Identification of morphological biosignatures in Martian analogue field specimens using in situ planetary instrumentation.
We have investigated how morphological biosignatures (i.e., features related to life) might be identified with an array of viable instruments within the framework of robotic planetary surface operations at Mars. This is the first time such an integrated lab-based study has been conducted that incorporates space-qualified instrumentation designed for combined in situ imaging, analysis, and geotechnics (sampling). Specimens were selected on the basis of feature morphology, scale, and analogy to Mars rocks. Two types of morphological criteria were considered: potential signatures of extinct life (fossilized microbial filaments) and of extant life (crypto-chasmoendolithic microorganisms). The materials originated from a variety of topical martian analogue localities on Earth, including impact craters, high-latitude deserts, and hydrothermal deposits. Our in situ payload included a stereo camera, microscope, Mössbauer spectrometer, and sampling device (all space-qualified units from Beagle 2), and an array of commercial instruments, including a multi-spectral imager, an X-ray spectrometer (calibrated to the Beagle 2 instrument), a micro-Raman spectrometer, and a bespoke (custom-designed) X-ray diffractometer. All experiments were conducted within the engineering constraints of in situ operations to generate realistic data and address the practical challenges of measurement. Our results demonstrate the importance of an integrated approach for this type of work. Each technique made a proportionate contribution to the overall effectiveness of our "pseudopayload" for biogenic assessment of samples yet highlighted a number of limitations of current space instrument technology for in situ astrobiology.
Pullan
Derek
D
Space Research Centre, Department of Physics and Astronomy, University of Leicester, Leicester, UK. dpu@star.le.ac.uk
Westall
Frances
F
Hofmann
Beda A
BA
Parnell
John
J
Cockell
Charles S
CS
Edwards
Howell G M
HG
Villar
Susana E Jorge
SE
Schröder
Christian
C
Cressey
Gordon
G
Marinangeli
Lucia
L
Richter
Lutz
L
Klingelhöfer
Göstar
G
D000569:Americas; D000864:Antarctic Regions; D002119:Calcium Carbonate / Q000737:chemistry; D002133:Calcium Sulfate / Q000737:chemistry; D018559:Exobiology / Q000295:instrumentation*; D019015:Geologic Sediments / Q000737:chemistry / Q000382:microbiology*; D005858:Germany; D058085:Iron Compounds / Q000737:chemistry; D018535:Mars; D008903:Minerals; D000069497:Origin of Life
D058085:Iron Compounds; D008903:Minerals; C094886:goethite; D002119:Calcium Carbonate; D002133:Calcium Sulfate