Abundance and Isotopic Composition of Gases in the Martian Atmosphere from the Curiosity Rover

Paul R. Mahaffy*, Christopher R. Webster, Sushil K. Atreya, Heather Franz, Michael Wong, Pamela G. Conrad, Dan Harpold, John J. Jones, Laurie A. Leshin, Heidi Manning, Tobias Owen, Robert O. Pepin, Steven Squyres, Melissa Trainer, MSL Science Team

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

293 Citations (Scopus)


Volume mixing and isotope ratios secured with repeated atmospheric measurements taken with the Sample Analysis at Mars instrument suite on the Curiosity rover are: carbon dioxide (CO2), 0.960(±0.007); argon-40 (40Ar), 0.0193(±0.0001); nitrogen (N2), 0.0189(±0.0003); oxygen, 1.45(±0.09) × 10−3; carbon monoxide, < 1.0 × 10−3; and 40Ar/36Ar, 1.9(±0.3) × 103. The 40Ar/N2 ratio is 1.7 times greater and the 40Ar/36Ar ratio 1.6 times lower than values reported by the Viking Lander mass spectrometer in 1976, whereas other values are generally consistent with Viking and remote sensing observations. The 40Ar/36Ar ratio is consistent with martian meteoritic values, which provides additional strong support for a martian origin of these rocks. The isotopic signature δ13C from CO2 of ~45 per mil is independently measured with two instruments. This heavy isotope enrichment in carbon supports the hypothesis of substantial atmospheric loss.
Original languageEnglish
Pages (from-to)263-266
Number of pages4
Issue number6143
Publication statusPublished - 19 Jul 2013


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