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Introduction

From the beginning of the space age, scientific goals have powerfully shaped solar system exploration. Missions have been focused on research to understand the origin and evolution of solar system bodies and discover evidence of extant or relic life. Two seminal questions formulated by the original NASA astrobiology program definition in 1995 were Where did we come from? And Are we alone? Those profound questions have captivated the public and yielded congressional support for NASA’s programs, including its orbiting, in situ, and sample return missions that have the best prospects of locating and detecting extinct or extant life in the solar systm.

Liquid water is necessary for all life as we know it, so finding present or past existence of water is critical in the search for extraterrestrial life. The science community accepts that Mars, at one time, had large amounts of liquid water on the surface. Much of the remaining water is locked into ice at or near the surface, and liquid water may still be present underground. Similarly, the so-called Ocean Worlds (i.e., a subset the icy bodies of the outer solar system)—especially Jupiter’s Europa and Saturn’s Enceladus—have abundant liquid water beneath surface ice shells. Saturn’s Titan also has a deep subsurface liquid water ocean. Moreover, that ocean is potentially in contact with the moon’s surface, which is itself a veritable laboratory for prebiotic chemistry with lakes and rivers of methane and ethane. In addition, Jupiter’s Ganymede, and even Callisto, may have water deep under their icy surfaces.

NASA’s next two major strategic science missions that have significance for both life detection and planetary protection are Mars 2020 (potentially the first phase of a sample return campaign) and the Europa Clipper. Other mission concepts for the exploration of the Ocean Worlds have been and are being studied.¹ As complicated as those science missions will prove to be, the character of solar system use and exploration is on the verge of a dramatic change.

Planning for Mars sample return brings much greater challenges to not only science and engineering but also planetary protection. Except for the return of lunar material during the Apollo program and the benign samples of a comet (Stardust mission), the solar wind (Genesis mission), and asteroids (Hayabusa 1, Hayabusa 2, and OSIRIS-REx mission), planetary protection policy has not had to address the complex issues associated with the return of samples of extraterrestrial material. Especially for sample return missions, the need to develop better and more complete planetary protection policies is becoming urgent, given the pressing timelines of mission planning

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¹ These include, but are not limited to, the Titan Mare Explorer (http://www.astro.cornell.edu/academics/courses/astro2202/TiME_06497165.pdf), the Enceladus Habitability and Life Signature, Europa lander (https://europa.nasa.gov/resources/58/europa-lander-study-2016-report), and Dragonfly (http://dragonfly.jhuapl.edu).

and design. Human exploration of Mars will involve potential contamination challenges that planetary protection policy also has not needed to manage in the past.

The space agencies of other nations, including India and the European Space Agency (ESA), have sent orbiters to Mars, and others, such as the China and the United Arab Emirates, are preparing for similar missions for launch in the near future. Further, NASA is planning human missions to Mars in future decades. Exploration of Mars might also generate interest from private-sector entities that want to undertake their own missions or provide goods and services to NASA in activities related to Mars.² Very recently, one company, SpaceX, conducted its own private test launch of a new vehicle, the Falcon 9 Heavy, with a dummy payload that was propelled into an Earth-escape trajectory. While the Federal Aviation Administration did indeed approve the launch, only very recently—i.e., after the public release of the prepublication version of this report—has it been become clear that formal, but limited, consultations on the planetary protection implications of this test flight took place between NASA, the Federal Aviation Administration, and SpaceX.

While science continues to be a fundamental rationale for the robotic exploration of all parts of the solar system, other motivations are emerging in deep-space activities. Those drivers, some of which are mentioned above, may be characterized in the following three categories:

• Traditional government agencies, especially NASA, seek to pursue broader geopolitical and technological objectives embodied in human exploration missions to Mars;
• New governmental entrants seek to join the community of space-faring nations via robotic and perhaps human missions to the Moon and eventually to Mars; and
• Private-sector entities seek to both provide commercial transportation to the Moon and Mars and also leverage past scientific findings for commercial benefits, including lunar missions and asteroid mining.³

This future transformative context for solar system exploration has implications for planetary protection policy development and implementation. The involvement of more governments and, potentially, the private sector introduces new players, priorities, and opportunities for using and advancing science and technology. Efforts to establish a human presence on Mars also will profoundly affect the historical and internationally well-accepted objectives of avoiding harmful contamination of other planetary bodies.

Past planetary protection policies have exclusively applied to government-sponsored missions by a small number of countries because only governments undertook space exploration that required consideration of planetary protection. In the United States, NASA’s requirements have sufficed for these missions. However, as noted above, both governments and the private sector are beginning to consider missions that could expand the nature and scales of activity. An arena that was formerly the exclusive purview of a few space-faring countries (notably the United States, Russia, Japan, and various European nations) is expanding. NASA, the federal government, and the international community do not yet have planetary protection policy development processes in place that are ready to respond to expansion in the number of actors and types of activities.

Furthermore, while past planetary protection policies have focused primarily on meeting international scientific objectives, some future missions can be expected to stimulate growing public interest, and even concerns. Increasingly promising prospects for searching for evidence of the origin and existence of life elsewhere in the solar system and the approaching reality of robotic and crewed collection of samples from Mars will increase public interest in how space missions will be prepared to meet the dual objectives of planetary protection (see the below section, “Interim Report”).

This report addresses the implications of changes in the complexion of solar system exploration as they apply to the process of developing planetary protection policy. In particular, it responds to a request from NASA to examine the history of planetary protection policy, assess the current policy development process, and recom-

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² See, for example, E. Musk, Making humans a multi-planetary species, New Space 5:46-61, 2017; and E. Musk, Making life multi-planetary, New Space 6:2-11, 2018.

³ At least one private-sector entity is planning robotic and human missions to orbit and/or land on Mars. For details see, for example, E. Musk, Making humans a multi-planetary species, New Space 5:46-61, 2017; and E. Musk, Making life multi-planetary, New Space 6:2-11, 2018.

mend improvements to make the process more responsive to present and future needs. (See Preface for the full statement of task.)

SCOPE OF THIS STUDY

In response to NASA’s request, the National Academies established the Committee to Review the Planetary Protection Policy Development Processes (hereinafter referred to as “the committee”), operating under auspices of the Space Studies Board. (See Appendix F for committee member biographies.) This report presents the results of the committee’s reviews and deliberations. The committee considered planetary protection policy development from the perspective of all types of missions—including government-sponsored and private-sector efforts having either scientific or commercial objectives and utilizing either robotic or human-crewed spacecraft.

In its broadest sense, planetary protection policy addresses missions to and from all types of solar system bodies, including the Moon, planets, small bodies (such as comets and asteroids), and the satellites of other planets. Current policy places these targets into categories based on the type of mission, the likelihood that a body may be able to harbor life, and the probability that terrestrial organisms might survive on that body or that material returned to Earth might pose a risk to the terrestrial biosphere.

Based on existing knowledge and capabilities, only three objects create serious planetary protection concerns: Mars, Europa, and Enceladus. For Mars, there is very strong evidence of past abundant water on the surface, and measurements indicate a past habitable environment where life may have formed and could potentially survive today in some subsurface refugia. Massive amounts of near surface water ice have been verified at Mars. Missions that have examined Europa and Enceladus indicate the presence of internal liquid water in contact with a rocky core that, therefore, might support indigenous life forms.⁴ Within this set of bodies, current and anticipated plans for private-sector activities only involve missions to Mars.⁵ Because the Moon and most asteroids are, in general, considered of low priority for studies of life and/or prebiotic chemistry, those bodies pose few planetary protection challenges for government-sponsored or private-sector missions, and no planetary protection requirements are imposed beyond the preparation, review, and approval of brief documentation.

The committee’s charge focused on the process by which planetary protection policy is formulated. The charge did not ask the committee to propose specific policies or to assess specific standards, procedures, or validation methods through which space missions execute planetary protection policies. However, the committee found it necessary to consider implementation when the policy development process impacts the translation of policies into implementation roles and responsibilities. The committee also examined specific examples of how implementation requirements have been levied when the cases help illuminate strengths or weaknesses of the policy development process. Further in response to its charge, the committee considered topics related to research and technology development in terms of how it might be needed to support policy development in the future.

INTERIM REPORT

NASA’s charge to the committee included a request for an interim report that addressed the rationales for and goals of planetary protection and that suggested a working definition of planetary protection. NASA asked for the interim report to be completed shortly after the committee’s first meeting, so the interim report focused

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⁴ There is evidence for liquid water oceans under the thick crusts of, for example, Jupiter’s moons Ganymede and Callisto. However, these oceans are sandwiched between upper and lower layers of ice. Such a configuration is less interesting than that found at Europa and Enceladus from an astrobiological perspective because there is no contact between liquid water and the satellites silicate core. Saturn’s Titan has hydrocarbon lakes, a complex “hydrological” cycle based on methane and ethane, so the greatest current planetary protection concern would be for compromising studies related to prebiotic organic chemistry. For more on the possibility of living systems based on liquid hydrocarbons see, for example, National Research Council, The Limits of Organic Life in Planetary Systems, The National Academies Press, Washington, D.C., 2007, pp. 69-78.

⁵ A presentation by S.P. Worden to the Committee on an Astrobiology Science Strategy for the Search for Life in the Universe on April 25, 2018, indicated that the Breakthrough Foundation was in advanced discussions with NASA to initiate a project to send “chipsats” to Europa and/or Enceladus. For details, see http://sites.nationalacademies.org/SSB/CurrentProjects/SSB_180812.

exclusively on planetary protection as it applied to robotic, scientific missions undertaken by the U.S. government. The committee delivered its interim report to NASA on June 7, 2017.⁶ Consideration of broader aspects of planetary protection, including private-sector and human missions and implications for implementation roles and responsibilities, were deferred until this final report.

The interim report adopted the same two goals for planetary protection that NASA, international, and Space Studies Board documents have reflected for decades:

1. The control of forward contamination, defined by NASA as “the control of terrestrial microbial contamination associated with robotic space vehicles intended to land, orbit, flyby, or otherwise encounter extraterrestrial solar system bodies”;⁷ and
2. The control of back contamination, defined by NASA as “the control of contamination of the Earth and the Moon by extraterrestrial material collected and returned by robotic missions.”⁸

The interim report then identified two related rationales for planetary protection, in priority order:

1. Preserve the integrity of Earth’s biosphere; and
2. Protect the biological and environmental integrity of other solar system bodies for future science missions.⁹

As made clear in the interim report, the first rationale encompasses human safety because it is an integral component of the interdependent survival of human, animal, and plant species inhabiting planet Earth.

With respect to the development and implementation of planetary protection policy, the committee emphasizes that the fundamental goal of such policy is to enable, not inhibit, exploration and the search for life.

The interim report also discussed whether planetary protection might involve a third rationale focused on avoiding false results in searching for evidence for life in in situ or returned samples. After further discussion, the committee concluded that there is no need to identify a third rationale.

Avoiding false results in searching for evidence of life is important for the science investigations and the implementation of planetary protection policies. In principle, a false-negative might expose the terrestrial environment to possibly harmful organisms. A false-positive might inhibit distribution of safe samples for analysis by the broad scientific community. Over the longer term, false negative results could expose future exploration missions—including human missions—to overlooked hazards, while false positive results could unjustifiably curtail any immediate or future scientific activities.

The process to develop planetary protection policies has a legitimate interest in ensuring that space missions satisfy requirements, including contamination and cleanliness requirements, connected to the integrity of scientific investigations. Meeting such requirements minimizes the ambiguity of scientific measurements and their interpretation concerning examination of both in situ and returned samples of extraterrestrial matter. However, science mission teams, not those responsible for planetary protection policy, have always established the requirements for the integrity and quality of scientific investigations, subject to peer review, satisfaction of planetary protection directives, and management oversight. The appropriate use of peer review will ensure the validity of all scientific findings used to influence new planetary protection policies or practices from both government-sponsored and

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⁶ National Academies of Sciences, Engineering, and Medicine (NASEM), The Goals, Rationales, and Definition of Planetary Protection: Interim Report, The National Academies Press, Washington, D.C., 2017.

⁷ As will become clear later, neither Article IX of the Outer Space Treaty nor the consensus international planetary protection policy maintained by the Committee on Space Research (COSPAR) of the International Council for Science (ICSU) makes a distinction between robotic and human space flight.

⁸ NASA, Planetary Protection Provisions for Robotic Extraterrestrial Missions, NASA Interim Directive 8020.109A, March 30, 2017.

⁹ The interim report referred to protection of other solar system bodies “in their natural state.” That language does not appear in prior COSPAR or NASA documents. In order to avoid implying that the committee intends to broaden planetary protection policy beyond issues regarding protecting scientific searches for evidence of life, the committee has removed the phrase from its statement of rationale 2 in this final report. Whether planetary protection policies expand beyond their traditional focus on biological/organic contamination has been raised in ethical discussions of planetary protection. See the section “Ethical Considerations” below.

private-sector missions. For this reason, the committee concludes, as it argued in the interim report,¹⁰ that the two traditional rationales for planetary protection policy already address the need for planetary protection officers to ensure that space missions satisfy the requirements for the integrity of scientific investigations established by the science mission team.

Altogether, in the committee’s judgment, the voice of the planetary protection office, shaped with appropriate expert consultation, is presumed to be authoritative, but not dispositive, on matters that derive directly from the two rationales for planetary protection identified above, and all the more so in matters pertaining to the safety and integrity of Earth’s biosphere. However, the committee does not believe there are substantive arguments to augment these two rationales—that is, preserve the integrity of Earth’s biosphere and protecting integrity of other solar system for future studies—with a third one focused on the integrity of the science investigations themselves.

Finding: The committee finds no reason to augment these two established rationales for planetary protection with a third one focused on the integrity of the science investigations themselves.

As part of the conflict resolution process (discussed in Chapter 3), matters of broader programmatic significance, including cost, risk, and overall program objectives as well as planetary protection, may be brought to bear for ultimate judgement and decision, at the level of an associate administrator or higher if needed. For example, a false-positive result concerning a sample return from Mars could compromise biological study of the returned material. This situation would not, by itself, constitute a hazard to Earth or Mars in planetary protection terms. The potentially compromised sample could remain in confinement on Earth, and the false-positive result could lead to restrictions on any future activities on Mars. Neither of these outcomes is good for space exploration, but the consequences of false positive results requires assessment by NASA officials responsible for the overall success and effectiveness of NASA science and exploration programs. False positives would likely have international repercussions because they would impact all missions to the relevant body (e.g., Mars), not just those launched by NASA.

The interim report’s second task was to provide a working definition of planetary protection. Taking into consideration U.S. obligations under the Outer Space Treaty (OST) and current planetary protection approaches as developed by NASA and the Committee on Space Research (COSPAR) (see Chapters 2 and 3),¹¹ the committee adopted the following definition:

This definition encompasses a wide range of activities that contribute to effective policy. For example, implementation involves translating policy into planetary protection goals and requirements for specific missions, as well as validation of compliance with requirements. New scientific findings and technological advances inform both policy formulation and implementation about how to make the planetary protection actions more effective in future space exploration activities. Policy formulation occurs at both national and international levels, and in the case of internationally cooperative missions, all of these steps have international implications.

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¹⁰ NASEM, The Goals, Rationales, and Definition of Planetary Protection: Interim Report, The National Academies Press, Washington, D.C., 2017, pp. 8-10.

¹¹ COSPAR is a scientific organization established by the International Council for Science (ICSU) in 1958 “to promote at an international level scientific research in space, with emphasis on the exchange of results, information and opinions, and to provide a forum, open to all scientists, for the discussion of problems that may affect scientific space research. The objectives of COSPAR are to be achieved through the organization of scientific assemblies, publications, or any other means.” Although it is not formally associated with the United Nations, COSPAR does organize scientific symposia on behalf of and provide information and advice to the UN Committee on the Peaceful Uses of Outer Space. For more about COSPAR see https://cosparhq.cnes.fr.

¹² NASEM, The Goals, Rationales, and Definition of Planetary Protection: Interim Report, The National Academies Press, Washington, D.C., 2017.

In both the interim report and in this final report, the committee defines planetary protection in terms of avoiding harmful biological and organic contamination. Other forms of contamination (e.g., with abiotic chemical, mechanical, or esthetic consequences) can also occur during planetary exploration missions. However, in this report, the committee focuses on effects that can interfere with searches for extraterrestrial life or the well-being of terrestrial life.

DEFINITION AND USE OF THE TERM “POLICY”

NASA’s definition of policy refers to “the philosophies, fundamental values, and general direction of the Agency or Center [that] are used to determine present and future decisions.” NASA adds that “because established policies are general in nature, they may need more specific requirements established in procedural requirements for full implementation.”¹³

This definition works well in the context of planetary protection. The committee believes that NASA’s planetary protection policy can be developed as a set of guiding principles that point to a course of action (a plan) that accomplishes goals that are clearly articulated. The policy is also required to establish clear responsibilities for leadership within the agency for formulating and executing that plan. “Policy” in this context is not the detailed implementation requirements or performance standards that are established for particular planetary exploration missions. Those detailed requirements and technical goals are most effective when they flow down from the policy (principles and guidelines) in a way that can be validated for compliance and effectiveness. More general requirements that describe how high-level policy will be executed and that reflect the application of broad scientific and technical knowledge to meet planetary protection goals do become an element of policy.

NASA has, to date, cited the COSPAR planetary protection policy as its principal guidance, although that policy is not binding on member states (or only insofar as the states adopt it). However, the United Nations (UN) Committee on the Peaceful Uses of Outer Space, of which the United States is a member, has endorsed COSPAR as the appropriate international authority for creating consensus planetary protection guidelines.¹⁴

The COSPAR policy goes beyond the definition of policy in the foregoing paragraph and includes substantial detail on requirements and goals for planetary exploration missions. Member states do have binding obligations under the OST, but the treaty’s language does not address, in and of itself, an implementation policy (i.e., a course of action for specific space missions). Further, NASA has played a particularly influential role in the COSPAR process for determining, reviewing, and updating the COSPAR policy and has then used the COSPAR guidelines as justification, translating its own policy into implementing requirements and processes.

Finding: Creating a more arms-length relationship within NASA between those responsible for the development of planetary protection policies and those responsible for implementing the requirements deriving from the policies would create a greater sense of equity and fairness.

ETHICAL ISSUES

In its deliberations, the committee recognized that ethical issues also permeate planetary protection endeavors. The origins of planetary protection in the 1950s reflect ethical thinking about forward and backward contamination at a time when the policies and international law that characterize this area today did not exist. The development of planetary protection processes, such as in COSPAR in the early 1960s, and legal obligations in the OST in 1967 created a complex mosaic of scientific, political, legal, and ethical issues.

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¹³ NASA, NPR 1400.1G, NASA Directives and Charters Procedural Requirements.

¹⁴ See paragraph 25 of UN Committee on the Peaceful Uses of Outer Space, “Space Science for Global Development: Report on the United Nations Office for Outer Space Affairs and Committee on Space Research Coordination Meeting in Support of the Preparations for UNISPACE+50,” Vienna, Austria, May 22-23, 2017, and paragraph 332 of UN, “Report of the Committee on the Peaceful Uses of Outer Space, Sixtienth [sic] Session (7-17 June 2017),” General Assembly, Official Records, Seventy-second Session, Supplement No. 20, http://www.unoosa.org/res/oosadoc/data/documents/2017/aac_1052017crp/aac_1052017crp_25_0_html/AC105_2017_CRP25E.pdf and http://www.unoosa.org/oosa/en/ourwork/copuos/2017/index.html.

Planetary protection experts recognize that the changing nature of space exploration, including plans to send humans to Mars and the growth in private-sector space activities, presents ethical challenges as well as scientific, political, and legal ones. For example, a 2010 COSPAR Workshop on Ethical Considerations for Planetary Protection in Space Exploration at Princeton University considered whether existing policy adequately captured the range of ethical issues emerging with changes in space exploration goals, technologies, and participants.¹⁵

Among other things, the workshop participants recommended expanding planetary protection policy to address ethical concerns about contamination of planetary bodies “beyond biological and organic constituent contamination.”¹⁶ These concerns include the need to value and protect non-living extraterrestrial environments. The workshop participants acknowledged that expanding the scope of planetary protection ethics would require developing new policy processes, such as a separate COSPAR track “to provide guidance on requirements/best practices for protection of non-living/non-life-related aspects of outer space and celestial bodies.”¹⁷

The Princeton workshop acknowledged that its recommendations required greater attention in COSPAR and beyond on the substantive scope and procedural needs of planetary protection ethics. The implications of actually finding extraterrestrial life would also require an expansion of planetary protection ethics. However, dialogue on expanding planetary protection ethics has not advanced sufficiently to permit the committee to make relevant findings and recommendations. Nor did the committee believe it had the mandate to study specifically the implications of an expanded ethical approach to planetary protection, especially given the many challenges to existing planetary protection policy objectives and processes. A number of these challenges (e.g., the likelihood of future human activities on Mars or the question of setting time horizons beyond which planetary protection requirements might be relaxed or removed) directly affect the core ethical concerns of planetary protection that have been present since the 1950s. Thus, the committee kept these ethical concerns in mind in analyzing planetary protection policy but did not explicitly create a set of findings and recommendations on these issues.

As the number of nations and non-state actors who potentially will be involved in the exploration of outer space in the future increases, there will need to be a generally accepted ethical basis for policy (such as a function played by the Universal Declaration of Human Rights) so that actors not subject to direct governmental authority have a sense of the goals of good policy. While science and technology are easily communicated across cultural and national boundaries, that is not necessarily the case with legal and ethical principles, and unrecognized intercultural differences can lead to serious misunderstandings. The broader the participation in space exploration becomes, the more such intercultural differences need to be understood. Closer to home, the biological research community has long been a leader in flagging ethical issues associated with research progress, the most recent having been CRISPR,¹⁸ and would be attuned to working with similar issues in the space context. Periodic updates of ethical implications could be a way to convey norms to the international public and private space community as concerns arise; formal COSPAR policy would presumably follow. NASA, by convening the updates would have a new tool to extend its leadership in planetary protection policy.

HOW TO READ THIS REPORT

The committee recognizes that this report will likely be read by individuals with varying degrees of interest in and familiarity with the history and practice of planetary protection. Ideally, every reader will begin on page one and work their way through to the final page. For the more selective reader, the committee offers this guide on how best to read and make use of this report.

Readers interested in the following aspects of the study should consult the chapters indicated:

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¹⁵ J. D. Rummel, M. S. Race, G. Horneck, and the Princeton Workshop Participants, Ethical considerations for planetary protection in space exploration: A workshop, Astrobiology 12(11):1017-1023, 2012.

¹⁶ Ibid., p. 1020.

¹⁷ Ibid.

¹⁸ A genome editing technique that uses a CRISPR (clustered regularly interspaced short palindromic repeats) sequence of DNA and its associated protein to add or remove specific gene sequences to a cell.

• Working definition of planetary protection and its goals—Chapter 1 (section “Interim Report”)
• Historical context—Chapter 2 (all sections)
• Current NASA policy development process—Chapter 3 (all sections)
• Policy development process beyond NASA—Chapter 4 (all sections)
• Challenges posed by future robotic missions to Mars—Chapter 3
• Challenges posed by human missions to Mars—Chapter 5
• Challenges posed by private-sector activities—Chapter 6 (all sections)
• Future of the policy development process—Chapter 5 (later sections, beginning with “Planetary Protection and Humans on Mars”) and Chapter 7 (all sections)
• Example of the evolution of planetary protection policies—Appendix B

As the committee addressed each element of its charge, the following two overarching conclusions emerged:

• First, the historical underpinnings of planetary protection policy, including the OST as the foundation for policy development; COSPAR’s role in fostering international cooperation on planetary protection guidelines; science-based decision making; and U.S. leadership in policy-making all remain vital.
• Second, some aspects of the current planetary protection policy development process, which has been built on a chain of incremental refinements to legacy approaches over a period of 50 years, are inadequate to respond to the implications of progressively more complex solar system exploration missions. Today’s planetary protection policies have already been forced to grapple with issues not seen since the Apollo Moon landings in the 1960s and the Viking Mars landers in the 1970s, and they will face much greater challenges as efforts such as the Mars sample return campaign, exploration of the icy moons of Jupiter and Saturn, and human landings on Mars take place. And, as noted elsewhere, complex missions are taking place in an environment of programmatic constraints such as cost caps that did not generally exist in the Apollo era.

In the chapters that follow in this report, the committee identifies lessons learned from planetary protection policy development in the past and issues that need to be resolved to make future policies effective. These issues include the need for a comprehensive NASA planetary protection strategic plan that identifies relevant future missions that demand early planetary protection guidance; establishes planetary protection research and technology development investment priorities; creates a robust process for securing independent, expert, outside advice, and peer review; assesses legacy requirements and identifies opportunities for improvement based on new science; improves the clarity of the translation of policy into mission requirements; and engages the federal government and the international community in timely planetary protection policies for sample return and human missions to Mars.

The careful reader of this report will notice that some material appears in several different places in the report. Such repetition is unfortunate but necessary to provide the readers only interested in particular aspects of the planetary protection policy development process with a comprehensive discussion of specific topics (e.g., the intertwined roles of NASA, COSPAR, and the National Academies Space Studies Board in the development of planetary protection policies).¹⁹

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¹⁹ In 1988, the name of the Space Science Board (established in 1958) was changed to the Space Studies Board.