MEDA HS: Relative humidity sensor for the Mars 2020 Perseverance rover

The Finnish Meteorological Institute (FMI) provides a relative humidity measurement sensor (HS) for NASA's Mars 2020 rover. is part of the Environmental Dynamic Analyzer (MEDA), suite environmental sensors provided by Spain's Centro de Astrobiología. main scientific goal to measure Martian atmosphere near surface and complement previous mission atmospheric measurements better understanding conditions hydrological cycle. Relative has been measured from previously Phoenix Curiosity. Compared on board Curiosity, MEDA HS based new version polymeric capacitive heads developed Vaisala. Calibration devices challenging methods have HS. test campaigns performed at FMI, University Michigan German Aerospace Center (DLR) in Berlin achieve best possible calibration. accuracy uncertainty calibration also analysed detail with VTT Technical Research Centre Finland. Assessment performance after landing confirms that successful, delivering high quality data science community.