1. A Summary of MEPAG’s Recent Thinking Re: MSR Science
David Beaty
April 4, 2010
Presentation to the Planetary Protection Subcommittee
Pre-decisional: For discussion purposes only

2. Pre-decisional draft for discussion purposes only: Subject to Revision
Introduction
What is MEPAG?: Mars science community forum
How does MEPAG operate?: Science Analysis Groups (SAGs) carry out analyses requested by MEP (and also ESA). Participatory townhalls allow wide participation in program planning.
MEPAG has thought a lot about returned samples: where to acquire them, their nature, and their handling, encapsulation, and quarantine/curation
2008 ND-SAG (Next Decade)
2009 MRR-SAG (Mid-Range Rover)
2010 2R-iSAG (2 Rover)
2011 E2E-iSAG (End-to-end MSR campaign)
6/4/2018
Pre-decisional draft for discussion purposes only: Subject to Revision 8

3. MEPAG’s Recent Thinking re: MSR
2008: ND-SAG
6/4/2018
Pre-decisional draft for discussion purposes only: Subject to Revision 8

4. Summary of the ND-SAG analysis
Define possible scientific objectives for MSR.
Based on analysis of the MEPAG Goals Document.
What kinds of samples are needed to achieve these objectives?
What are the attributes of the sample collection that will maximize its scientific value?
Number of samples
Mass/sample
Many other factors
6/4/2018
Pre-decisional draft for discussion purposes only: Subject to Revision 8

5. Scientific Objectives for MSR
11 candidate objectives identified.
KEY OBSERVATION:
No single site on Mars will support all of these
Every site on Mars will support some
=> dependency between objectives and landing site
6/4/2018
Pre-decisional draft for discussion purposes only: Subject to Revision

6. Summary of the ND-SAG analysis
Define possible scientific objectives for MSR.
Based on analysis of the MEPAG Goals Document.
What kinds of samples are needed to achieve these objectives?
What are the attributes of the sample collection that will maximize its scientific value?
Number of samples
Mass/sample
Many other factors
6/4/2018
Pre-decisional draft for discussion purposes only: Subject to Revision 8

7. MSR: What Kinds of Samples?
By far the most important, given the proposed objectives. Multiple diverse samples essential.
Irvine
ROCK
Spirit, ; sol 721
At least one relatively large sample, preferably also additional smaller samples.
REGOLITH/ DUST
ATMOSPHERIC GAS
One good sample.
6/4/2018
Pre-decisional draft for discussion purposes only: Subject to Revision

8. The Concept of Sample Suites
ND-SAG FINDING. MSR will have its greatest value if the samples are organized into suites of samples that represent the diversity of the products of various planetary processes.
Similarities and differences between samples in a suite can be as important as the absolute characterization of a single sample
The minimum number for a suite of samples is thought to be 5-8 samples.
Examples: Sampling several rock layers in a stratigraphic sequence, sampling along a hydrothermal alteration gradient, sampling both “ordinary” regolith and local variations (e.g., salts?) in an area.
ND-SAG FINDING. The collection of suites of rocks requires mobility, the capability to assess the range of variation, and the ability to select samples that span the variation.
6/4/2018
Pre-decisional draft for discussion purposes only: Subject to Revision 8

9. Rock Sample Suites: Sedimentary
The geochemical variation with stratigraphic position has been interpreted as a diagenetic redistribution of salts and is central to the water question. This could not have been done with 1-2 samples.
Burns Cliff
Endurance Crater, July 19, 2004 (Opportunity Sol 173)
top bottom
Clark et al., 2005 (EPSL)
6/4/2018
Pre-decisional draft for discussion purposes only: Subject to Revision 8

10. Summary of the ND-SAG analysis
Define possible scientific objectives for MSR.
Based on analysis of the MEPAG Goals Document.
What kinds of samples are needed to achieve these objectives?
What are the attributes of the sample collection that will maximize its scientific value?
Number of samples
Mass/sample
Many other factors
6/4/2018
Pre-decisional draft for discussion purposes only: Subject to Revision 8

11. Sample Size: Rock Samples
Example: meteorite QUE (mass = g)
QUE-94201
Image courtesy Kevin Righter
QUE has been subdivided into over 60 individual samples of some kind or another. EXAMPLE: Utilization of a 1 g chip of this meteorite to make 5 thin sections allowed a great diversity of scientific problems to be addressed by 14 investigators.
6/4/2018
Pre-decisional draft for discussion purposes only: Subject to Revision 8

12. Draft Sample Size: Rock Samples
*Life Detection/Biohazard testing
6/4/2018
Pre-decisional draft for discussion purposes only: Subject to Revision 8

13. Sample Packaging & Labeling
There are several fundamental issues:
ND-SAG & MRR-SAG: For the purpose of the major astrobiology/geology-related questions, samples with water and/or volatile organics must have airtight encapsulation (possibly 2/3 of samples by number).
Organics samples require airtight encapsulation to maintain bulk composition (draft: adequate to contain methane)
Samples containing hydrated minerals (especially sedimentary and hydrothermal suite) require airtight encapsulation to retain their components and to protect other samples from alteration by volatile release.
If there are multiple regolith or dust samples (which is desired), they must be packaged to avoid commingling.
Samples must be uniquely identifiable after they are returned to Earth so that the field relationships can be included in the interpretation.
6/4/2018
Pre-decisional draft for discussion purposes only: Subject to Revision 8

14. Sample Packaging & Labeling Rock sample pulverized
UNACCEPTABLE
Samples mixed
Rock sample pulverized
ACCEPTABLE
UNACCEPTABLE
Rock fractured
Impact test, June 8, 2000 (max. dynamic load ~ 3400 g, avg. ~2290 g). 10 samples of basalt and chalk in separate sample cache tubes with tight-fitting Teflon caps. Many of the teflon caps came off as a result of the impact.
6/4/2018
Pre-decisional draft for discussion purposes only: Subject to Revision 8

15. Draft Composition of the Collection
NOTE: Consensus not yet reached
6/4/2018
Pre-decisional draft for discussion purposes only: Subject to Revision 8

16. MEPAG’s Recent Thinking re: MSR
2008: ND-SAG
2009: MRR-SAG
6/4/2018
Pre-decisional draft for discussion purposes only: Subject to Revision 8

17. Findings Related to Potential Sample Return
MEASUREMENTS NEEDED FOR SAMPLE SELECTION: REVISIT VS. NEW SITE
FINDING: The capabilities needed to do scientific sample selection, acquisition, and documentation for potential return to Earth would be the same whether the rover would be sent to an area that has been previously visited, or to a new unexplored site.
From MRR-SAG: Reducing payload would limit the ability to select or document samples during collection and greatly increase science risk.

18. Findings Related to Potential Sample Return
LANDING SITES
FINDING: There are many candidate sites of high potential interest for a future sample return beyond those previously visited or to be visited by MSL.
In addition, using MSR prioritization criteria, additional sites of high potential priority have been recognized
NRC: Astrobiology Strategy for Mars: Several additional kinds of sites of high interest to astrobiology for a potential future return of samples were noted by the NRC (2007).
Community-generated. At recent Mars-related conferences (LPSC, EPSC, AGU, EGU, AbSciCon, GSA, etc.), the global Mars science community has presented many additional sites and site-related astrobiology hypotheses.

19. Findings Related to Potential Sample Return
LANDING SITES
FINDING: The best way to evaluate the multiple candidate sites from which to consider returning samples is via an open landing site selection competition with sample return selection criteria. A mission such as the proposed MAX-C presents the first opportunity to evaluate new high-potential sites via such a competition.

20. Findings Related to Potential Sample Return RELATIONSHIP BETWEEN IN SITU SCIENCE AND SAMPLE RETURN
The kinds of rocks that would need to be interrogated to achieve the proposed in situ objectives are a class of samples that would also be of crucial interest for potential sample return. Therefore:
MAJOR FINDING: The instruments needed to achieve the proposed in situ objectives are the same instruments needed to select samples for potential return to Earth, and to document their context. Because of these compelling commonalities, it makes sense to merge these two purposes into one mission.

21. MEPAG’s recent thinking re: MSR
2008: ND-SAG
2009: MRR-SAG
2010: 2R-iSAG
6/4/2018
Pre-decisional draft for discussion purposes only: Subject to Revision 8

22. 2RiSAG-Proposed PRIMARY SCIENTIFIC OBJECTIVES, 2018 DUAL-ROVER MISSION
Overall Scientific Objectives
At a site interpreted to contain evidence of past environments with high (past) habitability potential, and with high preservation potential for (past) physical and chemical biosignatures,
Evaluate paleoenvironmental conditions;
Assess the potential for preservation of biotic and/or prebiotic signatures;
Search for possible evidence of past life and prebiotic chemistry
Collect, document, and package in a suitable manner a set of samples sufficient to achieve the proposed scientific objectives of a potential future sample return mission.
Independent Scientific Objectives
ExoMars Rover
Characterize the stratigraphy of ancient rocks and the aqueous/geochemical environment as a function of depth in the shallow subsurface (up to 2 m depth).
Search for possible signs of present life
MAX-C Rover
Characterize exposed sequences of geological units across a lateral extent of several km, documenting geological and geochemical variation at scales from 10^3 down to 10^-5 m.

23. MEPAG’s recent thinking re: MSR
2008: ND-SAG
2009: MRR-SAG
2010: 2R-iSAG
2011: E2E-iSAG
6/4/2018
Pre-decisional draft for discussion purposes only: Subject to Revision 8

24. Team formation happening now
E2E-iSAG Charter
Consolidate and prioritize a reference set of MSR Campaign Science Objectives.
Use to derive the science-related requirements for the individual flight missions, so that trades between them could be worked.
Derived criteria:
Samples (rock, subsurface, regolith, gas)
Instrumentation
Landing site criteria (threshold and qualifying). Do any acceptable sites exist?
Reference Landing sites
Inputs to Technology Planning
Team formation happening now
6/4/2018
Pre-decisional draft for discussion purposes only: Subject to Revision 8

25. Pre-decisional draft for discussion purposes only: Subject to Revision
Summary
Top 6 things that would affect the ultimate scientific value of MSR:
6/4/2018
Pre-decisional draft for discussion purposes only: Subject to Revision 8