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COSPAR’s Planetary Protection Policy [G. Kminek (ESA), C. Conley (NASA), V. Hipkin (CSA), H. Yano (JAXA)] Responding to concerns raised in the scientific community that missions to the and other celestial bodies might compromise their future scientific exploration, in 1958 the International Council of Scientific Unions (ICSU) established an ad-hoc Committee on Contamination by Extra- terrestrial Exploration (CETEX) to provide advice on these issues. In the next year, this mandate was transferred to the newly founded Committee on Research (COSPAR), which as an interdisciplinary scientific committee of the ICSU (now the International Council for Science) was considered to be the appropriate place to continue the work of CETEX. Since that time, COSPAR has provided an international forum to discuss such under the terms “planetary quarantine” and later “planetary protection”, and has formulated a COSPAR Planetary Protection Policy with associated implementation requirements as an international standard to protect against interplanetary biological and organic contamination, and after 1967 as a guide to compliance with Article IX of the UN Space Treaty in that area (see for reference: UNOOSA 2017, Report of the Committee on the Peaceful Use of , 60th Session, A/72/20, United Nations, New York). Updating the COSPAR Planetary Protection Policy, either as a response to new discoveries or based on specific requests, is a process that involves representatives from the COSPAR Scientific Commissions B (Space Studies of the -Moon System, , and Small Bodies of the ) and F ( Sciences as Related to Space), national and international scientific organisations and unions and individual scientists (Figure 1). After reaching a consensus among the involved parties, the proposed update is formulated by the COSPAR Panel on Planetary Protection and submitted to the COSPAR Bureau and Council for review and approval.

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The COSPAR Planetary Protection Policy and 26.7 of 1964 [2], the Report of the described in this paper is the currently approved Consultative Group on Potentially Harmful version (dated March 2017) and based on the Effects of Space Experiments of 1966, the COSPAR Panel on Planetary Protection Report of the same Group of 1967, and the Colloquium (published in Report of the COSPAR/IAU Workshop of 2002 Today, #195, April 2016) and the COSPAR [3], Panel on Planetary Protection Business Meeting notes with appreciation and interest the (2 August 2016). Updates affect only some extensive work done by the Panel on Standards requirements for (Mars Special Regions) for Sterilization and its successors and for (new requirements) with the Panel on Planetary Quarantine and the Panel respect to the previous version of the policy on Planetary Protection and published in Space Research Today, #193, August 2015. accepts that for certain space mission/target body combinations, controls on Preamble contamination shall be imposed in accordance Noting that COSPAR has concerned with a specified range of requirements, based on itself with questions of biological the following policy statement: contamination and spaceflight since its very The conduct of scientific investigations inception, and of possible forms, noting that Article IX of the Treaty on precursors, and remnants must not be Principles Governing the Activities of States in jeopardized. In addition, the Earth must the Exploration and Use of Outer Space, be protected from the potential hazard Including the Moon and Other Celestial Bodies posed by extraterrestrial carried (also known as the UN Space Treaty of 1967) by a returning from an states that [1]: interplanetary mission. Therefore, for certain space mission/target “States Parties to the Treaty shall pursue combinations, controls on contamination studies of outer space, including the shall be imposed in accordance with Moon and other celestial bodies, and issuances implementing this policy. ([4, conduct exploration of them so as to 5]; ESA PPWG 2008) avoid their harmful contamination and also adverse changes in the environment The five categories for target body/mission type of the Earth resulting from the combinations and their respective suggested introduction of extraterrestrial matter, ranges of requirements are described as follows, and where necessary, shall adopt and in Table 1. Assignment of categories for appropriate measures for this purpose.” specific mission/body combinations is to be determined by the best multidisciplinary therefore, COSPAR maintains and scientific advice. For new determinations not promulgates this planetary protection policy for covered by this policy, such advice should be the reference of spacefaring nations, both as an obtained through the auspices of the Member international standard on procedures to avoid National Scientific Institutions of COSPAR. In organic-constituent and biological contam- case such advice is not available, COSPAR will ination in , and to provide consider providing such advice through an ad accepted guidelines in this area to guide hoc multidisciplinary committee formed in compliance with the wording of this UN Space consultation with its Member National Treaty and other relevant international Scientific Institutions and International agreements. Scientific Unions: Policy Category I includes any mission to a target COSPAR, body which is not of direct interest for Referring to COSPAR Resolutions 26.5 understanding the process of chemical 13 evolution or the origin of life. No protection of body of chemical evolution and/or origin of life such bodies is warranted and no planetary interest and for which scientific opinion protection requirements are imposed by this provides a significant2 chance of contamination policy. which could compromise future investigations. Requirements imposed include rather detailed Category II missions comprise all types of documentation (more involved than Category missions to those target bodies where there is III), including a bioassay to enumerate the significant interest relative to the process of bioburden, a probability of contamination chemical evolution and the origin of life, but analysis, an inventory of the bulk constituent where there is only a remote1 chance that organics and an increased number of contamination carried by a spacecraft could implementing procedures. The implementing compromise future investigations. The procedures required may include trajectory requirements are for simple documentation biasing, , bioburden reduction, only. Preparation of a short planetary protection possible partial sterilization of the direct contact plan is required for these projects hardware and a bioshield for that hardware. primarily to outline intended or potential impact Generally, the requirements and compliance are targets, brief Pre- and Post-launch analyses similar to Viking, with the exception of detailing impact strategies, and a Post- complete lander/probe sterilization. Category encounter and End-of-Mission Report which IV specifications for selected solar system will provide the location of impact if such an bodies are set forth in the Appendix to this event occurs. Solar system bodies considered to document. Solar system bodies considered to be classified as Category II are listed in the be classified as Category IV also are listed in the Appendix to this document. Appendix. Category III missions comprise certain types Category V missions comprise all Earth-return of missions (mostly flyby and orbiter) to a target missions. The concern for these missions is the body of chemical evolution and/or origin of life protection of the terrestrial system, the Earth interest and for which scientific opinion and the Moon. (The Moon must be protected provides a significant2 chance of contamination from back contamination to retain freedom which could compromise future investigations. from planetary protection requirements on Requirements will consist of documentation Earth-Moon travel.) For solar system bodies (more involved than Category II) and some deemed by scientific opinion to have no implementing procedures, including trajectory indigenous life forms, a subcategory biasing, the use of cleanrooms during spacecraft “unrestricted Earth return” is defined. Missions assembly and testing, and possibly bioburden in this subcategory have planetary protection reduction. Although no impact is intended for requirements on the outbound phase only, Category III missions, an inventory of bulk corresponding to the category of that phase constituent organics is required if the (typically Category I or II). For all other probability of impact is significant. Category III Category V missions, in a subcategory defined specifications for selected solar system bodies as “restricted Earth return,” the highest degree are set forth in the Appendix to this document. of concern is expressed by the absolute Solar system bodies considered to be classified prohibition of destructive impact upon return, as Category III also are listed in the Appendix. the need for containment throughout the return Category IV missions comprise certain types phase of all returned hardware which directly of missions (mostly probe and lander) to a target contacted the target body or unsterilized

1 “Remote” here implies the absence of 2 “Significant” here implies the presence of environments where terrestrial could environments where terrestrial organisms could survive and replicate, or a very low likelihood of survive and replicate, and some likelihood of transfer transfer to environments where terrestrial organisms to those places by a plausible mechanism. could survive and replicate. 14 material from the body, and the need for hardware. containment of any unsterilized sample 4. The organic inventory of all impacting or collected and returned to Earth. Post-mission, landed spacecraft or spacecraft-components, for there is a need to conduct timely analyses of any quantities exceeding 1 kg. unsterilized sample collected and returned to Earth, under strict containment, and using the 5. Intended minimum distance from the most sensitive techniques. If any sign of the of the target body for launched components, for existence of a nonterrestrial replicating entity is those vehicles not intended to land on the body. found, the returned sample must remain 6. Approximate orbital parameters, expected or contained unless treated by an effective realized, for any vehicle which is intended to be sterilizing procedure. Category V concerns are placed in around a solar system body. reflected in requirements that encompass those of Category IV plus a continuing monitoring of 7. For the end-of-mission, the disposition of the project activities, studies and research (i.e., in spacecraft and all of its major components, sterilization procedures and containment either in space or for landed components by techniques). position (or estimated position) on a . Further, COSPAR ([3, 6, 7, 8]) Recommends that COSPAR members inform COSPAR when establishing planetary Appendix: Implementation guidelines and protection requirements for planetary missions, category specifications for individual target and bodies Recommends that COSPAR members Implementation guidelines on the use of provide information to COSPAR within a clean-room technology for outer-planet reasonable time not to exceed six months after missions launch about the procedures and computations COSPAR, used for planetary protection for each flight and again within one year after the end of a solar- Noting that in the exploration of the system exploration mission about the areas of outer planets, the probabilities of growth of the target(s) which may have been subject to contaminating terrestrial micro-organisms are contamination. COSPAR will maintain a extremely low, reflecting the fact that the repository of these reports, make them available environments of these planets appear hostile to to the public, and annually deliver a record of all known biological processes, these reports to the Secretary General of the noting also that these environments do United Nations. For multinational missions, it is not preclude the possibility of indigenous life suggested that the lead partner should take the forms in some of these environments, lead in submitting these reports. recognizing that the search for life is a Reports should include, but not be limited to, potentially valid objective in the exploration of the following information: the outer solar system, 1. The estimated bioburden at launch, the recognizing that the organic chemistry of methods used to obtain the estimate (e.g., assay these bodies remains of paramount importance techniques applied to spacecraft or a proxy), and to our understanding of the process of chemical the statistical uncertainty in the estimate. evolution and its relationship to the origin of 2. The probable composition (identification) of life, the bioburden for Category IV missions, and for recognizing that study of the processes Category V “restricted Earth return” missions. of the pre-biotic organic syntheses under natural 3. Methods used to control the bioburden, conditions must not be jeopardized, decontaminate and/or sterilize the space flight recommends the use of the best available 15 clean-room technology, comparable with that cannot be assured, OR employed for the Viking mission, for all  The sample containment system of a missions to the outer planets and their . mission classified as “Restricted Earth ([9]) return” is thought to be compromised, and sample sterilization is impossible, Numerical implementation guidelines for then the sample to be returned shall be forward contamination calculations abandoned, and if already collected the To the degree that numerical guidelines are spacecraft carrying the sample must not be required to support the overall policy objectives allowed to return to the Earth or the Moon. of this document, and except where numerical requirements are otherwise specified, the Category-specific listing of target body/ guideline to be used is that the probability that a mission types planetary body will be contaminated during the Category I: Flyby, Orbiter, Lander: period of exploration should be no more than Undifferentiated, metamorphosed ; ; 1x10-3. The period of exploration can be others to-be-defined (TBD) assumed to be no less than 50 years after a Category II: Flyby, Orbiter, Lander: ; Category III or IV mission arrives at its Moon (with organic inventory); ; protected target. No specific format for Carbonaceous Chondrite Asteroids; ; probability of contamination calculations is ; ; ; *; ; specified. *; *; /Charon*; ; Kuiper- Guidelines on the implementation of an Belt Objects > 1/2 the size of Pluto*; Kuiper- organic inventory Belt Objects < 1/2 the size of Pluto; others TBD A spacecraft organic inventory includes a Category III: Flyby, Orbiters: Mars; ; listing of all organic materials carried by a Enceladus; others TBD spacecraft which are present in a total mass Category IV: Lander Missions: Mars; Europa; greater than 1 kg. A complete inventory should Enceladus; others TBD include organic products that may be released into the environment of the protected solar Category V: Any Earth-return mission system body by propulsion and life support “Restricted Earth return”: Mars; Europa; others systems (if present), and include a quantitative TBD and qualitative description of major chemical constituents and the integrated quantity of “Unrestricted Earth return”: Venus, Moon; minor chemical constituents present. others TBD Trajectory biasing *The mission-specific assignment of these bodies to Category II must be supported by an The probability of impact on Mars by any part analysis of the “remote” potential for of the shall be ≤ 1x10-4 for a time contamination of the liquid- environments period of 50 years after launch. that may exist beneath their (a Implementation guidelines for Category V probability of introducing a single viable missions terrestrial of < 1 x 10-4), addressing both the existence of such environments and the If during the course of a Category V mission prospects of accessing them. there is a change in the circumstances that led to its classification, or a mission failure, e.g.: Category III/IV/V requirements for Mars  New data or scientific opinion arise that Missions to Mars would lead to the reclassification of a Note: All bioburden constraints are defined mission classified as “Unrestricted with respect to the number of aerobic Earth return” to “Restricted Earth that survive a heat shock of return,” and safe return of the sample 16

80°C for 15 minutes (hereinafter “spores”) and either the entire landed system is are cultured on (Tryptic-Soy-Agar) TSA at restricted to a surface bioburden level 32°C for 72 hours. of ≤ 30* spores, OR the subsystems which directly contact the special Category III. Mars orbiters will not be required region shall be sterilized to these levels, to meet orbital lifetime requirements* if they and a method of preventing their achieve total (surface, mated, and encapsulated) recontamination prior to accessing the bioburden levels of ≤ 5 x 105 spores. (*Defined special region shall be provided. as 20 years after launch at greater than or equal to 99% probability, and 50 years after launch at If an off-nominal condition (such as a hard greater than or equal to 95% probability.) ([10]) landing) would cause a high probability of inadvertent biological contamination of the Category IV for Mars is subdivided into IVa, special region by the spacecraft, the entire IVb, and IVc: landed system must be sterilized to a surface Category IVa. Lander systems not carrying bioburden level of ≤ 30* spores and a total instruments for the investigations of extant (surface, mated, and encapsulated) bioburden life are restricted to a surface bioburden level of ≤ 30 + (2 x 105)* spores. level of ≤ 3 x 105 spores, and an average of ≤ *This figure takes into account the occurrence 300 spores per square meter. of hardy organisms with respect to the Category IVb. For lander systems designed to sterilization modality. This specification investigate extant martian life, all of the assumes attainment of Category IVa surface requirements of Category IVa apply, along with cleanliness, followed by at least a four order-of- the following requirement: magnitude reduction in viable organisms. Verification of bioburden level is based on pre-  The entire landed system is restricted to sterilization bioburden assessment and a surface bioburden level of ≤ 30* knowledge of reduction factor of the spores, or to levels of bioburden sterilization modality. reduction driven by the and sensitivity of the particular life- Planned 3-sigma pre-launch landing ellipses detection experiments, OR must be evaluated on a case-by-case basis as  The subsystems which are involved in part of the (landing) site selection process, to the acquisition, delivery, and analysis determine whether the mission would land or of samples used for life detection must come within contamination range of areas or be sterilized to these levels, and a volumes meeting the parameter definition for method of preventing recontamination Mars Special Regions or would impinge on of the sterilized subsystems and the already described features that must be treated contamination of the material to be as Mars Special Regions. The evaluation must analyzed is in place. be based on the latest scientific evidence and in particular include an assessment of the extent to Category IVc. For missions which investigate which the and water activity values martian special regions (see definition below), specified for Mars Special Regions are even if they do not include life detection separated in time. The evaluation must be experiments, all of the requirements of updated during the mission whenever new Category IVa apply, along with the following evidence indicates that the landing ellipse requirement: and/or the operational environment contain or  Case 1. If the landing site is within the are in contamination range of areas or volumes special region, the entire landed system meeting the parameter definition for Mars is restricted to a surface bioburden level Special Regions or already described features of ≤ 30* spores. that must be treated as Mars Special Regions  Case 2. If the special region is accessed [11]. through horizontal or vertical mobility, 17

Definition of “Special Region” ‡Observational evidence for Recurrent Slope Lineae (RSL), adapted from [13]: A Special Region is defined as a region within which terrestrial organisms are likely to  Confirmed: observed simultaneous replicate. Any region which is interpreted to incremental growth of flows on a warm have a high potential for the existence of extant slope, fading, and recurrence of this martian life forms is also defined as a Special sequence in multiple Mars years Region.  Partially confirmed: observed either Given current understanding of terrestrial incremental growth or recurrence organisms, Special Regions are defined as areas  Candidate: slope lineae that resemble or volumes within which sufficient water RSL but where observations needed for activity AND sufficiently warm to partial confirmation are currently permit replication of Earth organisms may exist. lacking The physical parameters delineating applicable Spacecraft-induced special regions are to be water activity and temperature thresholds are evaluated, consistent with these limits and given below: features, on a case-by-case basis.  Lower limit for water activity: 0.5; In the absence of specific information, no Upper limit: 1.0 Special Regions are currently identified on the  Lower limit for temperature: -28C basis of possible martian life forms. If and when [11]; No Upper limit defined information becomes available on this subject,  Timescale within which limits can be Special Regions will be further defined on that identified: 500 years basis [14]. Spacecraft-induced special regions are to be evaluated, consistent with these limits and Sample Return Missions from Mars features, on a case-by-case basis. Category V. The Earth return mission is Observed features to be treated as Special classified, “Restricted Earth return.” Regions until demonstrated otherwise [11]:  Unless specifically exempted, the  Gullies (taxon 2-4)†, and bright streaks outbound leg of the mission shall meet associated with gullies Category IVb requirements. This  Subsurface cavities provision is intended to avoid “false  Subsurface below 5 meters positive” indications in a life-detection  Confirmed and partially confirmed and hazard-determination protocol, or Recurrent Slope Lineae (RSL)‡ in the search for life in the sample after it is returned. A “false positive” could Features, if found, to be treated as a Special prevent distribution of the sample from Region until demonstrated otherwise [11]: containment and could lead to  Groundwater unnecessary increased rigor in the  Source of requirements for all later Mars  Geothermal activity missions.  Modern outflow channel  Unless the samples to be returned from Mars are subjected to an accepted and Observed features that require a case-by-case approved sterilization process, the evaluation before being classified as a Special canister(s) holding the samples Region [11]: returned from Mars shall be closed,  Dark streaks with an appropriate verification  Pasted-on terrain process, and the samples shall remain contained during all mission phases  Candidate RSL‡ through to a receiving facility †Description for Gully taxon [12] 18

where it (they) can be opened under  For a landed mission conducting containment. surface operations, it will not be  The mission and the spacecraft design possible for all -associated must provide a method to “break the processes and mission operations to be chain of contact” with Mars. No conducted within entirely closed uncontained hardware that contacted systems. Mars, directly or indirectly, shall be  Crewmembers exploring Mars, or their returned to Earth. Isolation of such support systems, will inevitably be hardware from the Mars environment exposed to martian materials. shall be provided during sample In accordance with these principles, specific container loading into the containment implementation guidelines for human missions system, launch from Mars, and any in- to Mars include: flight transfer operations required by the mission.  Human missions will carry microbial  Reviews and approval of the populations that will vary in both kind continuation of the flight mission shall and quantity, and it will not be be required at three stages: 1) prior to practicable to specify all aspects of an launch from Earth; 2) prior to leaving allowable microbial population or Mars for return to Earth; and 3) prior to potential contaminants at launch. Once commitment to Earth re-entry. any baseline conditions for launch are  For unsterilized samples returned to established and met, continued Earth, a program of life detection and monitoring and evaluation of microbes biohazard testing, or a proven carried by human missions will be sterilization process, shall be required to address both forward and undertaken as an absolute precondition backward contamination concerns. for the controlled distribution of any  A quarantine capability for both the portion of the sample. entire crew and for individual crewmembers shall be provided during Principles and Guidelines for Human Missions and after the mission, in case potential to Mars contact with a martian life-form occurs.  The intent of this planetary protection policy is A comprehensive planetary protection the same whether a mission to Mars is protocol for human missions should be conducted robotically or with human explorers. developed that encompasses both Accordingly, planetary protection goals should forward and backward contamination not be relaxed to accommodate a human concerns, and addresses the combined mission to Mars. Rather, they become even human and robotic aspects of the more directly relevant to such missions—even mission, including subsurface explor- if specific implementation requirements must ation, sample handling, and the return differ. General principles include: of the samples and crew to Earth.  Neither robotic systems nor human  Safeguarding the Earth from potential activities should contaminate “Special back contamination is the highest Regions” on Mars, as defined by this planetary protection priority in Mars COSPAR policy. exploration.  Any uncharacterized martian site  The greater capability of human should be evaluated by robotic pre- explorers can contribute to the cursors prior to crew access. astrobiological Information may be obtained by either only if human-associated precursor robotic missions or a robotic contamination is controlled and component on a human mission. understood.  Any pristine samples or sampling 19

components from any uncharacterized  Probability of landing on Europa or sites or Special Regions on Mars should Enceladus be treated according to current  The mechanisms and timescales of planetary protection category V, transport to a Europan or Enceladian restricted Earth return, with the proper subsurface liquid water environment handling and testing protocols.  Organism survival and proliferation  An onboard crewmember should be before, during, and after subsurface given primary responsibility for the transfer implementation of planetary protection provisions affecting the crew during the Preliminary calculations of the probability of mission. contamination suggest that bioburden reduction will likely be necessary even for Europa and  Planetary protection requirements for Enceladus orbiters (Category III) as well as for initial human missions should be based landers, requiring the use of on a conservative approach consistent technology and the cleanliness of all parts with a lack of knowledge of martian before assembly, and the monitoring of environments and possible life, as well spacecraft assembly facilities to understand the as the of human support bioburden and its microbial diversity, including systems in those environments. specific problematic species. Specific methods Planetary protection requirements for should be developed to eradicate problematic later missions should not be relaxed species. Methods of bioburden reduction should without scientific review, justification, reflect the type of environments found on and consensus. Europa or Enceladus, focusing on Earth Category III/IV/V requirements for Europa most likely to survive on Europa and Enceladus [11] or Enceladus, such as cold and tolerant Missions to Europa and Enceladus organisms [15].

Category III and IV. Requirements for Europa Sample Return Missions from Europa and and Enceladus flybys, orbiters and landers, Enceladus including bioburden reduction, shall be applied in order to reduce the probability of inadvertent Category V. The Earth return mission is contamination of an Europan or Enceladan classified, “Restricted Earth return.” ocean to less than 1x10-4 per mission. The  Unless specifically exempted, the probability of inadvertent contamination of a outbound leg of the mission shall meet Europan or Enceladan ocean of 1x10-4 applies the contamination control requirements to all mission phases including the duration that given above. This provision should spacecraft introduced terrestrial organisms avoid “false positive” indications in a remain viable and could reach a sub-surface life-detection and hazard-determination liquid water environment. These requirements protocol, or in the search for life in the will be refined in future years, but the sample after it is returned. A “false calculation of this probability should include a positive” could prevent distribution of conservative estimate of poorly known the sample from containment and could parameters, and address the following factors, lead to unnecessary increased rigor in at a minimum: the requirements for all later Europa or  Bioburden at launch Enceladus missions.   Cruise survival for contaminating Unless the samples to be returned from organisms Europa or Enceladus are subjected to an accepted and approved sterilization  Organism survival in the radiation process, the canister(s) holding the environment adjacent to Europa or samples returned from Europa or Enceladus Enceladus shall be closed, with an 20

appropriate verification process, and Sample Return Missions from Small Solar the samples shall remain contained System Bodies during all mission phases through Category V. Determination as to whether a transport to a receiving facility where it mission is classified “Restricted Earth return” (they) can be opened under or not shall be undertaken with respect to the containment. best multidisciplinary scientific advice, using  The mission and the spacecraft design the framework presented in the 1998 report of must provide a method to “break the the US National Research Council’s Space chain of contact” with Europa or Studies Board entitled, Evaluating the Enceladus. No uncontained hardware Biological Potential in Samples Returned from that contacted material from Europa, Planetary Satellites and Small Solar System Enceladus or their plumes, shall be Bodies: Framework for Decision Making [16]. returned to the Earth’s or the Specifically, such a determination shall address Moon. Isolation of such hardware from the following six questions for each body the Europan or Enceladan environment intended to be sampled: shall be provided during sample container loading into the containment 1. Does the preponderance of scientific system, launch from Europa or evidence indicate that there was never Enceladus, and any in-flight transfer liquid water in or on the target body? operations required by the mission. 2. Does the preponderance of scientific  Reviews and approval of the evidence indicate that metabolically useful continuation of the flight mission shall energy sources were never present? be required at three stages: 1) prior to 3. Does the preponderance of scientific launch from Earth; 2) subsequent to evidence indicate that there was never sample collection and prior to a sufficient organic matter (or CO2 or maneuver to enter a biased Earth return carbonates and an appropriate source of trajectory; and 3) prior to commitment reducing equivalents) in or on the target to Earth re-entry. body to support life?  For unsterilized samples returned to 4. Does the preponderance of scientific Earth, a program of life detection and evidence indicate that subsequent to the biohazard testing, or a proven disappearance of liquid water, the target sterilization process, shall be body has been subjected to extreme undertaken as an absolute precondition temperatures (i.e., >160°C)? for the controlled distribution of any 5. Does the preponderance of scientific portion of the sample [16]. evidence indicate that there is or was sufficient radiation for biological Category requirements for small solar sterilization of terrestrial life forms? system bodies 6. Does the preponderance of scientific Missions to Small Solar System Bodies evidence indicate that there has been a natural influx to Earth, e.g., via , Category I, II, III, or IV. The small bodies of of material equivalent to a sample returned the solar system not elsewhere discussed in this from the target body? policy represent a very large class of objects. Imposing forward contamination controls on For containment procedures to be necessary these missions is not warranted except on a (“Restricted Earth return”), an answer of "no" case-by-case basis, so most such missions or “uncertain” needs to be returned to all six should reflect Categories I or II. Further questions. elaboration of this requirement is anticipated. For missions determined to be Category V, “Restricted Earth return,” the following requirements shall be met:

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 Unless specifically exempted, the No uncontained hardware that outbound leg of the mission shall meet contacted the body, directly or contamination control requirements to indirectly, shall be returned to Earth. avoid “false positive” indications in a Isolation of such hardware from the life-detection and hazard-determination body’s environment shall be provided protocol, or in any search for life in the during sample container loading into sample after it is returned. A “false the containment system, launch from positive” could prevent distribution of the body, and any in-flight transfer the sample from containment and could operations required by the mission. lead to unnecessary increased rigor in  Reviews and approval of the the requirements for all later missions continuation of the flight mission shall to that body. be required at three stages: 1) prior to  Unless the samples to be returned are launch from Earth; 2) prior to leaving subjected to an accepted and approved the body or its environment for return sterilization process, the canister(s) to Earth; and 3) prior to commitment to holding the samples shall be closed, Earth re-entry. with an appropriate verification  For unsterilized samples returned to process, and the samples shall remain Earth, a program of life detection and contained during all mission phases biohazard testing, or a proven through transport to a receiving facility sterilization process, shall be where it (they) can be opened under undertaken as an absolute precondition containment. for the controlled distribution of any  The mission and the spacecraft design portion of the sample [16] must provide a method to “break the chain of contact” with the small body.

Figure 1: Process to update the COSPAR planetary protection policy

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E., Kolmasová, I., Lindberg, R.E., Meyer, M., Acknowledgements Raulin, F., Reitz, G., Rennó, N.O., Rettberg, P., The authors wish to acknowledge the numerous Rummel, J.D., Saunders, M.P., Schwehm, G., scientists who have helped over the previous Sherwood, B., Smith, D.H., Stabekis, P.D., and decades to formulate, review and update the Vago, J. COSPAR Panel on Planetary planetary protection policy. The authors also Protection Colloquium Report, Space Res. would like to thank the main and deputy Today, 195, 2016. scientific organisers of the Panel on Planetary 12. Rummel, J.D, Beaty, D.W., Jones, M.A, Protection sessions during the biennual Bakermans, C., Barlow, N.G., Boston, P.J., COSPAR Scientific Assemblies. Chevrier, V.F., Clark, B.C., de Vera, JP.P., References Gough, R.V., Hallsworth, J.E., Head, J.W., 1. United Nations, Treaty on principles gov- Hipkin, V.J., Kieft, T.L., McEwen, A.S., erning the activities of states in the exploration Mellon, M.T., Mikucki, J.A., Nicholson, W.L., and use of outer space, including the moon and Omelon, C.R., Peterson, R., Roden, E.E., other celestial bodies, Article IX, U.N. Doc. Lollar, B.S., Tanaka, K.L., Viola, D., and Wray, A/RES/2222/(XXI) 25 Jan 1967; TIAS No. J.J., A new Analysis of Mars “Special Regions”: 6347, 1967. Findings of the Second MEPAG Special Regions Science Analysis Group (SR-SAG2), 2. COSPAR. COSPAR RESOLUTION 26.5, 14, 887-968, 2014. COSPAR Information Bulletin 20, 25-26, 1964. 13. McEwen, A.S., Dundas, C.M., Mattson, 3. Rummel, J.D., et al. Report of the S.S., Toigo, A.D., Ojha, L., Wray, J.J., COSPAR/IAU Workshop on Planetary Chojnacki, M., Byrne, S., Murchie, S.L., and Protection, COSPAR, Paris, France, 2002. Thomas, N., Recurrent slope lineae in 4. DeVincenzi, D.L., Stabekis, P.D., Baren- equatorial regions of Mars, Nature goltz, J.B. A proposed new policy for planetary Geosciences, 7, 53-58, 2014. protection, Adv. Space Res. 3, #8, 13-21, 1983. 14. Kminek, G., Conley, C., Allen, C.C., 5. Rummel, J.D., et al. Report of the COSPAR Bartlett, D.H., Beaty, D.W., Benning, L.G., Workshop on Planetary Protection, COSPAR, Bhartia, R., Boston, P.J., Duchaine, C., Farmer, Paris, France, 2008. J.D., Flynn, G.J., Glavin, D.P., Gorby, Y., Hallsworth, J.E., Mogul, R., Moser, D., Buford 6. COSPAR. COSPAR DECISION No. 16, Price, P., Pukall, R., Fernandez-Remolar, D., COSPAR Information Bulletin 50,15-16, 1969. Smith, C.L., Stedman, K., Steele, A., 7. COSPAR. COSPAR INTERNAL DECI- Stepanauskas, R., , H., Vago, J.L., Voytek, SION No. 7/84, Promulgated by COSPAR M.A., Weiss, P.S., Westall, F., Report of the Letter 84/692-5.12.-G. 18 July 1984, 1984. COSPAR Mars Special Regions Colloquium, Adv. Space Res. 46, 811-829, 2010. 8. COSPAR. COSPAR DECISION No. 1/94, COSPAR Information Bulletin 131, 30, 1994. 15. Space Studies Board, National Research Council (US), Preventing the Forward 9. COSPAR. COSPAR DECISION No. 9/76, Contamination of Europa. Task Group on the COSPAR Information Bulletin 76, 14, 1976. Forward Contamination of Europa, National 10. DeVincenzi, D.L., Stabekis, P.D., Academy of Sciences, Washington, D.C., 2000. Barengoltz, J. Refinement of planetary 16. Space Studies Board, National Research protection policy for Mars missions, Adv. Space Council (US), Evaluating the Biological Res. 18, #1/2, 311-316, 1996. Potential in Samples Returned from Planetary 11. Kminek, G., Hipkin, V.J., Anesio, A.M., Satellites and Small Solar System Bodies, Task Barengoltz, J., Boston, P.J., Clark, B.C., Group on Sample Return From Small Solar Conley, C.A., Coustenis, A., Detsis, E., Doran, System Bodies, National Academy of Sciences, P., Grasset, O., Hand, K., Hajime, Y., Hauber, Washington, D.C., 1998. 23

Table 1: Categories for solar system bodies and types of missions [3, 4, 7, 8, 10]

Category I Category II Category III Category IV Category V

Type of Mission Any but Any but Earth No direct Direct contact Earth Return Earth Return contact (flyby, (lander, probe, Return some orbiters) some orbiters) Target Body See See Category- See Category- See Category- See Category- Category- specific listing specific listing specific listing specific listing specific listing Degree of Concern None Record of Limit on Limit on If restricted planned impact impact probability of Earth return: probability and probability non-nominal  No impact contamination impact Passive on Earth or control bioburden Limit on Moon; measures control bioburden  Returned (active control) hardware sterile;  Containme nt of any sample. Representative Range of None Documentation Documentation Documentation Outbound only (all brief): (Category II (Category II Requirements Same category plus): plus):  PP plan as target body/  Pre-launch  Contamin-  Pc analysis outbound report ation plan mission  Post-launch control  Microbial Inbound report  Organics reduction  Post- inventory plan If restricted encounter (as  Microbial Earth return: report necessary) assay plan Documentation  End-of-  Organics (Category II mission Implementing inventory plus): report procedures Implementing  Pc analysis such as: procedures plan  Trajectory such as:  Microbial biasing  Trajectory reduction  Cleanroom biasing plan  Bioburden  Cleanroom  Microbial reduction  Bioburden assay plan (as reduction Implementing necessary)  Partial procedures such sterili- as: zation of contacting  Trajectory 24

hardware biasing (as  Sterile or necessary) contained  Bioshield returned  Monitoring hardware of  Continual bioburden monitoring via of project bioassay activities  Project advanced studies and research If unrestricted Earth return:  None

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