Discussion of science value of a Mars sample return

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MSR pages: MSR facility - Legal Issues - science value - Dissenting views on back contamination risks

Editor's note: This article needs attention. This is based on part of the original Planetary protection for a Mars sample return - is it best separated out or included - or transcluded?

The motivation for the mission is its value for science. So evaluating its science potential is an important part of the decision process about whether to carry out the mission or not.

There is a diversity of views on its science value..[1][2] [3][4][5]

Advantages for science of a Mars sample return[edit | hide | hide all]

The European Space Foundation report cites many advantages of a Mars sample return.[6]

"Through the study of a sample, researchers could make great progress in understanding the history of Mars, its volatiles and climate, its geological and geophysical history, and gain new insights into astrobiology. A Mars sample return has also been deemed an essential precursor to any human exploration missions to Mars

"Although some questions may be answered through in situ studies carried out by robotics on the Mars surface, returning a sample to Earth is desirable for several reasons:

  • Many experiments and their sample preparations will be too complex for an in situ robotic mission
  • Returning a sample allows for flexibility in dealing with the unknown and unexpected discoveries via new protocols, experiments and measurements
  • There are major limitations with regard to size and weight of instrumentation that can be flown
  • There is a significant communication delay to Mars, which impedes the ability to deal with emergencies
  • There is a much greater diversity in available instruments and an almost unlimited range of analytical techniques that can be applied on Earth
  • The ability to repeat experiments in multiple laboratories and confirm key results is available on Earth
  • Participation of entire analytical community is possible
  • There is the potential to propagate organisms if they are discovered

In addition to the above points, returning a Mars sample will bring enormous public excitement and engagement to space-related activities, along with pride and prestige to this accomplishment of mankind.

Recommendation of continued in situ study first - white paper for decadal review[edit | hide]

This is a white paper submitted for the decadal review by eight authors from the NASA Jet Propulsion Laboratory, the Scripps Institution of Oceanography, SETI Institute, NASA Ames Research Center and the University of California Berkeley.

These authors argue that we do not yet know enough to intelligently select samples for return. They recommend a "Follow the Nitrogen strategy for in situ exploration".

They recommend that a MSR should be delayed until unambiguous biomarkers are identified in prospective Mars samples. They argue that there is a risk that samples returned at our current level of understanding may in the worst case be "as ambiguous with respect to the search for life as ALH84001." [1] [7]

For return of biologically interesting samples, they require ability to identify, in situ:

  • Biomarkers and unequivocal biosignatures stable over geological timescales. Examples: ability to detect chirality, and primary amine distribution.
  • Samples suitable for preserving life, and of preserving organics without significant degradation over geological time periods. Examples: sulfates, haliites, clays and the polar layered deposits
  • Nitrogenous organic compounds
  • Minute trace amounts of organics

They also recommend:

  • Any extraction methods used must preserve the target organic molecules with low degradation
  • Drilling must be carried out to the greatest depth possible, to allow for greatest chance of success for detecting organics and biosignatures.

Paige 's view[edit | hide]

Paige raises similar concerns.[2] He refers to a 1996 study requested by Michael Meyer of NASA’s Exobiological Program Office.[8] This divided Mars exploration into five phases including:[2]

  • Phase 1. Global Reconnaissance, focusing on past and present role of water, and identification of sites for detailed study.
  • Phase 2. In-Situ Exploration of Promising Sites, focusing on geologic, mineralogic, elemental, and isotopic characteristics, abundance and distribution of volatile species and organic molecules.
  • Phase 3. Deployment of exobiologically-focused experiments, and search for biomarkers of formerly living organisms, and extant life.
  • Phase 4. Robotic Return of Martian Samples to Earth, to improve characterization of organic compounds, and verify any evidence for biomarkers and extant life discovered in Phase 3.
  • Phase 5. Human exploration for detailed scientific characterizations of sites of unusual biologic interest, or inaccessible to robotic exploration.

Paige reasons that Mars exploration is still in phases 1 and 2, and that we need to complete phase 3 before going on to phase 4.[2][9]

Suggested near future methods for selection of samples of biological interest[edit | hide]

Some of the decadal review white paper, and Paige's concerns (but not all) have been addressed by the Final report of the MSR End-to End International Science Analysis Group in 2011. They stress the importance of observations to understand the geological context, They also plan to include the ESA Pasteur payload (developed for ExoMars) which includes some life detection instruments. It will for instance able for instance to detect many specific molecules likely to be associated with past or present life, with its Life Marker Chip.[10][11][12]

The focus of this report was on missions they considered practical, so, unlike Jeffrey Bada's suggestion, they don't require deep drilling, and don't require the MSR to be delayed until unambiguous biosignatures are found.

"Finally, for the purposes of this study, the vision of the MSR Campaign was constrained by what was considered to be practical ... Thus, objectives that might require high latitudes, high elevations, deep (>2 m) drilling, and large sample masses, for example, were given lower priority. The intent was not to provide a prioritized list in the abstract, but one that could be used to guide a sample return campaign in the context of our current knowledge and expectations of future engineering and fiscal resources." [11]

Contamination of a returned sample by terrestrial DNA (Craig Venter)[edit | hide]

Craig Venter (famous for sequencing the human genome) is in process of developing a miniaturized gene sequencer small enough to fit on a rover to Mars. Craig Venter's view is that this is best done in situ on Mars.[3]

His motivation for this is that current gene sequencers are now so sensitive, that if a single micro-organism from Earth landed on the sample returned from Mars, it would ruin any experiments to test for presence of martian DNA on the sample.

Space Studies Board recommendations to avoid biological contamination of the returned sample[edit | hide]

The Space Studies Board raise similar concern but believe biological contamination of the returned sample can be avoided by suitable decontamination procedures. This is from the 2011 review of the Space Studies Board,[4]

It is possible that traces of life on Mars may be very rare and heterogeneously distributed, and the concentration of organics in the soil may be very low. Thus, it is essential to avoid biological contamination as well as organic contamination of Mars and of the collected samples.

Alternatives to a Mars sample return to Earth[edit | hide]

There are proposals to study the sample extensively on the surface of Mars. There are also proposals to return the sample to quarantine facilities in Mars orbit or to Earth orbit, either before or after study on the surface.

With most of these approaches, Mars sample return would be expected eventually. The timing depends on the approach. For instance with the Bada and Paige suggestions, sample return would occur once samples are found with clear evidence of present or past life, or evidence of biosignatures in the present or past. With the telerobotics approach, sample return is done to Earth after preliminary study in orbit around Mars.

Other approaches are suggested by Zubrin and Levin (of the ICAMSR) but will be left for the separate article devoted to their views.

Extensive study of the samples first on the Mars surface[edit | hide]

Exomars Urey Instruments

We have seen that several authors recommended in situ survey first and and Paige predicted that new instruments under development will make it possible to analyse rocks in situ on Mars, permitting a flexible approach where rovers can make new choices of targets of potential biological interest on the surface of Mars based on findings for the samples encountered earlier in the mission.[1][2]

This is list of a few of the instruments under development for future Mars missions that permit or will permit preliminary study of samples with greater sensitivity than any instruments currently in use on the rovers.

  • NASA Marshall Space Flight Center is leading a research effort to develop a Miniaturized Variable Pressure Scanning Electron Microscope (MVP-SEM) for future lunar and martian missions.[13]
  • Jonathan Rothberg, and J. Craig Venter, are separately developing solutions for sequencing alien DNA directly on the Martian surface itself.[14][15]
  • Levin is working on updated versions of the Labeled release instrument flown on Viking. For instance versions that rely on detecting chirality. This is of special interest because it can enable detection of life even if it is not based on standard life chemistry.[16]
  • The Urey Mars Organic and Oxidant Detector instrument for detection of biosignatures has been descoped, but was due to be flown on ExoMars in 2018. It is designed with much higher levels of sensitivity for biosignatures than any previous instruments[1][17][18]
  • Astrobionibbler

Vigorous study of the Mars surface instead of a sample return[edit | hide]

Dirk Schulze-Makuch has taken this view, that a vigorous continuing study of the Mars surface would be more beneficial than a MSR at the current stage of exploration of Mars, though for rather different reasons.

Dirk Schulze-Makuch's view that from an atrobiological standpoint, in-situ research is better and cheaper than MSR[edit | hide]

This view was given in an interview for space.com of astrobiologist Dirk Schulze-Makuch [19]

"I disagree with the high priority on sample return," said astrobiologist Dirk Schulze-Makuch of Washington State University in Pullman.

"Our in-situ [on-the-spot] capabilities are so much better nowadays than, let's say during Viking lander (1970s) times," Schulze-Makuch said. "We could address with an in-situ mission whether microbial life is present on Mars."

Sample return missions are so much more costly, Schulze-Makuch said, "and the only thing that would be advantageous, in my view, is to get an absolute age scale via radioactive dating of Martian rocks," Schulze-Makuch said, "but from an astrobiological viewpoint, [an] in-situ mission would be better and cheaper."

He (along with other researchers) has published his own proposal for a mission called BOLD to send many penetrator probes to Mars to sample it sub surface and seek signs of life [20][21][22]

Study via telepresence from Mars orbit, followed by return of the sample to Mars orbit[edit | hide]

Telerobotics exploration on Mars and Earth

During the “Exploration Telerobotics Symposium" in 2012 experts on telerobotics from industry, NASA and academics met to discuss telerobotics, and its applications to space exploration. Amongst other issues, particular attention was given to Mars missions and a Mars sample return.

They came to the conclusion that telerobotic approaches could permit direct study of the samples on the Mars surface via telepresence from Mars orbit, permitting rapid exploration and use of human cognition to take advantage of chance discoveries and feedback from the results obtained so far.[23]

They found that telepresence exploration of Mars has many advantages. The astronauts have near real-time control of the robots, and can respond immediately to discoveries. It also prevents contamination both ways and has mobility benefits as well.[24]

Return of the sample to orbit has the advantage that it permits analysis of the sample without delay, to detect volatiles that may be lost during a voyage home. This was the conclusion of a meeting of researchers at the NASA Goddard Space Flight Center in 2012. [25]

Telerobotics exploration of Mars

"One possible scenario for surface exploration of Mars via LLT could be the deployment of twin telerobotic rovers on the surface with high-definition visual tools to allow low-latency communication and rapidly adaptable operation from an on-orbit crew for field astrobiology. Such “tele-rovers” could be equipped with instruments for detailed in situ reconnaissance and capabilities for recovering and sending selected samples to the human-tended on-orbit spacecraft for preliminary screening by means of lab analysis by resident astronauts. In the case of samples of biological significance, very rapid encapsulation and recovery of the sample materials at the spacecraft in orbit are required and this is enabled by this approach. Most of the required technology already exists for terrestrial telerobotics exploration of Earth, although the TRL would have to be advanced and validated for operations on Mars"[23]

For more about exploration of Mars via telepresence, see Exploration of the surface from orbit, via telerobotics and telepresence

Decadal review conclusions in favour of near term Mars sample return[edit | hide]

Some researchers and mission planners have put forward strong advocacy for an early Mars sample return. In particular this was one of the main conclusions of the 2011 decadal survey, an extensive survey of the community of active planetary scientists carried out every ten years in the USA.

The 2011 survey strongly advocated a Mars Sample Return program as the top flagship mission, to be carried out in several stages (with the mission to Europa proposal second).

"The view expressed by the Mars community is that Mars science has reached the point where the most fundamental advances will come from study of returned samples."[26]

In this survey, it was descoped due to cost considerations but the science value was considered high.[27]

In favour of the value of sample return they cite results from previous sample returns and their analogues (e.g., of meteorites, the Moon, cometary dust, and the solar wind) and point out that the Martian meteorites known are from a limited range of rock types, so that carefully selected samples returned from Mars can greatly increase our understanding of the planet.[28]

These views were later summarizes as:[5]

The Mars community, in their inputs to the decadal survey, was emphatic in their view that a sample return mission is the logical next step in Mars exploration. Mars science has reached a level of sophistication that fundamental advances in addressing the important questions above will only come from analysis of returned samples.

In the summary of the final report of the Mars Program Planning Group in September 2012,[29] two main possibilities were considered:

  • Search for signs of past life with samples collected from a site identified using exising data and returned to Earth for analysis (pathways A1 and A2)
  • Sample Return commences only after in situ measurements and sampling of multiple sites and Science Community decision process as to which to return to Earth (pathway A3)

They comment that the first option (their pathways A1 or A2) is most directly responsive to the NRC Decadal Survey recommendations.

Anteus (1978)

See also[edit | hide]

References[edit | hide]

  1. 1.0 1.1 1.2 1.3 Jeffrey L. Bada, Andrew D. Aubrey, Frank J. Grunthaner, Michael Hecht, Richard Quinn, Richard Mathies, Aaron Zent, John H. Chalmers Seeking signs of life on mars: in situ investigations as prerequisites to sample return missions Independent Contribution to the Mars Decadal Survey Panel
  2. 2.0 2.1 2.2 2.3 2.4 Mars Exploration Strategies: Forget About Sample Return D. A. Paige, Dept. of Earth and Space Sciences, UCLA, Los Angeles, CA 90095
  3. 3.0 3.1 Genome Hunters Go After Martian DNA Antonio Regalado, Biomedicine News, MIT Technology Review, October 18, 2012
  4. 4.0 4.1 The Quarantine and Certification of Martian Samples National Academy Press (2002), Chapter 8, Conclusions and Recommendations (page 60)
  5. 5.0 5.1 Vision and Voyages for Planetary Science in the Decade 2013-2022 (PDF) (Report). 2013. The site will be selected on the basis of compelling evidence in the orbital data for aqueous processes and a geologic context for the environment (e.g., fluvial, lacustrine, or hydrothermal). The sample collection rover must have the necessary mobility and in situ capability to collect a diverse suite of samples based on stratigraphy, mineralogy, composition, and texture.83 Some biosignature detection, such as a first-order identification of carbon compounds, should be included, but it does not need to be highly sophisticated, because the samples will be studied in detail on Earth 
  6. European Science Foundation - Mars Sample Return backward contamination - strategic advice July, 2012, ISBN 978-2-918428-67-1 - see 2. From remote exploration to returning samples. (for more details of the document see abstract )
  7. Included quote to assist editors in verification of the paraphrase

    In this White Paper we argue that it is not yet time to start down the MSR path. We have by no means exhausted our quiver of tools, and we do not yet know enough to intelligently select samples for return. In the best possible scenario, advanced instrumentation will identify biomarkers and define for us the nature of the sample to be returned. In the worst scenario, we will mortgage the exploration program to return an arbitrary sample that proves to be as ambiguous with respect to the search for life as ALH84001.

    ...We argue here that when in situ methods have definitively identified biomarkers, or when all reasonable in situ technologies have been exhausted, it will be time for MSR. We are not yet at that crossroad.

    ...Over the last decade the development of the Urey instrument for organic and oxidant detection on Mars has succeeded in addressing many of the aspects of primary concern for effective detection of biosignatures on Mars

  8. Requested by Dr. Michael A. Meyer, Discipline Scientist “An Exobiological Strategy for Mars Exploration” Prepared by the Exobiology Program Office, NASA HQ
  9. To assist editors in verification of my paraphrase

    Simply put, from a scientific and technological standpoint, we are not at Phase 4 yet. We don’t know where to go on Mars to get the samples we need to answer the life on Mars question, nor do we know how to design and build the vehicles and systems we need to accomplish a successful sample return mission, especially within the current resources of the Mars program...

    The notion that the next site we land at must necessarily be the site that we go to collect the first set of returned samples has got to be discouraged if we are ever going to explore the true diversity of the planet and its environmental history....

    There will always be scientists with laboratories who will advocate that NASA provide them with Mars samples for them to analyze. The fact is, however, that we don’t yet have the technology to do this within acceptable levels of cost and risk. As we are able to attract more resources to the program, it is vital that we use them to in manner which maximizes program’s excitement and further increases its scientific integrity...

  10. Life Marker Chip Robot Space Explorers, Open University
  11. 11.0 11.1 Planning for Mars Returned Sample Science: Final report of the MSR End-to End International Science Analysis Group
  12. Cranfield Health Detecting life on mars and the life marker chip: Antibody assays for detecting organic molecules in Liquid extracts of martian samples Phd thesis, Supervisor: Professor David C. Cullen, January 2012
  13. Gaskin, J.A.; Jerman, G.; Gregory, D.; Sampson, A.R., Miniature Variable Pressure Scanning Electron Microscope for in-situ imaging & chemical analysis Aerospace Conference, 2012 IEEE , vol., no., pp.1,10, 3–10 March 2012 doi: 10.1109/AERO.2012.6187064
  14. Mars Sample Return Mission? Naaah… Just Beam Back Martian DNA
  15. Biomedicine News Genome Hunters Go After Martian DNA
  16. A. D. Anbar1 and G. V. Levin A CHIRAL LABELED RELEASE INSTRUMENT FOR IN SITU DETECTION OF EXTANT LIFE., Concepts and Approaches for Mars Exploration (2012)
  17. Andrew D. Aubrey,1 John H. Chalmers, Jeffrey L. Bada, Frank J. Grunthaner, Xenia Amashukeli, Peter Willis, Alison M. Skelley, Richard A. Mathies, Richard C. Quinn, Aaron P. Zent, Pascale Ehrenfreund, Ron Amundson, Daniel P. Glavin, Oliver Botta, Laurence Barron,1 Diana L. Blaney, Benton C. Clark,11 Max Coleman, Beda A. Hofmann,12 Jean-Luc Josset,1 Petra Rettberg, Sally Ride, François Robert, Mark A. Sephton, and Albert Yen1 The Urey Instrument: An Advanced In Situ Organic and Oxidant Detector for Mars Exploration ASTROBIOLOGY Volume 8, Number 3, 2008
  18. J.L. Bada ·P. Ehrenfreund ·F. Grunthaner ·D. Blaney ·M. Coleman · A. Farrington ·A. Yen ·R. Mathies·R. Amudson ·R. Quinn ·A. Zent·S. Ride · L. Barron ·O. Botta ·B. Clark ·D. Glavin ·B. Hofmann · J.L. Josset·P. Rettberg · F. Robert ·M. Sephton Urey: Mars Organic and Oxidant Detector Space Sci Rev (2008) 135: 269–279
  19. Future Mars Missions: Can Humans Trump Robots?
  20. Dirk Schulze-Makuch A Bold New Chance for Mars Exploration! Blog for Huff Post Science, 05/11/2012
  21. Astrobiologist Proposes Fleet of Probes to Seek Life On Mars: Sensors Would Punch Into Soil, Run Range of Tests, Science Daily, Apr. 23, 2012
  22. Dirk Schulze-Makuch, James N. Head, Joop M. Houtkooper, Michael Knoblauch, Roberto Furfaro, Wolfgang Fink, Alberto G. Fairén, Hojatollah Vali, S. Kelly Sears, Mike Daly, David Deamer, Holger Schmidt, Aaron R. Hawkins, Henry J. Sun, Darlene S.S. Lim, James Dohm, Louis N. Irwin, Alfonso F. Davila, Abel Mendez, Dale Andersen Biological Oxidant and Life Detection (BOLD) mission: A proposal for a mission to Mars Planetary and Space Science, Volume 67, Issue 1, July 2012, Pages 57-69, ISSN 0032-0633, http://dx.doi.org/10.1016/j.pss.2012.03.008.
  24. Space Exploration Enabled by Telepresence: Combining Science and Human Exploration Based on Findings from: “Exploration Telerobotics Symposium” May 2-3, 2012 NASA Goddard Space Flight Center]
  25. Space Exploration Via Telepresence: The Case for Synergy Between Science and Human Exploration, Findings and Observations from: “Exploration Telerobotics Symposium” May 2-3, 2012 NASA Goddard Space Flight Center
  26. Decadal Survey Video - see 36.00 - and 48.30 for the main Mars sample return sections
  27. Decadal Survery Executive Summary
  28. To assist editors with verification Some quotes from the survey report follow to show how highly the mission was valued in the survey:

    "A major accomplishment of the committee’s recommended program will be taking the first

    critical steps toward returning carefully selected samples from the surface of Mars. Mars is unique among the planets in having experienced processes comparable to those on Earth during its formation and evolution. Crucially, the martian surface preserves a record of earliest solar system history, on a planet with conditions that may have been similar to those on Earth when life emerged. It is now possible to select a site on Mars from which to collect samples that will address the question of whether the planet was ever an abode of life. The rocks from Mars that we have on Earth in the form of meteorites cannot provide an answer to this question. They are igneous rocks, whereas recent spacecraft observations have shown the occurrence on Mars of chemical sedimentary rocks of aqueous origin, and rocks that have been aqueously altered. It is these materials, none of which are found in meteorites, that provide the opportunity to study aqueous environments, potential prebiotic chemistry, and perhaps, the remains of early martian life."

    During the decade of 2013-2022, NASA should establish an aggressive, focused technology development and validation initiative to provide the capabilities required to complete the challenging MSR campaign

    Finally, searching for evidence of extant life at Mars with a limited suite of experiments, compounded by the uncertainty regarding the nature of possible martian life and issues of terrestrial contamination, would be difficult and carries very high scientific risk

    Experience based on previous studies (e.g., of meteorites, the Moon, cometary dust, and the solar wind) strongly supports the importance of sample analysis. Such a diversity of techniques, analysis over time, improvements in sensitivity, and new approaches available in terrestrial labs are expected to revolutionize our understanding of Mars in ways that simply cannot be done in situ or by remote sensing.

  29. Summary of the Final Report Mars Program Planning Group, 25 September 2012 MPPG

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