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Astrobiology and habitability studies in preparation for future Mars missions: trends from investigating minerals, organics and biota
- P. Ehrenfreund, W.F.M. Röling, C.S. Thiel, R. Quinn, M.A. Sephton, C. Stoker, J.M. Kotler, S.O.L. Direito, Z. Martins, G.E. Orzechowska, R.D. Kidd, C.A van Sluis, B.H. Foing
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- Journal:
- International Journal of Astrobiology / Volume 10 / Issue 3 / July 2011
- Published online by Cambridge University Press:
- 12 May 2011, pp. 239-253
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Several robotic exploration missions will travel to Mars during this decade to investigate habitability and the possible presence of life. Field research at Mars analogue sites such as desert environments can provide important constraints for instrument calibration, landing site strategies and expected life detection targets. We have characterized the mineralogy, organic chemistry and microbiology of ten selected sample sites from the Utah desert in close vicinity to the Mars Desert Research Station (MDRS) during the EuroGeoMars 2009 campaign (organized by International Lunar Exploration Working Group (ILEWG), NASA Ames and ESA ESTEC). Compared with extremely arid deserts (such as the Atacama), organic and biological materials can be identified in a larger number of samples and subsequently be used to perform correlation studies. Among the important findings of this field research campaign are the diversity in the mineralogical composition of soil samples even when collected in close proximity, the low abundances of detectable polycyclic aromatic hydrocarbons (PAHs) and amino acids and the presence of biota of all three domains of life with significant heterogeneity. An extraordinary variety of putative extremophiles, mainly Bacteria and also Archaea and Eukarya was observed. The dominant factor in measurable bacterial abundance seems to be soil porosity and lower small (clay-sized) particle content. However, correlations between many measured parameters are difficult to establish. Field research conducted during the EuroGeoMars 2009 campaign shows that the geological history and depositional environment of the region, as well as the mineralogy influence the ability to detect compounds such as amino acids and DNA. Clays are known to strongly absorb and bind organic molecules often preventing extraction by even sophisticated laboratory methods. Our results indicate the need for further development and optimization of extraction procedures that release biological compounds from host matrices to enable the effective detection of biomarkers during future sampling campaigns on Earth and Mars.
Field astrobiology research in Moon–Mars analogue environments: instruments and methods
- B.H. Foing, C. Stoker, J. Zavaleta, P. Ehrenfreund, C. Thiel, P. Sarrazin, D. Blake, J. Page, V. Pletser, J. Hendrikse, S. Direito, J.M. Kotler, Z. Martins, G. Orzechowska, C. Gross, L. Wendt, J. Clarke, A.M. Borst, S.T.M. Peters, M.-B. Wilhelm, G.R. Davies, ILEWG EuroGeoMars 2009 Team
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- Journal:
- International Journal of Astrobiology / Volume 10 / Issue 3 / July 2011
- Published online by Cambridge University Press:
- 14 March 2011, pp. 141-160
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We describe the field demonstration of astrobiology instruments and research methods conducted in and from the Mars Desert Research Station (MDRS) in Utah during the EuroGeoMars campaign 2009 coordinated by ILEWG, ESA/ESTEC and NASA Ames, with the contribution of academic partners. We discuss the entire experimental approach from determining the geological context using remote sensing, in situ measurements, sorties with sample collection and characterization, analysis in the field laboratory, to the post sample analysis using advanced laboratory facilities.
We present the rationale for terrestrial field campaigns to strengthen astrobiology research and the link between in situ and orbital remote sensing data. These campaigns are supporting the preparation for future missions such as Mars Science Laboratory, ExoMars or Mars Sample Return. We describe the EuroGeoMars 2009 campaign conducted by MDRS crew 76 and 77, focused on the investigation of surface processes in their geological context. Special emphasis was placed on sample collection and pre-screening using in-situ portable instruments. Science investigations included geological and geochemical measurements as well as detection and diagnostic of water, oxidants, organic matter, minerals, volatiles and biota.
EuroGeoMars 2009 was an example of a Moon–Mars field research campaign dedicated to the demonstration of astrobiology instruments and a specific methodology of comprehensive measurements from selected sampling sites. We discuss in sequence: the campaign objectives and trade-off based on science, technical or operational constraints. This includes remote sensing data and maps, and geological context; the monitoring of environmental parameters; the geophysical context and mineralogy studies; geology and geomorphology investigations; geochemistry characterization and subsurface studies.
We describe sample handling (extraction and collection) methods, and the sample analysis of soils and rocks performed in the MDRS laboratory using close inspection, initial petrological characterization, microscopy, Visible-NIR spectrometry, Raman spectrometry, X-ray diffraction/X-ray fluorescence spectrometry, soil analysis, electrochemical and biological measurements.
The results from post-mission analysis of returned samples using advanced facilities in collaborator institutes are described in companion papers in this issue. We present examples of in-situ analysis, and describe an example investigation on the exploration and analysis of endolithic microbial mats (from reconnaissance, in-situ imaging, sampling, local analysis to post-mission sample analysis).
Analysis of mineral matrices of planetary soil analogues from the Utah Desert
- J.M. Kotler, R.C. Quinn, B.H. Foing, Z. Martins, P. Ehrenfreund
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- Journal:
- International Journal of Astrobiology / Volume 10 / Issue 3 / July 2011
- Published online by Cambridge University Press:
- 11 March 2011, pp. 221-229
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Phyllosilicate minerals and hydrated sulphate minerals have been positively identified on the surface of Mars. Studies conducted on Earth indicate that micro-organisms influence various geochemical and mineralogical transitions for the sulphate and phyllosilicate minerals. These minerals in turn provide key nutrients to micro-organisms and influence microbial ecology. Therefore, the presence of these minerals in astrobiology studies of Earth–Mars analogue environments could help scientists better understand the types and potential abundance of micro-organisms and/or biosignatures that may be encountered on Mars. Bulk X-ray diffraction of samples collected during the EuroGeoMars 2009 campaign from the Mancos Shale, the Morrison and the Dakota formations near the Mars Desert Research Station in Utah show variable but common sedimentary mineralogy with all samples containing quantities of hydrated sulphate minerals and/or phyllosilicates. Analysis of the clay fractions indicate that the phyllosilicates are interstratified illite–smectites with all samples showing marked changes in the diffraction pattern after ethylene glycol treatment and the characteristic appearance of a solvated peak at ∼17 Å. The smectite phases were identified as montmorillonite and nontronite using a combination of the X-ray diffraction data and Fourier–Transform Infrared Spectroscopy. The most common sulphate mineral in the samples is hydrated calcium sulphate (gypsum), although one sample contained detectable amounts of strontium sulphate (celestine). Carbonates detected in the samples are variable in composition and include pure calcium carbonate (calcite), magnesium-bearing calcium carbonate (dolomite), magnesium, iron and manganese-bearing calcium carbonate (ankerite) and iron carbonate (siderite). The results of these analyses when combined with organic extractions and biological analysis should help astrobiologists and planetary geologists better understand the potential relationships between mineralogy and microbiology for planetary missions.