In Situ Analysis of Mars Soil and Rocks Sample with the Sam Gcms Instrumentation Onboard Curiosity : Interpretation and Comparison of Measurements Done during the First Martian Year of Curiosity on Mars

Thursday, 18 December 2014
Cyril Szopa1, Patrice J Coll2, Michel Cabane1, Arnaud Buch3, David Coscia1, Maeva Millan1, Pascaline Francois2, Imene Belmahadi3, Samuel Teinturier4, Rafael Navarro-Gonzalez5, Daniel Patrick Glavin4, Caroline Freissinet6, Andrew Steele7, Jennifer L Eigenbrode4 and Paul R Mahaffy8, (1)LATMOS Laboratoire Atmosphères, Milieux, Observations Spatiales, Paris Cedex 05, France, (2)LISA, Creteil Cedex, France, (3)LGPM Laboratoire Génie des Procédés et les Matériaux, Châtenay-Malabry Cedex, France, (4)NASA Goddard Space Flight Center, Greenbelt, MD, United States, (5)Universidad Nacional Autonoma de Mexico, Mexico City, Mexico, (6)NASA Goddard Space Flight Center, NASA Postdoctoral Program, Greenbelt, MD, United States, (7)Carnegie Institution for Science, Washington, DC, United States, (8)NASA Goddard SFC, Greenbelt, MD, United States
The characterisation of the chemical and mineralogical composition of solid surface samples collected with the Curiosity rover is a primary objective of the SAM experiment. These data should provide essential clues on the past habitability of Gale crater. Amongst the SAM suite of instruments [1], SAM-GC (Gas Chromatograph) is devoted to identify and quantify volatiles evolved from the thermal (heating up to about 900°C)/chemical (derivatization procedure) treatment of any soil sample collected by the Curiosity rover. With the aim to search for potential organic molecules outgassed from the samples, SAM-GC analytical channels composed of thermal-desorption injector, and a MXT-CLP or a MXT-Q chromatographic column was chosen to achieve all the measurements done up today, with the aim to separate of a wide range of volatile inorganic and organic molecules. Four solid samples have been analyzed with GCMS, one sand sample collected at the Rocknest site, two rock samples (John Klein and Cumberland respectively) collected at the Yellowknife Bay site using the Curiosity driller, and one rock sample collected at the Kimberly site.

All the measurements were successful and they produced complex chromatograms with both detectors used for SAM GC, i.e. a thermal conductivity detector and the SAM quandrupole mass spectrometer. Their interpretation already revealed the presence of an oxychlorine phase present in the sample which is at the origin of chlorohydrocarbons clearly identified [2] but this represents only a fraction of the GCMS signal recorded [3,4]. This work presents a systematic comparison of the GCMS measurements done for the different samples collected, supported by reference data obtained in laboratory with different spare models of the gas chromatograph, with the aim to bring new elements of interpretation of the SAM measurements.

References: [1] Mahaffy, P. et al. (2012) Space Sci Rev, 170, 401-478. [2] Glavin, D. et al. (2013), JGR. [3] Leshin L. et al. (2013), Science, [4] Ming D. et al. (2013), Science, 32, 64–67.

Acknowledgements: SAM-GC team acknowledges support from the French Space Agency (CNES), French National Programme of Planetology (PNP), National French Council (CNRS), Pierre Simon Laplace Institute, Institut Universitaire de France (IUF) and ESEP Labex, and the great MSL team