Methane, Organics, Oxidants, and Habitability of Mars: Prospects for the Mars Science Laboratory Measurements

Paper number

IAC-07-A5.I.-A3.I.B.03

Author

Prof. Sushil Atreya, University of Michigan, United States

Year

2007

Abstract

SUSHIL K. ATREYA (a) , PAUL R. MAHAFFY (b)
(a) University of Michigan, Ann Arbor, MI 48109-2143 USA
(b) Goddard Space Flight Center, Greenbelt, MD 20771, USA

The lack of detection of organics on the surface of Mars by the Viking Life Science Experiments was most likely due to the presence of a powerful oxidant, hydrogen peroxide. Conventional photochemistry produces little (20-40 ppbv) H2O2, however. On the other hand,  triboelectric process during the Martian dust devils and storms as well as in normal saltation could produce much greater H2O2 electrochemically. Surface oxidants could also shorten the lifetime of the only organic molecule, methane, ever detected on Mars. This may imply a larger source to explain the observed CH4 abundance [1]. Changes in other molecules such as ozone are also expected due to electrochemistry. We will discuss potential scenarios for producing methane on Mars, including chemical, hydrogeochemical, and biogenic sources, and the loss by oxidation and heterogeneous process to a reactive surface. Detailed and precise measurements of the composition including key isotopes of the atmosphere, surface subsurface, and the rock samples will be carried out with a GC-MS and a Tunable Laser Spectrometer on the SAM Suite (Sample Analysis at Mars) on NASA's 2009 Mars Science Laborator, in order to address the above questions of organics and to study habitability of Mars. [atreya@umich.edu, webpage for downloading pdf's: <http://umich.edu/~atreya>]
References
[1] Atreya, S.K., Mahaffy, P.R., Wong, A.S., 2006. Methane and related trace species on Mars – origin, loss, implications for life, and habitability, Planet Space Sci., 55, 358-369, and references cited therein.

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IAC-07-A5.I.-A3.I.B.03.pdf

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