Mars Atmospheric Composition, Isotope Ratios and Seasonal Variations: Overview and Updates of the SAM Measurements at Gale Crater

Friday, 19 December 2014: 2:00 PM
Christopher R Webster1, Paul R Mahaffy2, Sushil K Atreya3, Pamela Gales Conrad2, Heather Franz2, Melissa G Trainer2, Michael H Wong4, Michael A Mischna1, Gregory Flesch1, Kenneth A Farley5, Tobias C Owen6, Paul B Niles7, John H Jones7, Lance E Christensen1, Javier Martín-Torres8 and Maria-Paz Zorzano9, (1)NASA Jet Propulsion Laboratory, Pasadena, CA, United States, (2)NASA Goddard Space Flight Center, Greenbelt, MD, United States, (3)University of Michigan Ann Arbor, Ann Arbor, MI, United States, (4)University of California, Berkeley, CA, United States, (5)California Institute of Technology, Pasadena, CA, United States, (6)Univ Hawaii, Honolulu, HI, United States, (7)NASA Johnson SFC, Houston, TX, United States, (8)Instituto Andaluz de Ciencias de la Tierra, Granada, Spain, (9)INTA-CSIC, Madrid, Spain
We will summarize the in situ measurements of atmospheric composition and the isotopic ratios of D/H in water, 13C/12C, 18O/16O, 17O/16O, and 13C18O/12C16O in carbon dioxide, 38Ar/36Ar, xKr/84Kr, and 15N/14N made in the martian atmosphere at Gale Crater from the Curiosity Rover using the Sample Analysis at Mars (SAM)’s Quadrupole Mass Spectrometer (QMS) and Tunable Laser Spectrometer (TLS). With data over 700 sols since the Curiosity landing, we will discuss evidence and implications for changes on seasonal and other timescales. We will also present results for continued methane and methane enrichment experiments over this time period. Comparison between our measurements in the modern atmosphere and those of martian meteorites like ALH 84001 implies that the martian reservoirs of CO2 and H2O were largely established ~4 billion years ago, but that atmospheric loss or surface interaction may be still ongoing.

[1] Mahaffy P. R. et al., Science, 341, 263-266, 2013, doi:10.1126/science.1237966.
[2] Webster C. R. et al. (2013), Science, 341, 260-263, doi:10.1126/science.1237961.
[3] Wong, M. H. et al. (2013), Geophys. Res. Lett., doi:10.1002/2013GL057840.
[4] Atreya S. K. et al (2013), Geophys. Res. Lett., 40, 15, doi:10.1002/2013GL057763.

The research described here was supported by the National Aeronautics and Space Administration (NASA).