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Planetary Protection

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Planetary Protection Considerations for

Mars Sample Return

C. Conley, NASA PPO G. Kminek, ESA PPO

4 August, 2010

Science class should not end in tragedy....Science class should not end in tragedy....Science class should not end in tragedy....Science class should not end in tragedy....Science class should not

The Basic Rationale for Planetary Protection Precautions

(as written by Bart Simpson, Dec. 17, 2000, “Skinner’s Sense of Snow”)


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Planetary Protection Mission Constraints

Depend on the nature of the mission and on the target planet Assignment of categories for each specific mission/body is to

be determined by the “best multidisciplinary scientific advice”» COSPAR will provide it in case such advice is not available to a

nation Examples of specific measures include:

» Reduction of spacecraft biological contamination

» Constraints on spacecraft operating procedures

» Spacecraft organic inventory and restrictions

» Restrictions on the handling of returned samples

» Documentation of spacecraft trajectories and spacecraft material archiving


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PLANET MISSION MISSIONPRIORITIES TYPE

CATEGORY

A Not of direct interest for understanding the Any Iprocess of chemical evolution. No protection of such planets is warranted (no requirements).

B Of significant interest relative to the process of Any IIchemical evolution, but only a remote chance that contamination by spacecraft could jeopardizefuture exploration.

C Of significant interest relative to the process of Flyby, Orbiter IIIchemical evolution and/or the origin of life or forwhich scientific opinion provides a significantchance of contamination which could jeopardize Lander, Probe IVa future biological experiment.

All Any Solar System Body Earth-Return V“unrestricted-” or “restricted Earth-

return”

Planetary Protection Mission Categories


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Planetary Protection Compliance for Mars Sample Return

Three aspects require PP involvement over mission lifetime» Outbound – protect Mars from Earth organisms » Sample Return – protect Earth from Martian organisms » Life Detection and Biohazard Assessment Protocol: Sample

Distribution and Future Missions– Distinguish Earth-originating (round-trip) biota/biomarkers from those of

potentially Martian origin– Demonstrate that samples are safe enough to be released from quarantine for

distribution to investigators

Requirements on the system to allow for sample distribution may be satisfied via several implementation methods at a range of costs, with significant implications for additional scientific investigations


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Category III/IV Requirements for Mars


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Category III/IV Requirements for Mars (cont.)


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Category III/IV Requirements for Mars (cont.)


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Sample Return Missions from Mars

Category V. The Earth return mission is classified, “Restricted Earth return.”

• Unless specifically exempted, the outbound leg of the mission shall meet Category IVb requirements. This provision is intended to avoid “false positive” indications in a life-detection and hazard-determination protocol, or in the search for life in the sample after it is returned. A “false positive” could prevent distribution of the sample from containment and could lead to unnecessary increased rigor in the requirements for all later Mars missions.

• The sample container must be sealed after sample acquisition. A redundant, fail-safe containment with a method for verification of its operation before Earth-return shall be required. The integrity of the flight containment system shall be maintained until the sample is transferred to containment in an appropriate receiving facility.


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Sample Return Missions from Mars (cont.)

Category V, cont.

• The mission and the spacecraft design must provide a method to “break the chain of contact” with Mars. No uncontained hardware that contacted Mars, directly or indirectly, shall be returned to Earth. Isolation of such hardware from the Mars environment shall be provided during sample container loading into the containment system, launch from Mars, and any in-flight transfer operations required by the mission.

• Reviews and approval of the continuation of the flight mission shall be required at three stages: 1) prior to launch from Earth; 2) prior to leaving Mars for return to Earth; and 3) prior to commitment to Earth re-entry.

• A program of life detection and biohazard testing, or a proven sterilization process, shall be undertaken as an absolute precondition for the controlled distribution of any portion of the sample.


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• Samples returned from Mars should be contained and treated as though potentially hazardous until proven otherwise

• If sample containment cannot be verified en route to Earth, the sample and spacecraft should either be sterilized in space or not returned to Earth

• Integrity of sample containment should be maintained through reentry and transfer to a receiving facility

• Controlled distribution of unsterilized materials should only occur if analyses determine the sample not to contain a biological hazard

• Planetary protection measures adopted for the first sample return should not be relaxed for subsequent missions without thorough scientific review and concurrence by an appropriate independent body

SSB Recommendationson Mars Sample Return

Avoiding Backward Contamination: Handling Mars SamplesEarth Ground Facilities:• Mobile Retrieval Units (MRU)

• Sample Receiving Facility (SRF)

• Sample Curation Facility (SCF)

Quarantine(SRF)

Curation(SCF)

Retrieval(MRU)

· Rapid retrieval and containment

Samples declared safe?

· Subsampling· Documentation· Sample distribution· Long-term curation· Cold curation

· Preliminary examination/ characterization

· Subsampling, documentation

· Preliminary search for extinct/ extant life

· Hazard testing

ResearchLaboratories

EEVs

Samples Certified

Safe?

?

Analyzing Returned Samples: The Draft Test Protocol (2002, update

planned)

Perform appropriate testing for biohazard evaluation and life detection

Comply with national regulations and legal constraints:

US National Environmental Protection Act

US Presidential Directive/National Security Council Memorandum #25

Ensure public communication and involvement to the extent necessary for public acceptance* of Mars Sample Return

The perceived benefits of Mars sample return must outweigh the costs

*and funding!


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What Does ‘Potentially Hazardous’ Imply?

• Hazards must be either destroyed or containedContain Mars samples, or sterilize them, to ensure safety of Earth

• Must have sufficient confidence on containmentProvisional requirement: 1x10-6 probability of releasing a single 0.2

micron particle of Mars material into the Earth environment (ESF input)

• Must have approved protocols for containment and testingReview and update Draft Test Protocol using best available advice (next)Requirements on flight system contamination flow back from test

protocols

• Technical requirements flow from the hazard assessment– Impact on design and operation– Impact on flight and ground system (C&C)– Impact on hardware and software– Impact on qualification and acceptance margins

• Technology development needs are dictated by hazard considerations

PP_Subcom_August_2010

Probabilistic Constraints

Premise: Hazard

Requires: Containment & Sterilization

Defined by: Release Probability & Sterility Assurance Level (SAL)

Policy decision (ESF study): Acceptable risk level

Derived technical requirements:Redundancy & Factors of Safety (FoS)

Implementation: Flight/ground system, qualification approach, verification and procedures

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PP_Subcom_August_2010 16

One Take on Risk Assessment...

12th PPWG meeting, recommendation for loss of containment:–Severity level is Catastrophic: potential for severe detrimental environmental effects (conservative assumption for resource allocation, not expected or proven severity level)–Always keep containment/handling visible in the risk log

ECSS-Q-ST-40C

“…samples returned from Mars by spacecraft should be contained and treated as though potentially hazardous until proven otherwise…” because “…the potential for large-scale negative effects on Earth’s inhabitants or environments by a returned martian life form appears to be low, but is not demonstrably zero.”


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Science class should not end in tragedy.... Science class should not end in tragedy