Update on the Atmospheric Composition Measurements by Curiosity: Three (Earth) Years on Mars

The Sample Analysis at Mars (SAM) instrument on Curiosity has conducted a survey of major (CO2) and minor (Ar, N2, O2, CO) components of the Mars atmosphere over the course of one and a half martian years in Gale Crater. Here we present the details on the volume mixing ratios of these atmospheric species, which have been monitored as a function of season, temperature, and pressure, in conjunction with meteorological measurements conducted by the Mars Science Laboratory (MSL) rover environmental monitoring station (REMS). We will present data on the relative mixing ratio of CO2, and the computed partial pressure, which shows a distinct trend with season as a result of CO2 transported to and from the poles, coinciding with changes in local atmospheric pressure. We will also present data on the mixing ratios of the non-condensable species, which show relatively small seasonal changes at the near-equatorial site of Curiosity. Where relevant, comparisons to orbital and ground-based observations, as well as previous in situ measurements, will be discussed. Results from landing through the most recent measurements on Mars will be presented to demonstrate seasonal reproducibility.