Water vapor at Jezero Crater, Mars

International audienceWater on Mars is of interest today to assess the current cycling of water in and out of the regolith, cycling of water on and off of the polar caps, and to understand the current habitability potential of Mars. The regolith at polar and non-polar latitudes is an important reservoir for water storage, and an important resource for human exploration, and exchange of water between the regolith and atmosphere may play an important role in the global water cycle. Understanding water on Mars today helps us model the water cycle during different epochs on Mars, during which there was much more liquid water present in the system and Mars may have been inhabited.Additional time coverage and an additional location on the surface of Mars provided by the Perseverance MEDA relative humidity measurements at Jezero crater help reveal the regional similarities and differences across Mars. In addition, the Perseverance SuperCam or TIRS instruments can be used with the MEDA measurements of relative humidity to detect frost formation [2], to assess diurnal changes in the near-surface water content, possibly due to subsurface exchange (e.g., [5-6, 1]) or consistent with surface frost [2], and to check whether the environmental conditions at the surface and in the near surface are compatible with the formation of liquid brines [3-4].We examine the water vapor in the Martian atmosphere in the vicinity of Jezero Crater, Mars, where the Perseverance Rover is currently operating and acquiring data. We place the new water measurements from the rover instruments into the broader context, relating measurements to those of orbiters and other landers