet?
    Dr. Elkins-Tanton. Oh, we're pretty sure it was but, you 
know, true to my scientific training, everywhere I've been in 
the world and given talks on Psyche, I've asked scientists what 
else could it possibly be. If it's not the core of a planet, 
how do we make this? And our best other guess is that it could 
be material that had all the oxygen stripped off it by heat 
very close to the young sun. Theoretically, people think that 
kind of material could exist but we've never found an example 
of it, and so if it's not a core, that would actually be more 
exciting. It would be something we've never seen before.
    Mr. Beyer. Exciting either way.
    Dr. Elkins-Tanton. Thank you. I think so.
    Mr. Beyer. And I want to point out that Jules Verne did 
think we could do a journey to the center of that Earth.
    Dr. Elkins-Tanton. I visited that Icelandic volcano. It 
didn't work for me.
    Mr. Beyer. Dr. Green, you talked about looking for evidence 
of organic materials on Ceres and that Bennu--I hope I 
pronounced it right--is believed to contain water and organic 
compounds such as amino acids. Have we gone beyond amino acids 
to proteins to nucleic acids? Are we going to leap to DNA and 
RNA?
    Dr. Green. Well, of course, we would call that an ever-
increasing knowledge about potentially the right stuff that 
life either is made of or produces as a byproduct. That's all 
part of what would be a ladder of life but the only way we can 
definitively determine what's really at Bennu is to bring 
samples back, and that indeed is planned. When we get into 
orbit around Bennu, as we start getting August of next year, 
we'll be studying it for about 500 or so days picking the right 
location, going down, sucking up material, perhaps as much as a 
kilogram, and then bringing that material back, and that's when 
we'll do the detailed look at what's in it. It'd be great to 
find more complex amino acids and other organics.
    Chairman Babin. Thank you, Mr. Beyer.
    I now recognize the gentleman from Florida, Dr. Dunn.
    Mr. Dunn. Thank you very much, Mr. Chairman. I think the 
Space Subcommittee always seems to be most inherently 
optimistic committee of the House, and you know, the can-do 
attitude of our panelists is absolutely infectious. I can only 
hope that you'll expose yourselves to the Senate sometime soon.
    I want to frame my questions to the panel with this 
thought. The proof of life that is truly extraterrestrial life 
is an event that is on the level with the first Moon landing, 
so long after posterity's forgotten all of the proceedings of 
this Committee and relegated the history of our planetary 
explorations to the dusty bookshelves, everyone will remember 
the event that proved extraterrestrial life.
    So with that thought, Dr. Farley, let's say everything 
works out perfectly on the Mars 2020 lander. You obtain 
appropriate terrestrial samples. What would you consider to be 
the elements of a biosignature, you know, a biotic chemistry, 
if you will?
    Dr. Farley. So I'll give two different answers to that. One 
is, what can we detect with the rover and what could we defect 
if we bring samples back, and with the rover, we have the 
capability to make a map at the scale of about a postage stamp 
of the distribution of organic matter. That's one of our key 
observational capabilities, to take a rock and make a map of 
organic matter, and on that same postage stamp-size piece of 
material, we can also map the elemental composition. And when 
one looks at ancient terrestrial rocks, this co-registration of 
organic matter and elemental composition is the key to 
identifying on a planet where you already know there's life to 
identify the most ancient life on Earth. So we will make those 
kinds of observations, but just like with the terrestrial case, 
those kinds of observation are seldom definitive. They're the 
kind of thing people argue about for decades, and if we bring 
samples back, they're a far greater diversity of observations 
we can make. Dr. Green was talking about different--making 
observations of the ladder of life, looking for more and more 
complex organic molecules whose composition is only reasonably 
associated with life as opposed to abiological processes.
    Mr. Dunn. I guess I kind of thought the problem with 
bringing it back is everybody always wonders about 
contamination, you know, did you sterilize the ship so 
thoroughly on the way out and the way back that you can be 
certain that this came from Mars. So if you do a test as they 
did on the Viking, they are in in situ on Mars, and if you 
could design a better test, a better chemical test, what would 
that be and would it involve, as you and I spoke before the 
meeting, stereoisomers and----
    Dr. Farley. So one of the complications of looking for 
ancient life is that there will be degradation of organic 
molecules.
    Mr. Dunn. You're looking for ancient life. I'm looking for 
life today.
    Dr. Farley. Right. We have no capability on the rover to 
look for extant life at the microbial scale. We can't tell the 
difference between live and dead, but if those samples came 
back, as I mentioned before, I think there will be a lot of 
interest in actually developing technologies, and they would 
include things like stereochemistry and that sort of thing.
    Mr. Dunn. So would you elaborate? Because I'm not sure 
everybody on the Committee is thinking about stereochemistry. 
What's the significance of discovering an ongoing biochemical 
or chemical process, a biotic process that has, you know, 
solely left- or right-handed metabolite?
    Dr. Farley. Sure. So one of the key ways that one 
identifies molecules that are involved in life is that all life 
has a preference for a particular handedness of one of the 
organic molecules. There's two different confirmations that 
these organic molecules could be in and most abiological 
processes produce them in equal abundance whereas life because 
it has a machinery involved, very specific machinery, tends to 
produce a specific chirality, a specific confirmation of these 
organic molecules. So this is really a critical observation for 
establishing that life is involved. There are very, very few 
abiological processes that would produce stereochemically 
specific molecules.
    Mr. Dunn. So production of a stereospecific metabolite 
would be a pretty strong presumptive proof of life, extant 
life, on Mars if you ran it the way the Vikings rover ran that? 
What the Viking rover did is run that test without 
stereoisomers.
    Dr. Farley. Right.
    Mr. Dunn. So if you ran the same test and checked for 
stereoisomers by having left- or right-handed substrates----
    Dr. Farley. Yes, that would be a very important test, and 
I'm aware that there are instruments under development for 
actually making those kind of measurements in space.
    Mr. Dunn. I agree there are. I'm out of time. I would say 
that that's about a 2-kilogram package. I look forward to 
talking to you outside of the Committee structure, and I yield 
back.
    Chairman Babin. Thank you. You remember a lot from your 
training, Dr. Dunn.
    Let's see. Another gentleman from Florida, Mr. Posey.
    Mr. Posey. Thank you, Mr. Chairman.
    Dr. Green, traditionally, planetary exploration was a 
public sector endeavor that taxpayers took care of. Today the 
U.S. private sector companies are beginning to invest and 
develop planetary exploration programs. What is NASA doing to 
facilitate and encourage private sector investment and 
participation in planetary exploration?
    Dr. Green. I believe there's a whole range of things that 
we've been involved in. If you take an example of the concept 
of going to asteroids and being able to extract certain metals 
and other compounds of interest, the first thing that they're 
going to need to know is, where are they, what is their 
characteristics, how to get to them, and indeed, we are doing 
an extensive finding project where we'll find our small bodies, 
we'll catalog and characterize them, and all that information 
will be critical, and we've discussed that openly in many 
different meetings working with that sector.
    Another sector is a series of commercial opportunities 
going to the moon. Now, this could be a really important 
element for scientists to be able to work with the commercial 
entities and be able to obtain rides to be able to bring back 
material or examine certain regions on the moon that are 
extremely important. The moon is still quite valuable in terms 
of being able to provide us an enormous amount of science that 
be done. It's been a witness plate of over 4 billion years of 
impacts and can tell us a lot about what's happened to our 
environment and what's happened to the Earth. So those 
partnerships are beginning. There are some that are done 
through a Space Act agreement and others are done through 
collaborations and discussions at a variety of venues.
    Mr. Posey. Thank you very much. That's a good answer.
    Given the important role of robotic planetary missions in 
advancing human exploration capabilities, how can the current 
and future planetary missions be integrated into the human 
exploration roadmap, which we've asked NASA to produce?
    Dr. Green. Well, of course, from my perspective, planetary 
scientists are really the guides. You know, they're really the 
ones that go out first. Human exploration is not Star Trek. 
It's not ``go where no human has gone before.'' In our program, 
and NASA is really all about sending humans to locations beyond 
low-Earth orbit out into the solar system, be able to live, 
work, but also return, and all those require not only where 
you're going but the characteristics so how to get there, what 
are the kind of science and other activities one can do on 
station, and then of course the challenges of entry, descent 
and landing for any of the bodies they choose to go to.
    We pioneer a lot of that, you know, in terms of being able 
to look at those environments, collect that information, but 
also pioneer some of the initial technologies that allow us to 
get our rovers and other machinery at various locations, 
whether it's the moon or Mars.
    Mr. Posey. Can you describe the infrastructure that 
missions will be putting in place around Mars and Europa to 
support future missions? For example, will NASA be able to use 
the Europa Clipper to support future Europa missions, namely 
the lander?
    Dr. Green. Yeah, actually as Lindy mentioned earlier, in 
planetary science, we really have a very important paradigm 
that we follow. It's flyby, orbit, land, rove, but also return 
those samples. And indeed, the Europa Clipper gives us that 
opportunity to do a detailed examination of Europa that 
provides high-resolution imaging that gets us right to where we 
want to go that makes the next mission, which would be 
notionally a lander, to be able to land safely and perform the 
science that we wanted to do. So indeed, each of these missions 
are very much related and depend on the success of the previous 
mission.
    Mr. Posey. Thank you very much. I yield back, Mr. Chairman.
    Chairman Babin. Yes, sir. Thank you, Mr. Posey.
    And another gentleman from Florida, Mr. Webster.
    Mr. Webster. Thank you, Mr. Chairman.
    Dr. Green, is there any interest in going to the outer 
planets to do the same level of investigation and so forth, or 
is that just too expensive and too far?
    Dr. Green. Well, indeed, when one looks at the science 
that's been delineated by the community and the National 
Academies' Planetary Decadal, we have an extensive desire to be 
able to go out to the outer reaches of our solar system where 
our planets like Neptune and Uranus reside. Neptune and Uranus, 
although they are big what look like giant planets like Saturn 
and Jupiter, they actually are very different in many ways. 
They have a whole series of different compositions associated 
with them. We call them the ice giants. You know, they're not 
completely hydrogen and helium. They have ammonias and a whole 
series of other elements that they have obtained in that 
accretion process that we know very little about and so being 
able to go out to Uranus and Neptune are extremely important.
    We just completed a major study and have worked with the 
scientific community to determine what are the characteristics 
of the measurements we want to make in those regions but also 
how do we be able--how are we able to get out there perhaps in 
the second half of the next decade and really get into orbit 
and analyze that environment.
    Mr. Webster. Is that desire which you spoke of funded?
    Dr. Green. Right now that's only at the study level. The 
Planetary Decadal is quite clear that the top things that we 
should be doing we are doing but, you know, you have to 
prepare, you have to spend some time on your future or you 
don't have that future, and so while we do this planning, while 
we do this mission concepts and studies, those are indeed 
laying the groundwork for our future work.
    Mr. Webster. Is Voyager still broadcasting?
    Dr. Green. Yes. Both Voyagers are still broadcasting. Now, 
they're very far away. They're more than 120 astronomical units 
away where one astronomical unit is the distance between the 
Sun and the Earth, so they're very far out there, and 
therefore--and they have little power left although it's a 
radioisotope power. It's a long-lasting power system. They're 
sending back a handful of bits whenever we can turn our big 
telescopes and bring that data back but they're doing a 
marvelous job, really exploring that outer reaches of the 
heliosphere we call it.
    Mr. Webster. What's their wattage?
    Dr. Green. I would only guess but I would believe it's on 
the order of tens of watts. That's all that's left.
    Mr. Webster. And then what would be the final date that it 
won't be able to broadcast anymore? You're saying it's 
diminishing now, right? Is that what you said?
    Dr. Green. Yeah, it uses--utilizes radioisotope, plutonium 
238, which decays over time, and how that works is, you bring a 
mass of plutonium together, it's radioactive. You shield that 
and that radioactive capability where the nucleus of the atom 
blows apart heats and that heats a sleeve that's around this 
material and then that heat through a thermal couple is used to 
charge a battery and then you run your experiments off of it. 
And so over time as the radioisotope decays, then there's 
little heat involved, and now you have major power management 
activities that you have to do, which they're doing to really 
keep the spacecraft going because not only is it providing 
power but it's also providing warmth for the instruments and 
the spacecraft subsystems.
    I can't give you, although I'll take for the record and get 
back to you on exactly what our prediction is when it will 
really have not enough power to sustain itself or it'll be at a 
distance far enough away that we will not be able to track it.
    Mr. Webster. Thank you very much. Yield back.
    Dr. McKinnon. If I could add just one thing to do that, 
that the New Horizons spacecraft, which passed by Pluto and is 
on its way to another body in about a year and a half, will 
also leave the solar system and it's also powered by a similar 
radioisotope heating system and we anticipate that we'll be 
able to contact and operate the spacecraft into the 2030s.
    Chairman Babin. Thank you for those fascinating questions.
    I want to ask one more question. Why do we think that Mars 
lost its atmosphere billions of years ago? And Mars is farther 
away from the sun than Earth, and I'm just going to--Dr. 
Farley, would you take a stab at that?
    Dr. Farley. There may be others here that know more than I 
do about this but this is one of the central purposes of the 
Maven mission, to try to understand why the atmosphere was 
apparently lost, and one of the leading candidates is that the 
planet uses hydrogen, and--to space, and that causes--that 
hydrogen is produced by the breakdown of water, and so you 
break up the water molecule and the hydrogen escapes. You 
cannot re-form the water molecule so that's a way to desiccate 
it by interaction with the solar wind, and one of the jet 
reasons for that is that Mars apparently lost its magnetic 
field very early in its history whereas Earth did not so the 
magnetic field protects the Earth from the radiation from the 
sun that causes this to happen.
    Chairman Babin. Thank you. Anybody else?
    Dr. Elkins-Tanton. Yeah, I'd like to add to that. I've 
worked on that directly. And so this is part of our interest in 
Psyche as a core is to understand the magnetic field, but to 
add to what Ken has said, it's also possible--another 
hypothesis is that when Mars was very young and still hot, its 
atmosphere would have been inflated through heat to be further 
away and less well bound to the body itself, and the more 
active young sun could actually have stripped it at that time. 
And so we don't know exactly when it was stripped or the 
processes, and that's another thing we'd like to learn to find 
out how applicable it is to the Earth.
    Chairman Babin. Great. Those are fascinating answers. Thank 
you so much. I think I'm the only member left here.
    But I want to say how much I appreciate all of you 
fascinating and well-educated scientists for being here, and we 
appreciable your valuable testimony. And also, the record will 
remain open for two weeks for additional comments if any 
Members would like to submit those.
    So with that, this hearing is adjourned. Thank you.
    [Whereupon, at 11:44 a.m., the Subcommittee was adjourned.]

                               Appendix I

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                   Answers to Post-Hearing Questions



                              Appendix II

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                   Additional Material for the Record

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