Planetary Protection Classification
of Sample Return Missions from
the Martian Moons
Committee on Planetary Protection Requirements for
Sample Return Missions from Martian Moons
Space Studies Board
Division on Engineering and Physical Sciences
European Space Sciences Committee
European Science Foundation
A Consensus Study Report of
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This study is based on work supported by Contract NNH17CB02B between the National Academy of Sciences and the National Aeronautics and Space Administration and work supported by Contract 4000118481 between the European Science Foundation and the European Space Agency. Any opinions, findings, conclusions, or recommendations expressed in this publication do not necessarily reflect the views of any organization or agency that provided support for the project.
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Suggested citation: National Academies of Sciences, Engineering, and Medicine and the European Science Foundation. 2019. Planetary Protection Classification of Sample Return Missions from the Martian Moons. Washington, DC: The National Academies Press. doi: https://doi.org/10.17226/25357.
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COMMITTEE ON PLANETARY PROTECTION REQUIREMENTS FOR SAMPLE RETURN MISSIONS FROM MARTIAN MOONS
DAVID PEARCE, Northumbria University, United Kingdom, Chair
ANDRÉ ANTUNES, Edge Hill University, United Kingdom
ATHENA COUSTENIS, LESIA-Observatoire de Paris-Meudon, France
MICHAEL J. DALY, Uniformed Services University of the Health Sciences, United States
ABIGAIL A. FRAEMAN, Jet Propulsion Laboratory, United States
ANSGAR GRESHAKE, Museum für Naturkunde, Germany
GUY LIBOUREL, Observatoire de la Côte d’Azur, France
AKIKO NAKAMURA, Kobe University, Japan
FRANÇOIS POULET, Institute of Space Astrophysics, France
ROBIN PUTZAR, Fraunhofer Institute for High-Speed Dynamics, Germany
KALIAT T. RAMESH, Johns Hopkins University, United States
NORMAN H. SLEEP,1 Stanford University, United States
SHINO SUZUKI, Japan Agency for Marine Earth Science and Technology, Japan
MEGAN BRUCK SYAL, Lawrence Livermore National Laboratory, United States
ERIN L. WALTON, MacEwan University, Canada
EMMANOUIL DETSIS, Science Officer, European Science Foundation
DAVID H. SMITH, Senior Staff Officer, Space Studies Board
MIA BROWN, Research Associate, Space Studies Board
ANDREA REBHOLZ, Program Coordinator, Space Studies Board
JONATHAN LUTZ, Lloyd V. Berkner Space Policy Intern, Space Studies Board
1 Member, National Academy of Sciences.
EUROPEAN SPACE SCIENCES COMMITTEE
ATHENA COUSTENIS, LESIA-Observatoire de Paris-Meudon, France, Chair
CONNY AERTS, Katholieke Universiteit Leuven, Belgium
NABILA AGHANIM, Université Paris-Sud, France
MAHESH ANAND, Open University, United Kingdom
ESTHER ANTONUCCI, Torino Observatory of Astronomy, Italy
SARAH BAATOUT, SCK-CEN, Belgian Nuclear Research Center, Belgium
IAN BROWN, University of Stockholm, Sweden
ALEXANDER CHOUKER, Hospital of the Ludwig Maximilian University, Munich, Germany
BERNDT FEUERBACHER, DLR, Germany
HELEN FRASER, Open University, United Kingdom
MARC HEPPENER, France
ANDREAS KÄÄB, Oslo University, Norway
MAARTEN KROL, Wageningen University, Netherlands
DOMINIQUE LANGEVIN, Université Paris-Sud, France
LUISA LARA, Instituto de Astrofisica de Andalucia, CSIC, Spain
ROSEMARY MORROW, LEGOS, France
HERMANN OPGENOORTH, Swedish Institute of Space Physics, Sweden
GERHARD PAAR, Joanneum Research, Austria
ANNE PAVY-LE-TRAON, University Hospital of Toulouse, France
MICHAEL PERRYMAN, University College Dublin, Ireland
ROBERTO PIAZZA, Milano Politecnico, Italy
MANOLIS PLIONIS, National Observatory of Athens, Greece
PETER PREU, DLR, Germany
PETRA RETTBERG, DLR, Germany
SINDY STERCKX, VITO, Belgium
HUBERTUS THOMAS, DLR, Germany
ALEXANDER TIELENS, Leiden University, Netherlands
STÉPHANE UDRY, University of Geneva, Switzerland
PEPIJN VEEFKIND, Royal Netherlands Meteorological Institute, Netherlands
ROBERT WIMMER-SCHWEINGRUBER, University of Kiel, Germany
JEAN-CLAUDE WORMS, Chief Executive Officer
NICOLAS WALTER, Senior Science Officer
EMMANOUIL DETSIS, Science Officer
CAMELIA STEINMETZ, Administrative Coordinator
SPACE STUDIES BOARD
MARGARET KIVELSON, NAS, University of California, Los Angeles, Chair
JAMES H. CROCKER, NAE,1 Lockheed Martin Space Systems Company (retired), Vice Chair
GREGORY P. ASNER, NAS, Carnegie Institution for Science
JEFF M. BINGHAM, Consultant
ADAM BURROWS, NAS, Princeton University
MARY LYNNE DITTMAR, Dittmar Associates
JEFF DOZIER, University of California, Santa Barbara
JOSEPH FULLER JR., Futron Corporation (retired)
SARAH GIBSON, National Center for Atmospheric Research
VICTORIA HAMILTON, Southwest Research Institute
CHRYSSA KOUVELIOTOU, NAS, George Washington University
DENNIS P. LETTENMAIER, NAE, University of California, Los Angeles
ROSALY M. LOPES, Jet Propulsion Laboratory
STEPHEN J. MACKWELL, American Institute of Physics
DAVID J. McCOMAS, Princeton University
LARRY PAXTON, Johns Hopkins University, Applied Physics Laboratory
ELIOT QUATAERT, University of California, Berkeley
BARBARA SHERWOOD LOLLAR, University of Toronto
HARLAN E. SPENCE, University of New Hampshire
MARK H. THIEMENS, NAS, University of California, San Diego
ERIKA WAGNER, Blue Origin
PAUL WOOSTER, Space Exploration Technologies
EDWARD L. WRIGHT, NAS, University of California, Los Angeles
MICHAEL H. MOLONEY, Director (through March 1, 2018)
RICHARD ROWBERG, Acting Director (March 1 through August 6, 2018)
COLLEEN HARTMAN, Director (beginning August 6, 2018)
CARMELA J. CHAMBERLAIN, Administrative Coordinator (through June 30, 2018)
TANJA PILZAK, Manager, Program Operations
CELESTE A. NAYLOR, Information Management Associate
MARGARET KNEMEYER, Financial Officer
1 Member, National Academy of Engineering.
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COSPAR PLANETARY PROTECTION POLICY FOR THE MARTIAN MOONS
An international consensus policy to prevent the biological cross-contamination of planetary bodies exists and is maintained by the Committee on Space Research (COSPAR) of the International Council for Science, which is consultative to the UN Committee on the Peaceful Uses of Outer Space. Currently, COSPAR’s planetary protection policy does not specify the status of sample return missions from Phobos or Deimos, the moons of Mars. Although the moons themselves are not considered potential habitats for life or of intrinsic relevance to prebiotic chemical evolution, recent studies indicate that a significant amount of material recently ejected from Mars could be present on the surface of Phobos and, to a lesser extent, Deimos. Such interplanetary ejecta might mediate the transfer of viable organisms from one body to another. Such a process is sometimes referred to as lithopanspermia—a variant of the Arrhenius panspermia hypothesis.
Multiple space agencies, including the National Aeronautics and Space Administration (NASA), the European Space Agency (ESA), and the Japan Aerospace Exploration Agency (JAXA), are interested in plans for returning samples of material from the martian moons, which need to receive a planetary protection categorization of either restricted or unrestricted Earth return. A designation of restricted Earth return, per current NASA, ESA, JAXA, and COSPAR policy, would require samples to be maintained in high containment and undergo a biohazard test protocol after return. In addition, the moons of Mars are possible targets for future human exploration. Therefore, an understanding of the potential for life from Mars to persist on Phobos or Deimos is relevant to ensuring astronaut safety on those missions.
NASA and ESA rely on independent scientific advice from, respectively, the National Academies of Sciences, Engineering, and Medicine and the European Science Foundation (ESF) when faced with planetary protection questions not codified in current COSPAR policy. The National Academies and ESF have the ability to synthesize input from a wide spectrum of the scientific and technical communities and provide expert recommendations.
CREATION OF THE JOINT COMMITTEE
To lessen the scientific uncertainties concerning the planetary protection status of the martian moons, NASA and ESA commissioned researchers to perform modeling and experimental activities to assess the extent to which material from Mars might be deposited on the planet’s moons and to assess the post-ejection environmental conditions that might inactivate potential martian life transported to Phobos and Deimos. The tests included
hypervelocity impact sterilization of relevant Earth organisms, as well as the effects of ionizing radiation and heat on martian ejecta.
To provide an independent assessment of the results of these experimental activities, NASA and ESA issued parallel requests in 2016 to the National Academies’ Space Studies Board (SSB) and ESF’s European Space Science Committee (ESSC), respectively (see Appendix A). Both NASA and ESA specifically requested that the National Academies of Sciences, Engineering, and Medicine and the ESF jointly establish an ad hoc committee to review and assess recent research sponsored by NASA and ESA relating to the planetary protection concern that hypothetical martian life might exist on the surfaces of the martian moons, Phobos and Deimos, consequent to their ejection from the surface of Mars following a major impact event. Three specific tasks were enumerated (see the next section, Tasks 1, 2, and 6 in the statement of task).
Although there was no formal Japanese involvement in the commissioning of this study, it was generally agreed by NASA, ESA, the SSB, and ESSC that some participation by independent Japanese scientists was appropriate because of JAXA’s plans to launch the Martian Moons Exploration (MMX) mission in the mid-2020s to collect and return samples from Phobos (or Deimos) to Earth. The joint National Academies-ESF Committee on the Planetary Protection Requirements for Sample Return Missions from the Martian Moons was formally established in mid-October 2017 and held its first and only planned meeting in London on November 6-9, 2017.
In March 2018, while the joint committee was assembling its draft report, NASA (with ESA concurrence) requested that the committee perform three actions (see Appendix B). First, delay the completion of its report. Second, plan to hold an additional meeting in fall 2018 to consider new results from ESA- and JAXA-sponsored groups studying the transfer of material from Mars to its moons. Third, expand the scope of its study by addressing three additional tasks (see Tasks 3 through 5 in the next section).
In fall 2018, five additional members were added to the committee to address the expanded scope of the study, and the committee met again in London on September 18-20, 2018.
The next section details the specific statements for the tasks (1-6) of the committee, in the context of their review of the ESA/NASA/JAXA research work.
STATEMENT OF TASK
The committee was specifically asked to address the following topics:
- Review, in the context of current understanding of conditions relevant to inactivation of carbon-based life, recent theoretical, experimental, and modeling research on the environments and physical conditions encountered by Mars ejecta during the following processes:
- Excavation from the martian surface via crater-forming events;
- While in transit through cismartian space;
- During deposition on Phobos or Deimos; and
- After deposition on Phobos or Deimos.
- Recommend whether missions returning samples from Phobos and/or Deimos should be classified as “restricted” or “unrestricted” Earth return in the framework of the planetary protection policy maintained by the ICSU Committee on Space Research (COSPAR);
- In what specific ways is classification of sample return from Deimos a different case than sample return from Phobos?
- What relevant information for classification of sample return is available from published studies of martian meteorites on Earth?
- What are the planetary protection consequences of taking a surface sample at depths of 0–2 cm versus taking a sample extending down to depths of 2-10 cm or deeper?
- Suggest any other refinements in planetary protection requirements that might be required to accommodate spacecraft missions to and sample returned from Phobos and/or Deimos.
A complete draft of the joint committee’s report was assembled in October 2018 and sent to external reviewers on November 30. Responses to reviewer comments were drafted during the final week of December 2018 and a fully revised draft was approved for public release on January 10, 2019.
The work of the committee was made easier thanks to the important help, advice, and comments provided by numerous individuals from a variety of public and private organizations. These include the following: Allan Bennett (Public Health England), Catharine Conley (NASA), David Evans (Fluid Gravity Engineering Ltd.), Masaki Fujimoto (JAXA), Kazuhisa Fujita (JAXA), Yasuhiro Kawakatsu (JAXA), Gerhard Kminek (ESA), Kosuke Kurosawa (Chiba Institute of Technology), Manish Patel (The Open University), Victoria Pearson (The Open University), Mika Salminen (National Institute for Health and Welfare, Finland), J. Andrew Spry (SETI Institute), Thomas Statler (NASA), David Summers (Thales Alenia Space), Peter Triscott (Kallisto Consultancy), and Akihiko Yamagishi (Tokyo University of Pharmacy and Life Sciences). The committee offers special thanks to Kai Finster (Aarhus University) for his services as a consultant and participant in its first meeting.
The European Science Foundation elected not to conduct an independent review of this report. Rather, they agreed to abide by the report review policies and practices used by the National Academies. Therefore, this Consensus Study Report has been reviewed in draft form by individuals chosen for their diverse perspectives and technical expertise. The purpose of this independent review is to provide candid and critical comments that will assist the National Academies in making each published report as sound as possible and to ensure that the report meets the institutional standards for objectivity, evidence, and responsiveness to the study charge. The review comments and draft manuscript remain confidential to protect the integrity of the deliberative process.
We thank the following individuals for their review of this report: Kathrin Altwegg (University of Bern); Donna Blackmond, NAE (Scripps Research Institute); John Bridges (University of New Brunswick); Charles Cockell (University of Edinburgh); Gareth Collins (Imperial College); Dennis Discher, NAE, NAM (University of Pennsylvania); Katherine H. Freeman, NAS (Pennsylvania State University); Stephen Mackwell (American Institute of Physics); Ajay Malshe, NAE (University of Arkansas); John Spray (University of Leicester); and Erika Wagner (Blue Origin).
Although the reviewers listed above have provided many constructive comments and suggestions, they were not asked to endorse the conclusions or recommendations of this report nor did they see the final draft before its release. The review of this report was overseen by Steven J. Battel, NAE (Battel Engineering, Inc.). He was responsible for making certain that an independent examination of this report was carried out in accordance with the standards of the National Academies and that all review comments were carefully considered. Responsibility for the final content rests entirely with the authoring committee and the National Academies.
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The Martian Moons: Phobos and Deimos
Earth Inventory of Martian Meteorites
Future Missions to the Martian Moons: The MMX Mission
Planetary Protection and COSPAR Policy
Studies in Support of Planetary Protection Classification of Martian Moons Sample Return
2 OVERVIEW AND ASSESSMENT OF THE STERLIM AND JAXA STUDIES
Potential Microbial Density on the Martian Surface
Mars Ejecta Formation and Transportation from the Martian Surface
Sterilization During Mars Ejecta Formation
Sterilization by Aerodynamic Heating of Mars Ejecta
Sterilization During Hypervelocity Impact on Phobos/Deimos Surfaces
Distribution of Mars Ejecta Fragments by Impacts, Recirculation, and Reimpact
Sterilization by Radiation on Phobos/Deimos Surfaces
Phobos/Deimos Surface Reformation by Natural Meteoroid Impacts
3 RESPONSES TO THE STATEMENT OF TASK AND RECOMMENDATIONS
Task 1—Review of Current Understanding
Task 2—Restricted or Unrestricted Earth Return for Martian Moons Sample Return Missions
Task 3—Differences Between Phobos and Deimos in the Context of Planetary Protection
Task 4—Relevant Information from Studies of Martian Meteorites
Task 5—Planetary Protection Consequences of Sampling at Depth
Task 6—Other Refinements to Planetary Protection for Martian Moons Sample Return