# Presentation: 030713

##  Draft Science Priorities for Mars Sample ReturnPreliminary Results from the MEPAG Next Decade - Science Analysis Group(ND-SAG) February 20, 2008

_*NOTE:*_*  All content in this presentation is a pre-decisional draft for discussion and review only.  Subject to revision.*

## Lars Borg (co-chair), David Des Marais (co-chair), David Beaty, Oded Aharonson, Steve Benner, Don Bogard, John Bridges, Charles Budney, Wendy Calvin, Ben Clark, Jennifer Eigenbrode, Monica Grady, Jim Head, Sidney Hemming, Noel Hinners, Vicky Hipkin, Glenn MacPherson, Lucia Marinangeli, Scott McLennan, Hap McSween, Jeff Moersch, Ken Nealson, Lisa Pratt, Kevin Righter, Steve Ruff, Chip Shearer, Andrew Steele, Dawn Sumner, Steve Symes, Jorge Vago, Frances WestallPLUS 46 additional consultants

- MEPAG ND-SAG Members

## Summary of the 

**logic of this 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
- Several additional factors

- Pre-decisional draft for discussion purposes only:  Subject to Revision

## Summary of the 

**Summary of the **
**logic of this 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

- Pre-decisional draft for discussion purposes only:  Subject to Revision

## Candidate Scientific Objectives for MSR Missions (1 of 2)

* ****NOTE:  No single site on Mars will support all of these.***

- Pre-decisional draft for discussion purposes only:  Subject to Revision

## Candidate Scientific Objectives for MSR Missions (2 of 2)

* ****NOTE:  No single site on Mars will support all of these.***

- Pre-decisional draft for discussion purposes only:  Subject to Revision

## Summary of the 

**Summary of the **
**logic of this 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

- Pre-decisional draft for discussion purposes only:  Subject to Revision

## The Concept of Sample Suites

_**DRAFT 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.

_**DRAFT 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.

*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.*

- Pre-decisional draft for discussion purposes only:  Subject to Revision

## Rock Sample Suites:  Sedimentary

*Endurance Crater, July 19, 2004 (Opportunity Sol 173)*

*Clark et al., 2005 (EPSL)*

**top****	****	****	****   bottom**

- 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**

- Pre-decisional draft for discussion purposes only:  Subject to Revision

## Rock Sample Suites:  Sedimentary

*Endurance Crater, July 19, 2004 (Opportunity Sol 173)*

**Biolaminated sediments, Josefsdal Chert, Barberton (3.33 Ga).  Each of the black layers represents a packet (or packets) of biofilms formed on the surface of littoral sediments (see details below).  The sediments are hydrothermally silicified volcanic sands and silts.**

**Detail of the biolaminated sediments showing carbon enrichment in the dark layers (thin section**

**Further detail showing a wavy biofilm **
**formed on top of the undulating surface of the underlying sediments**

**Barberton, South Africa**

*Images courtesy Frances Westall*

- Pre-decisional draft for discussion purposes only:  Subject to Revision

## Rock Sample Suites:  Igneous

**Irvine**

**Rock Sample Suites:  Igneous**

**Humphrey**

**Backstay**

**Wishstone**

- Analysis of this suite of rocks shows that they are alkaline volcanics, which formed under different conditions or from a very different starting composition than the bulk of Martian rocks.  This sheds light on the complexity of the Martian interior.

*APXS Analyses (Gellert et al., 2006)*

*Images courtesy Hap McSween*

- Pre-decisional draft for discussion purposes only:  Subject to Revision

## Rock Sample Suites:  Hydrothermal

- Active hot spring

- siliceous sinter, Yellowstone. (Photo from Daniele Marchesini)

- False-color Pancam image of an opaline silica outcrop next to Home Plate that was broken open with Spirit's wheel.

**Yellowstone, WY**

**Innocent Bystander**

- Active geyser

**Geysir, Iceland**

***ACTIVE***

***FOSSIL***

*Image courtesy Steve Ruff*

- Pre-decisional draft for discussion purposes only:  Subject to Revision

## Rock Sample Suites:  Hydrothermal

- Lafayette nakhlite carbonate-clay veins

- Px augite
- Sm smectite/nontronite clay
- Sd siderite carbonate

**Lafayette**

**Solfatara, Italy**

*Image courtesy John Bridges*

***ACTIVE***

***FOSSIL***

- Pre-decisional draft for discussion purposes only:  Subject to Revision

## Rock Sample Suites:  Low T & W/R

- True-color Pancam image of the "Clovis" outcrop on the West Spur of Husband Hill, which is an altered volcaniclastic rock showing elevated S, Cl, and Br, highly oxidized Fe, minor goethite, but no detectable clay
- minerals or opaline silica.

- True-color Pancam image of "Watchtower", an altered volcaniclastic rock on Husband Hill.  It is highly oxidized with high P and Ti, hematite and goethite, but no detectable clays or silica.

- These rocks have been interpreted as altered, but under low water/rock conditions and probably low T as well.  The nature of this alteration is still being debated (weathering, acid-fog, impact-related?).

- Low temperature alteration (sulphate formation) of an ancient hot spring deposit (Sulphur Springs, Pilbara, Australia; age Archaean). Photos by Barbara Cavalazzi (Univ. Bologna).

**Watchtower**

**Clovis**

**Pilbara, Australia**

- Pre-decisional draft for discussion purposes only:  Subject to Revision

## Rock Sample Suites:  Low T & W/R

**Rock Sample Suites:  Low T & W/R**

**RAT Hole**

**Brush Spot**

**4.5 cm**

**“****As Is”**

- The blue arrow points to leftover portions of the dark rind that coats Mazatzal and the scrape marks left by the rock abrasion tool. The yellow arrow highlights the bright edges surrounding the leftover rind. The crack in the rock may have once contained fluids out of which minerals precipitated along its walls (red arrows). Mazatzal is a highly coated rock, containing at least four "cake layers": a top coat of dust, a pinking coating, a dark rind and its true interior.

**Mazatzal**

*Images courtesy Scott McLennan*

- Pre-decisional draft for discussion purposes only:  Subject to Revision

## Regolith Samples

**Regolith Samples**

- Most patches of disturbed, bright soil in Gusev are rich in sulfur, but this one has very little sulfur and is about 90 percent silica.

*Soil target "Gertrude Weise“, Spirit, March 29, 2007; sol 1187 *

*Spirit, 01-12-06; sol 721*

- Soil with a salty chemistry dominated by iron-bearing sulfates. These salts may record the past presence of water.

- Basaltic sand

*Soil target “El Dorado“, Spirit*

**“****Ordinary” regolith**

*Sol114A_P2561_1_True_RAD.jpg *

*Images courtesy Steve Ruff and Oded Aharonson*

- Pre-decisional draft for discussion purposes only:  Subject to Revision

## Summary of the 

**Summary of the **
**logic of this 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

- Pre-decisional draft for discussion purposes only:  Subject to Revision

## Sample Size:  Rock Samples

- 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.

**QUE-94201**

**Example:  meteorite QUE-94201 ****(mass = 12.02 g)**

*Image courtesy Kevin Righter*

- Pre-decisional draft for discussion purposes only:  Subject to Revision

## Case History:  QUE-94201

| Type | Mass (g) | Techniques / notes | Information gained |
| --- | --- | --- | --- |
| a) Destructive analysis | 4.416 | SEM, TEM, AMS, INAA, TIMS, stable isotope MS, noble gas MS, XANES, EMPA | Samples allocated to 23 PIs for studies of: Bulk composition (INAA)
Crystallization age (Lu-Hf, Rb-Sr, Sm-Nd, K-Ar, U-Pb) 
Differentiation age (Hf-W, Sm-Nd)
Exposure ages (3He, 21Ne, 38Ar, 81Kr, 10Be, 26Al, 36Cl, 14C, 53Mn)
Rock-atmosphere interactions (C, S, O, H isotopes) |
| b) Thin section production | 2.2 | SEM, TEM, SIMS, XANES, EMPA, optical microscopy | 13 thin sections produced and studied by 29 different PI's from many scientific disciplines; first section allowed classification |
| c) Non-destructive analysis | 0.372 | SEM, magnetic | Textural analysis, rock magnetization |
| d) Still available for study | 5.160 | Includes mass from c) | Sample material still being allocated 12 years later using new techniques and by next generation of planetary scientists |
| e) attrition | 0.346 | Material lost during processing |  |

***CONCLUSION:  We need about 8 g to support a full program of science investigations.***

- Pre-decisional draft for discussion purposes only:  Subject to Revision

## Sample Size:  Rock Samples

- Pre-decisional draft for discussion purposes only:  Subject to Revision

## Sample Size:  Regolith Samples

- Pre-decisional draft for discussion purposes only:  Subject to Revision

## Possible need 

**for some larger samples**

**concretion**

**cemented zone**

**crystal**
**mold**

**laminations**

**London**

**2 cm**

**2 cm**

- One of the RAT holes from the Endurance crater section showing some of the critical textures that would be needed to interpret the sedimentary and diagenetic history.

- Textural and mineralogic differences above and below the black band were essential to interpretation.

*For some textural studies, larger samples are advantageous*

- 5 g

- 20 g

*Wittenoom Dolomite, Hamersley Province,  Western Australia *

**Pilbara, Australia**

*Image courtesy Jen Eigenbrode*

*Image courtesy Scott McLennan*

- Pre-decisional draft for discussion purposes only:  Subject to Revision

## Regolith Sample size 

- MER has defined least three major types of granular components in regolith:  surficial dust, basaltic sand, and components reflecting local (major?) variations in chemistry.
- The regolith appears to be _very different from place to place_ so multiple samples are needed to assess variation.
- Currently requested 1 gm to 25 gm samples
- There is some interest in one sample from the maximum practical depth below the surface (to try to get below an oxidized or UV activated zone).

_**DRAFT FINDING.**_  It is a high priority to plan for 3 separate regolith samples.

- Pre-decisional draft for discussion purposes only:  Subject to Revision

## Dust Sample 

- Three means of acquisition
- Settle on horizontal surface
- Draw air through a filter
- Surficial geological deposit

*Sol589A_P2559_1_False_L257.jpg *

- For Opportunity, the estimated net dust thickness after one year was 1 to 10 microns (reflects both additions and removal).

- False-color Pancam image that shows thin dust drifts at the top of Husband Hill.

*Image courtesy Steve Ruff*

- Pre-decisional draft for discussion purposes only:  Subject to Revision

## Dust Sample size 

- The driving requirement is Investigation IVA-3 (Biohazards), and this _may be mandatory before human exploration_._** **_
- The Draft Test Protocol (Rummel et al., 2002) states that 15 – 25 g is sufficient to carry out the biohazard testing envisioned at that time.
- Also of major interest: Invest. IVA-5 (toxic effects of dust)
- Prefer several 5 g samples of dust/regolith.
- Plan intra-tracheal, corneal, and ingestion studies to determine toxic effects
- Interest related to atmospheric science is both lower priority and needs far less sample material.

_**DRAFT FINDING.**_  A single dust sample of ~5 g from a surficial deposit would be sufficient to meet our needs.

- Pre-decisional draft for discussion purposes only:  Subject to Revision

## Possible Number of Samples 

**(with cache)**

***NOTE:  Consensus not yet reached***

- Pre-decisional draft for discussion purposes only:  Subject to Revision

## Possible Number of Samples 

**(w/o cache)**

***NOTE:  Consensus not yet reached***

- Pre-decisional draft for discussion purposes only:  Subject to Revision

## Sample Acquisition System Priorities

**Sample Acquisition System Priorities**

- Pre-decisional draft for discussion purposes only:  Subject to Revision

## Importance of sampling 

- Discovery of shallow reduced C  by MSL

- Discovery of reduced C with 2 m system by ExoMars

**YES**

**NO**

**YES**

**NO**

***ESSENTIAL***

***NOT NECESSARY***

***NOT NECESSARY***

***PROBABLY NOT NECESSARY***

**Importance of sampling **
**to a depth of 2 - 3 m by MSR**

- Pre-decisional draft for discussion purposes only:  Subject to Revision

## Sample Packaging & Labeling

- There are several fundamental issues:
- 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:  to level of containing 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 that come from _known field context_ must be _uniquely identifiable_ so that the field relationships can be included in the interpretation.

- Pre-decisional draft for discussion purposes only:  Subject to Revision

## UNACCEPTABLE

- 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.

***UNACCEPTABLE***

***UNACCEPTABLE***

***ACCEPTABLE***

***Rock sample pulverized***

***Samples mixed***

***Rock fractured***

- Pre-decisional draft for discussion purposes only:  Subject to Revision

## Sample Packaging

- _FINDINGS_.
- The scientific usefulness of the returned samples depends critically on keeping them from commingling, on being able to uniquely identify them for linkage back to documented field context, and in keeping rock samples mechanically intact.
- Trading sample mass for packaging material is painful, but necessary.  A smaller number or mass of carefully managed samples will be far more valuable than larger number or mass of poorly-managed samples.
- The encapsulation for at least some of the samples must be air-tight to retain volatile components.

- Pre-decisional draft for discussion purposes only:  Subject to Revision

## Temperature Analysis

- Some sample types, because of their mineralogy or potential chemistry, are more vulnerable to degradation than others.  The estimated effect of this degradation on our ability to achieve the candidate objectives is shown on the next slide.

- _FINDING:_  MSR’s scientific objectives can most confidently be met if the samples are kept below -20C, and with less confidence if they are kept below +20C.  Significant damage, particularly to attaining MEPAG life goals, will occur if the samples are allowed to reach +50C for 3 hours.  Temperature monitoring during the return mission will allow assessment of any changes to the samples.

- Pre-decisional draft for discussion purposes only:  Subject to Revision

## Sample Temperature 

- Pre-decisional draft for discussion purposes only:  Subject to Revision

##  Sample Selection & Documentation of Context

- What is the minimum number of measurement types necessary to make effective sample selection decisions and to document the context of the samples collected?
**Case A:**  New site      **Case B:** Revisit previously characterized site

- Pre-decisional draft for discussion purposes only:  Subject to Revision

## Planning Considerations 

**re: the MSL/ExoMars Cache**

- _Assume:_
- The MSL or ExoMars cache occupies 1/3 of the returned    sample volume/mass
- For MSL, the cache hardware design and how it will be used are as currently defined.
- _Questions:_
- What contribution to MSR’s possible scientific objectives is likely from these cached samples?
- If the MSL cache is recovered, what are the priorities for planning MSR’s capabilities to make use of the remaining 2/3 of the returned sample volume/mass?
- How would the priorities for MSR’s capabilities change if it returns to a previously visited site?

- Pre-decisional draft for discussion purposes only:  Subject to Revision

## Planning Considerations 

**Planning Considerations **
**re: the MSL/ExoMars Cache**

- Pre-decisional draft for discussion purposes only:  Subject to Revision

## Planning Considerations re: the MSL/ExoMars Cache

- The cached samples will have excellent field characterization     and context, but poor preservation and selectivity.
- For many of MSR’s geology-related objectives, significant progress can be made with cached samples.
- For most of MSR’s objectives sample encapsulation is judged to be essential for sample integrity, sample separation, and sample labeling (linkage to original field context).  The importance of having MSR collect additional samples to meet this need is very high.
- Several sample types of interest to MSR are not cache-able by MSL (drilled samples, regolith, dust, atmosphere, ice).

- _FINDING._  It is extremely important that MSR have the capability to select and acquire its own samples, even if the decision is made to recover a cache aboard the MSL or ExoMars spacecraft.

**Planning Considerations re: the MSL/ExoMars Cache**

- Pre-decisional draft for discussion purposes only:  Subject to Revision

## Surface Operations

- If MSR goes to a site that has not previously been visited, a relatively capable rover would be required.  Need more time and instruments.
- Caching of 1 sample is thought to take 5 days.  Thus, 100 days on the surface is too brief.
- It took 60 sols for Opportunity to evaluate Eagle Crater, 1 year for Endurance

- _FINDING._  The collection of suites of rocks requires significant surface mobility, the capability to assess the diversity of surface materials, and the ability to select samples that span that variation.     A minimum duration for surface operations of at least 6 - 12 months duration is anticipated, depending on landing site geography and geology.

- Pre-decisional draft for discussion purposes only:  Subject to Revision

## MSR and Special Regions

- How important is it to hold open the option of sending MSR to              a _planetary protection "special region"_?

- _FINDINGS_.
- ND-SAG finds that a scientifically compelling first MSR mission can be designed without including the capability to access and sample a special region.
- Although it would be desirable scientifically to retain the option of responding to a post-2007 discovery that changes our understanding of Martian special regions, this is neither affordable nor necessary for the first sample return.
- Based on our understanding of Mars as of 2007, unless MSR has the ability to land pole-ward of 30 degrees latitude, access very rough terrain, or achieve a significant subsurface penetration (e.g., >5 m), MSR is unlikely to be able to make use of incremental special regions capability.

- Pre-decisional draft for discussion purposes only:  Subject to Revision

## Summary of the 

**logic of this 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
- What subset of the above is the minimum required to define a scientifically compelling first MSR?
- Next steps: engineering, costs, consensus

- Pre-decisional draft for discussion purposes only:  Subject to Revision

## Envisioning the First MSR Mission:Parameters in the Trade Space

- Envisioning the First MSR Mission:Parameters in the Trade Space

- Pre-decisional draft for discussion purposes only:  Subject to Revision

## End

## A PP Question

- The draft test protocol estimates a need for 15-25 g       of material to complete the specified tests.  Two implementation options:
- Take 1-2 g from each of ~20 samples, prepare a composite sample, run the composite through the protocol.
- Would not give specific information about any single sample
- Collect two 25 g samples (regolith?), take 15 g from each for PP tests, don’t subsample all rocks
- Regolith will contain a mixture of contributions from local and remote sources.

- Pre-decisional draft for discussion purposes only:  Subject to Revision

## Sample Packaging Examples

- Examples of sample vials, bags used in the JSC meteorite lab.

**Sample Packaging Examples**

*Photos courtesy Kevin Righter*

- Pre-decisional draft for discussion purposes only:  Subject to Revision