Planetary protection, as practiced by NASA and other national and international space agencies for the past 70 years, has two rationales: “to protect the biological and environmental integrity of other solar system bodies for future science missions” and “to preserve the integrity of Earth’s biosphere.”1 A more recent statement from the Committee on Space Research’s (COSPAR’s) Panel on Planetary Protection (PPP) contains a somewhat longer, but equivalent, pair of rationales. First, “the conduct of scientific investigations of possible extraterrestrial life forms, precursors, and remnants must not be jeopardized.” Second, “the Earth must be protected from the potential hazard posed by extraterrestrial matter carried by a spacecraft returning from another planet.”2
In 1958, a subcommittee of the International Council of Scientific Unions3 issued the first code-of-conduct for planetary quarantine (as the topic was then called) and recommended that the recently established COSPAR assume responsibility for deliberating on matters of planetary protection.4 The 1967 Outer Space Treaty formalized the international legal requirements for states parties to avoid “harmful contamination” of celestial bodies and “adverse changes in the environment of the Earth.” COSPAR guidelines have evolved in response to new scientific and technical developments, and all major space-faring nations have adopted these guidelines in connection with their exploration and study of solar system bodies.5
Tensions developed in the earliest years of the Space Age between the space science and engineering communities concerning the need for and implementation cost of planetary protection policies.6 According to one per-
1 National Academies of Sciences, Engineering, and Medicine (NASEM), Review and Assessment of Planetary Protection Policy Development Processes, The National Academies Press, Washington, D.C., 2018, p. 9.
2 A. Coustenis, G. Kminek, N. Headman, E. Ammannito, E. Deshevaya, et al., “The COSPAR Panel on Planetary Protection Role, Structure and Activities,” Space Research Today, Number 205, 2019, pp. 14-26.
3 This organization later changed its name to the International Council for Science, but retained its original acronym, ICSU. In 2018, ICSU merged with the International Social Science Council to create the International Science Council.
5 G. Kminek, C. Conley, V. Hipkin, H. Yano, “COSPAR’s Planetary Protection Policy,” Space Research Today, Number 200, December 2017, https://cosparhq.cnes.fr/assets/uploads/2019/12/PPPolicyDecember-2017.pdf.
6 M. Meltzer, When Biospheres Collide: A History of NASA’s Planetary Protection Programs, NASA SP-2011-4234, NASA History Program Office, Washington, D.C., 2011, pp. 46-51.
spective, planetary protection policies represent a prudent balance between humanity’s desire to explore the solar system in a responsible manner and avoid risks that could, potentially, preclude future investigations. Accordingly, exploration conducted in an irresponsible manner could have consequences ranging in scope from the introduction of false positives in life-detection experiments—caused by organisms inadvertently transferred from Earth—to low-probability, high-consequence events arising from the introduction of a replicating extraterrestrial entity into Earth’s environment. A different perspective holds that current planetary protection policies are outmoded, based on scientific speculations and extrapolations, costly to implement, and impede scientific studies and other activities in planetary environments. As we shall see, new issues concerning the development of planetary protection policies and their implementation have arisen in recent years.
The advent of new space activities and new players in the exploration and use of space have again put a spotlight on the already complicated planetary protection landscape. These new developments include the following:
- National and international space agencies are working with the worldwide science community to develop robotic missions to collect martian samples and bring them to Earth, thus raising the possibility, however unlikely, of potential harm to the biosphere supporting all life on Earth.
- Space agencies are also planning to dispatch missions to explore the so-called ocean worlds—those astrobiologically important satellites of the giant planets—for example, Europa, Enceladus, and Titan—possessing large quantities of liquid water beneath their icy surfaces.7 The physical conditions in such oceans are believed to be similar to those found in Earth’s deep oceans. In contrast, terrestrial organisms exposed on the martian surface will likely not survive prolonged exposure to the ambient ultraviolet radiation and oxidizing chemical species on Mars. The global nature of such subsurface oceans means that terrestrial biological contamination would likely not remain localized if it reached the ocean.
- Burgeoning interest in the return of astronauts to the Moon and their eventual voyages to Mars is creating planetary protection issues. Human missions to the Moon raise some planetary protection concerns, especially in connection with in situ resource utilization for supporting the human presence on the Moon (e.g., the potential for the contamination or depletion of polar ice deposits and thus a loss of scientific information about the history of the flux of volatile materials over the history of the inner solar system). However, sending astronauts to Mars raises far more serious planetary protection issues because the policies and procedures developed for robotic missions to Mars are incompatible with human health, safety, and activities on Mars.
- The rapid evolution in the number and sophistication of private-sector space companies and activities is presenting new challenges for planetary protection policy. First, current policies focus almost exclusively on government-led, scientific, and robotic spacecraft missions. New types of private-sector space activities offer a potentially more diverse set of missions. Second, past private-sector space activities conducted without NASA involvement, such as launching and operating satellites, did not implicate planetary protection, which means that private-sector actors did not participate in the processes used to develop planetary protection policy. Thus, with the advent of private-sector space activities that create planetary protection questions, integrating private-sector input into these policy development processes has become necessary.
The convergence of these various concerns produced a number of important actions. First, NASA commissioned a study by the National Academies of Sciences, Engineering, and Medicine to examine planetary protection policy development processes. Second, COSPAR reformed and reorganized its Panel on Planetary Protection, and NASA made major changes in its Office of Planetary Protection. Third, NASA established the Planetary Protection Independent Review Board (PPIRB) to provide more input on the challenges facing planetary protection policy in the future. The next three sections summarize these actions. This committee’s statement of task (see Preface and Appendix A) encompasses the study from the National Academies and the PPIRB’s input, so these actions are examined more closely below.
7 For more about ocean worlds see, for example, A.R. Hendrix, T.A. Hurford, L.M. Barge, M.T. Bland, J.S. Bowman, et al., The NASA roadmap to ocean worlds, Astrobiology 19:1-27, 2019.
In response to the evolving planetary protection landscape, NASA’s Science Mission Directorate (SMD) requested in February 2016 that the Space Studies Board (SSB) study the current process by which planetary protection policy is developed and recommend actions or options for NASA. Subsequent discussions between the SSB and NASA resulted in the formulation and adoption of the following statement of task for the study:
The National Academies of Sciences, Engineering, and Medicine will appoint an ad hoc committee to carry out a study that will describe how international and national planetary protection policy has been formulated and adopted and identify associated lessons to inform future policy development. Specifically, the committee will assess the current state of planetary protection policy development, and the extent to which the current policy-making process is responsive to the present state of science, technology, and engineering, including biological science, as well as the exploration interests of state and nonstate actors. The committee’s review will lead to recommendations on how to assure the planetary protection policy process is supportive of future scientific and societal interests, as well as spaceflight missions.
It is suggested that the committee organize its review around three themes:
- Historical context and the current policy development process, including a working definition of planetary protection and its goals;
- Key factors in the current policy development process; and
- The future of the policy development process.
In response to NASA’s request, the SSB established the Committee on the Review of Planetary Protection Policy Development Processes. The committee began its work in March 2017, and issued its report, Review and Assessment of Planetary Protection Policy Development Processes8 (hereafter the “2018 report”), in June 2018. This report did not address the substance of planetary protection policies, the specific requirements flowing from those policies, or the mission-level methodologies and techniques for implementing the requirements. It concerned itself exclusively with the processes that developed planetary protection policy. The 130-plus page report contained 27 findings and 17 recommendations (reprinted in Appendix B).
In its analysis, the 2018 report identified a number of fundamental aspects of the planetary protection policy development process that remain relevant and vital today, including the following:
- The Outer Space Treaty as the policy and legal foundation for both government-sponsored and nongovernmental space activities;
- COSPAR’s role in fostering international cooperation on planetary protection guidelines;
- The centrality of science-based decision making;
- The involvement of many scientific communities; and
- U.S. leadership in planetary protection policy making.
The report also found that NASA needs to address the following issues:
- Managing policy implementation;
- Securing cutting-edge, outside expert advice for NASA;
- Developing a long-range forecast of future solar system exploration missions having planetary protection implications;
- Setting planetary protection research and technology investment priorities; and
- Creating plans for dealing with major policy issues, such as Mars sample-return, human missions to Mars, and private-sector space activities.
8 NASEM, 2018.
The 2018 report recommended that NASA develop a strategic plan for planetary protection that responds to each of the aforementioned priority issues.
With respect to private-sector activities, the 2018 report reached the following conclusions:
- Planetary protection policy applies to missions to all solar system bodies; however, only missions to those objects that may be likely to support life require substantial planetary protection actions (meaning, for the near term, missions to Mars, Europa, and Enceladus);
- Planetary protection policies and requirements for forward and back contamination apply equally to government-sponsored and private-sector missions; and
- A “regulatory gap” exists in U.S. federal law governing private-sector activities in space that poses a problem for U.S. compliance with the mandate in Article VI of the Outer Space Treaty that states parties authorize and continually supervise the space activities of nongovernmental entities.
In response to private-sector input, the report recommended that NASA ensure that its policy-development processes, including advisory mechanisms, make appropriate efforts to incorporate the views of the private sector. Moreover, the report encouraged COSPAR to support efforts to increase private-sector participation in the organization’s planetary protection activities.
With respect to the “regulatory gap,” the report recommended that Congress promulgate legislation that grants jurisdiction to an appropriate federal regulatory agency to authorize and supervise private-sector space activities that raise planetary protection issues. Moreover, the enactment of such legislation would ensure that the authority granted be exercised in a way that is based on the most relevant scientific information and best practices on planetary protection.
The National Academies’ 2018 report was conducted while two key players in planetary protection underwent significant changes. For decades, NASA’s Office of Planetary Protection (OPP) was located in the agency’s Science Mission Directorate (and its predecessor organizations).9 The 2018 report noted that this placement created “an inherent conflict of interest because the dispute resolution official was directly responsible for science missions as well as planetary protection.”10 Moving OPP to the Office of Safety and Mission Assurance (OSMA) would allow OPP to “function more like a NASA technical authority and disagreements between the OPP and flight projects on planetary protection issues can be resolved through formal OSMA conflict resolution procedures that have worked well in other areas within OSMA’s purview.”11
One concern the 2018 report raised about moving OPP from SMD to OSMA focused on the small planetary protection research program (see Figure 3.1), a component of NASA’s annual Research Opportunities in Space and Earth Science (ROSES) call for research and analysis proposals. SMD, the home of ROSES, provided a more appropriate environment for the planetary protection research than OSMA, which does not run research programs. For this reason, NASA kept the planetary protection research program in SMD and hired a new program manager.
In addition, COSPAR was reorganizing its PPP while the 2018 report was in progress. Prior to the summer of 2018, the PPP consisted of a chair and one or more vice chairs—typically planetary-protection practitioners—appointed by the president of COSPAR for a 4-year term. The remainder of the participants in the PPP’s activities were those individuals who attended PPP-organized events at COSPAR scientific assemblies and other venues—mainly planetary-protection experts and planetary scientists and astrobiologists. This informal structure suggested
9 For much of this period, the OPP and its one permanent staff member, the NASA planetary protection officer (PPO), were virtually synonymous.
10 See NASEM, 2018, p. 60.
11 See NASEM, 2018, p. 60.
to COSPAR’s leaders that the manner in which the PPP operated did not reflect the important role COSPAR played in developing international scientific consensus on planetary protection guidelines.12
COSPAR initiated reforms to formalize the linkages between the PPP, national space agencies, and the UN Committee on the Peaceful Uses of Outer Space (COPUOS). These reforms included actions in five areas. First, the PPP chair would not be a planetary-protection expert but, rather, a senior scientist active in the robotic exploration of the solar system. Second, the PPP would have two vice chairs, one nominated by the UN Office of Outer Space Affairs and the other drawn from the planetary protection community. Third, national space agencies would formally nominate individuals to serve as members on the PPP. Fourth, COSPAR’s Scientific Commission B (planetary science) and Commission F (space life sciences) would nominate scientists from the planetary science and biological communities to be PPP members. Fifth, the PPP would meet regularly and not just during COSPAR’s scientific assemblies. PPP meetings would still be open to all interested participants, but the panel’s decision-making process would involve only appointed members.13
COSPAR implemented the reforms during its 2018 scientific assembly, and the PPP has, as of this writing, held two meetings in its reconstituted form. At its January 2019 meeting—held at the United Nations Center in Vienna, Austria—the panel discussed and reached consensus on two major items.14 First, in response to input from the Japan Aerospace Exploration Agency (JAXA), a consortium supported by the European Space Agency, and the National Academies, the PPP proposed recommendations on the categorization of samples of Phobos or Diemos to be returned to Earth by JAXA’s Martian Moons Exploration spacecraft.15 Second, based on input from an international consortium organized by the European Science Foundation, the PPP made recommendations on planetary protection issues for missions to the icy satellites of the giant planets. At its March 2019 meeting, the COSPAR Bureau approved PPP’s recommendations on these two topics. PPP’s second meeting after its reorganization took place in December 2019, also in Vienna, and, among other things, the PPIRB briefed the PPP on its report, and the PPP discussed the report’s implications.
On November 15, 2018, NASA Administrator James Bridenstine approved the terms of reference of the NASA Advisory Council’s (NAC’s) new Regulatory and Policy Committee (RPC). The scope of the RPC “includes advising on NASA-related civil space regulation and policy, broadly defined, including but not limited to regulation, legislation, and interagency and international governance issues, to catalyze America’s civil space economy and advance other policy objectives.” One of the items on RPC’s agenda during its first meeting (held on November 16, 2018) was COSPAR and, in particular, its role in planetary protection policy. The RPC adopted two findings and two recommendations on the COSPAR agenda item (see Appendix D). The NAC addressed the RPC’s findings and recommendations at its December 10-11, 2018, meeting. The NAC issued a recommendation stating, in part, that “NASA should establish a multi-disciplinary task force of experts from industry, the scientific community, and relevant government agencies, to develop U.S. policies that properly balance the legitimate need to protect against the harmful contamination of the Earth or other celestial bodies with the scientific, social, and economic benefits of public and private space missions” (see Appendix D). Moreover, the NAC stated that, if “NASA adopts the COSPAR guidelines without any review or revision they will have a chilling effect on robotic, human spaceflight, and private-sector missions.”
Prompted by the NAC’s recommendation, NASA issued the following response:
12 See NASEM, 2018, pp. 72-74.
13 For more details about the reorganization of the PPP, see A. Coustenis, G. Kminek, N. Hedman, E. Ammannito, E. Deshevaya, et al., “The COSPAR Panel on Planetary Protection: Role, Structure and Activities,” Space Research Today, Number 205, August 2019, https://cosparhq.cnes.fr/assets/uploads/2019/07/PPP_SRT-Article_Role-Structure_Aug-2019.pdf.
14Space Research Today, Number 205, August 2019, pp. 23-24.
15 NASEM and European Science Foundation, Planetary Protection Classification of Sample Return Missions from the Martian Moons, The National Academies Press, Washington, D.C., 2019.
NASA concurs with the recommendation. The NASA Science Mission Directorate (SMD) currently is establishing a Planetary Protection Independent Review Board, of approximately 10-15 members and short-term in nature, to assess and provide updates to biological contamination guidelines developed by the international Committee on Space Research (COSPAR). The Planetary Protection Independent Review Board’s assessment will include analysis of the scientific, engineering, industrial, legal, and program management aspects of planetary protection. Results of the assessment will be documented in a non-consensus final report presentation, and the Independent Review Board will brief NASA, NASA advisory committees, and external stakeholders as appropriate.16
The PPIRB held an organizing conference call in late June 2019 and its first face-to-face meeting at NASA Headquarters on July 10-11 (see Appendix D). It held multiple meetings in the summer of 2019 and issued its report, NASA Planetary Protection Independent Review Board (PPIRB): Report to NASA/SMD: Final Report17 (hereafter the “PPIRB report”), in September 2019.
The PPIRB report reflected the input by experts from many scientific disciplines, policy communities, and private-sector enterprises that the board commendably compiled into its report in a very brief period of time in order to meet the deadline set by NASA. Generally, the PPIRB provided little or no supporting evidence, information, or narrative explanations for most of its findings and recommendations.18 The lack of supporting evidence, information, or explanatory text makes the basis and reasoning behind many findings and recommendations difficult to understand and assess. The committee appreciates the efforts the chair of the PPIRB, S. Alan Stern, made to help the committee review the PPIRB report and compare it with the 2018 report.
Chapter 2 contains the committee’s point-by-point comparison of the PPIRB report’s findings and recommendations with the 2018 report. The committee notes that, strictly speaking, its statement of task calls for it to “review the findings” of the PPIRB report and “comment on their consistency with the recommendations” of the 2018 report.19 For obvious reasons, the committee has interpreted its charge to mean that it review the findings and recommendations of the PPIRB report for consistency with the findings and recommendations of the 2018 report. The committee also notes that the PPIRB report’s thematic organization means that some topics appear more than once. As a result, the committee’s point-by-point assessment of the PPIRB’s findings and recommendations in Chapter 2 contains some necessary repetition.
Chapter 3 summarizes those areas of consistency and inconsistency between the two reports. The chapter also identifies a number of issues covered in the PPIRB report but not discussed in the 2018 report because those issues were beyond the 2018 report’s statement of task or involve events transpiring after the 2018 report was completed. Then Chapter 3 discusses, and makes recommendations to address, three challenges that the two reports identify as priorities for NASA. The committee concludes with recommendations concerning ways that NASA can expedite the development of a new approach to planetary protection policy through a focus on addressing planetary protection challenges faced by public and private actors interested in small,20 low-cost spacecraft.
16 Planetary Protection Independent Review Board (PPIRB), NASA Planetary Protection Independent Review Board (PPIRB): Report to NASA/SMD: Final Report, NASA, Washington, D.C., 2019, https://www.nasa.gov/sites/default/files/atoms/files/planetary_protection_board_report_20191018.pdf, Appendix C.
17 See PPIRB, 2019.
18 The PPIRB report’s findings and recommendations vary in length from a single sentence to a paragraph, with 25 items listed as findings or recommendations incorporating a sentence or two of explanatory text. See PPIRB, 2019 [5, 6, 30, 36, 37, 39, 41, 43, 45, 46, 47, 48, 51, 54, 58, 60, 61, 62, 64, 68, 69, 71, 72, 74, 75]. Only five of the findings and recommendations contain references to supporting information or evidence. See PPIRB, 2019  (one reference),  (four references),  (two references),  (two references), and  (two references). In sum, 52 of the 77 total findings and recommendations lack supporting evidence, information, or explanatory text.
20 The committee defines a small spacecraft as one with a mass of less than 600 kg.