Ancient Mars, Modern Mars, Active Mars : Atmospheric composition measurements with Curiosity

Séminaire IPAG de Melissa Trainer (NASA Goddard Space Flight Center), jeudi 5 octobre 2017 à 11h00, salle Manuel Forestini IPAG

The Sample Analysis at Mars (SAM) instrument onboard the Mars Science Laboratory Curiosity rover measures the chemical composition of major atmospheric species in the vicinity of the rover through dedicated atmospheric inlets. The SAM Quadrupole Mass Spectrometer (QMS) has monitored the volume mixing ratios of the major atmospheric components in Gale Crater over a period of nearly three Mars years (5 Earth years) from landing. The unprecedented seasonal coverage and precision in mixing ratio determination provides valuable data for understanding the seasonal chemical and dynamics cycles. In addition, with the SAM QMS and gas enrichment systems, we have made precise measurements of the isotopic ratios of atmospheric noble gases, providing insight into the origin of Mars’ atmosphere and identifying signatures of global change on billion-year time scales. Finally, SAM’s Tunable Laser Spectrometer (TLS) has detected a consistent background level and occasional bursts of CH4 at the ppbv levels throughout the mission, teasing at ancient or modern processes that may lead to the generation and release of this potential biosignature. This presentation will recount the atmospheric campaigns conducted by the SAM instrument suite on Curisoity, addressing questions about Mars evolution from its ancient past through today, and will discuss the implications for our understanding of the red planet and whether it was ever habitable.