Initial results of the relative humidity observations by MEDA instrument onboard the Mars 2020 Perseverance Rover

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The Beagle 2 environmental sensors: intended measurements and scientific goals

The Beagle 2 lander, due for arrival on Mars in December 2003, carries an Environmental Sensors Suite to monitor the local meteorology and carry out simple dust and oxidant measurements. The suite is described, and the scientific goals are discussed

Humidity calibration of relative humidity devices in Martian conditions

Finnish Meteorological Institute (FMI) has developed relative humidity measurement devices for past and future Mars lander missions: REMS-H for Curiosity, MEDA HS for Mars 2020 and METEO-H for ExoMars 2020. The sensors used in these devices are HUMICAP® capacitive thin-film polymer sensors by Vaisala Inc. New calibration measurements are performed with ground reference models of these devices in the Mars Simulation Facility (MSF) and Planetary Analog Simulation Laboratory (PASLAB) at the German Aerospace Center (DLR) in spring 2020. The preliminary results will be given at the EGU 2020. Calibration of relative humidity devices requires in minimum two humidity points over the expected operational temperature and pressure range of the device. With two-point calibration the relative humidity devices can be used for scientific measurements with satisfactory quality but the uncertainty is notable. Stable humidity conditions between dry and saturation humidity in Martian conditions can be achieved reliably in very few laboratories in the whole world and humidity measurements in Martian conditions have been previously performed for the same devices in FMI laboratory and in Michigan Mars Environmental Chamber (MMEC) at the University of Michigan. The new measurement campaign will consist of stable humidity point measurements in multiple temperatures between +10°C to -70°C in CO2 gas and Martian pressure of approximately 7 hPa. The measurements are performed simultaneously for multiple devices in a small pressure vessel with continuous humidified carbon dioxide flow. The new measurement campaign will improve the characterization of the existing relative humidity devices in Mars lander missions and define in more detail the measurement uncertainties

The diverse meteorology of Jezero crater over the first 250 sols of Perseverance on Mars

NASA’s Perseverance rover’s Mars Environmental Dynamics Analyzer is collecting data at Jezero crater, characterizing the physical processes in the lowest layer of the Martian atmosphere. Here we present measurements from the instrument’s first 250 sols of operation, revealing a spatially and temporally variable meteorology at Jezero. We find that temperature measurements at four heights capture the response of the atmospheric surface layer to multiple phenomena. We observe the transition from a stable night-time thermal inversion to a daytime, highly turbulent convective regime, with large vertical thermal gradients. Measurement of multiple daily optical depths suggests aerosol concentrations are higher in the morning than in the afternoon. Measured wind patterns are driven mainly by local topography, with a small contribution from regional winds. Daily and seasonal variability of relative humidity shows a complex hydrologic cycle. These observations suggest that changes in some local surface properties, such as surface albedo and thermal inertia, play an influential role. On a larger scale, surface pressure measurements show typical signatures of gravity waves and baroclinic eddies in a part of the seasonal cycle previously characterized as low wave activity. These observations, both combined and simultaneous, unveil the diversity of processes driving change on today’s Martian surface at Jezero crater.This work has been funded by the Spanish Ministry of Economy and Competitiveness, through the projects no. ESP2014-54256-C4- 1-R (also -2-R, -3-R and -4-R); Ministry of Science, Innovation and Universities, projects no. ESP2016-79612-C3-1-R (also -2-R and -3-R); Ministry of Science and Innovation/State Agency of Research (10.13039/501100011033), projects no. ESP2016-80320-C2-1-R, RTI2018-098728-B-C31 (also -C32 and -C33), RTI2018-099825-B-C31, PID2019-109467GB-I00 and PRE2020-092562; Instituto Nacional de Técnica Aeroespacial; Ministry of Science and Innovation’s Centre for the Development of Industrial Technology; Spanish State Research Agency (AEI) Project MDM-2017-0737 Unidad de Excelencia “María de Maeztu”—Centro de Astrobiología; Grupos Gobierno Vasco IT1366- 19; and European Research Council Consolidator Grant no 818602. The US co-authors performed their work under sponsorship from NASA’s Mars 2020 project, from the Game Changing Development programme within the Space Technology Mission Directorate and from the Human Exploration and Operations Directorate. Part of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (80NM0018D0004). G.M. acknowledges JPL funding from USRA Contract Number 1638782. A.G.F. is supported by the European Research Council, Consolidator Grant no. 818602.Peer ReviewedPostprint (published version

Mars Science Laboratory relative humidity observations : Initial results

The authors would like to express their gratitude to the MSL and REMS instrument teams in making this wonderful Mars mission come true. Ari‐Matti Harri and Hannu Savijarvi are thankful for the Finnish Academy grants 132825 and 131723.Peer reviewedPublisher PD

Calibration and first results of relative humidity sensor MEDA HS onboard M2020 rover

MEDA HS is the relative humidity sensor on the Mars 2020 Perseverance rover provided by theFinnish Meteorological Institute (FMI). The sensor is a part of Mars Environmental DynamicAnalyzer (MEDA), a suite of environmental sensors provided by Centro de Astrobiología in Madrid,Spain. MEDA HS, along with METEO-H in ExoMars 2022 surface platform, is a successor of REMS-Hon board Curiosity.Calibration of relative humidity (RH) instruments for Mars missions is challenging due to the rangeof RH (from 0 to close to 100%) and temperature conditions (from about -90 ºC to + 22 ºC) thatneed to be simulated in the lab. Thermal gradients in different parts of the system need to be wellknown and controlled to ensure reliable reference RH readings. For MEDA HS the calibration testshave been performed for different models of MEDA HS in three Martian humidity simulatorlaboratories: FMI laboratory, Michigan Mars Environmental Chamber (MMEC) and DLR PASLAB(Planetary Analog Simulation Laboratory). MEDA HS flight model was tested at FMI together with flight spare and ground reference models inlow pressure dry CO2 gas from +22ºC to -70ºC and in saturation conditions from -40ºC down to-70ºC. Further, the MEDA HS flight model final calibration is complemented by calibration datatransferred from an identical ground reference model which has gone through rigorous testingalso after the flight model delivery. During the test campaign at DLR PASLAB that started inAutumn 2020, MEDA HS has been calibrated over the full relative humidity scale between -70 to-40ºC in CO2 in the pressure ranges from 5.5 to 9.5 hPa, representative of Martian surfaceatmospheric pressure. The results can be extrapolated to higher and lower temperatures.In this presentation the final flight calibration and performance of the MEDA HS will be presentedtogether with first results expected from the surface of Mars by the Perseverance rover

Pressure observations by the curiosity rover : Initial results

The authors would like to express their gratitude to the MSL and REMS instrument teams in making this wonderful Mars mission come true. Ari-Matti Harri and Hannu Savijarvi are thankful for the Finnish Academy grants 132825 and 131723.Peer reviewedPublisher PD

Mars 2020 Perseverance Rover Studies of the Martian Atmosphere Over Jezero From Pressure Measurements

The pressure sensors on Mars rover Perseverance measure the pressure field in the Jezero crater on regular hourly basis starting in sol 15 after landing. The present study extends up to sol 460 encompassing the range of solar longitudes from Ls ∼ 13°–241° (Martian Year (MY) 36). The data show the changing daily pressure cycle, the sol-to-sol seasonal evolution of the mean pressure field driven by the CO2 sublimation and deposition cycle at the poles, the characterization of up to six components of the atmospheric tides and their relationship to dust content in the atmosphere. They also show the presence of wave disturbances with periods 2–5 sols, exploring their baroclinic nature, short period oscillations (mainly at night-time) in the range 8–24 min that we interpret as internal gravity waves, transient pressure drops with duration ∼1–150 s produced by vortices, and rapid turbulent fluctuations. We also analyze the effects on pressure measurements produced by a regional dust storm over Jezero at Ls ∼ 155°.The UPV/EHU team (Spain) is supported by Grant PID2019-109467GB-I00 funded by 1042 MCIN/AEI/10.13039/501100011033/ and by Groups Gobierno Vasco IT1742-22. GM wants to acknowledge JPL funding from USRA Contract Number 1638782. A. Vicente-Retortillo is supported by the Spanish State Research Agency (AEI) Project No. MDM-2017-0737 Unidad de Excelencia “María de Maeztu”- Centro de Astrobiología (INTA-CSIC). Part of the research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (80NM0018D0004). GM wants to acknowledge JPL funding from USRA Contract Number 1638782

Convective Vortices and Dust Devils Detected and Characterized by Mars 2020

We characterize vortex and dust devils (DDs) at Jezero from pressure and winds obtained with the Mars Environmental Dynamics Analyzer (MEDA) instrument on Mars 2020 over 415 Martian days (sols) (Ls = 6°–213°). Vortices are abundant (4.9 per sol with pressure drops >0.5 Pa correcting from gaps in coverage) and they peak at noon. At least one in every five vortices carries dust, and 75% of all vortices with Δp > 2.0 Pa are dusty. Seasonal variability was small but DDs were abundant during a dust storm (Ls = 152°–156°). Vortices are more frequent and intense over terrains with lower thermal inertia favoring high daytime surface-to-air temperature gradients. We fit measurements of winds and pressure during DD encounters to models of vortices. We obtain vortex diameters that range from 5 to 135 m with a mean of 20 m, and from the frequency of close encounters we estimate a DD activity of 2.0–3.0 DDs km−2 sol−1. A comparison of MEDA observations with a Large Eddy Simulation of Jezero at Ls = 45° produces a similar result. Three 100-m size DDs passed within 30 m of the rover from what we estimate that the activity of DDs with diameters >100 m is 0.1 DDs km−2sol−1, implying that dust lifting is dominated by the largest vortices in Jezero. At least one vortex had a central pressure drop of 9.0 Pa and internal winds of 25 ms−1. The MEDA wind sensors were partially damaged during two DD encounters whose characteristics we elaborate in detail.The authors are very grateful to the entire Mars 2020 science operations team. The authors would also like to thank Lori Fenton and an anonymous reviewer for many suggestions that greatly improved the manuscript. This work was supported by Grant PID2019-109467GB-I00 funded by MCIN/AEI/10.13039/501100011033/ and by Grupos Gobierno Vasco IT1742-22 and by the Spanish National Research, Development and Innovation Program, through the Grants RTI2018-099825-B-C31, ESP2016-80320-C2-1-R, and ESP2014-54256-C4-3-R. Baptiste Chide is supported by the Director's Postdoctoral Fellowship from the Los Alamos National Laboratory. M. Lemmon is supported by contract 15-712 from Arizona State University and 1607215 from Caltech-JPL. R. Lorenz was supported by JPL contract 1655893. Germán Martínez acknowledges JPL funding from USRA Contract Number 1638782. A. Munguira was supported by Grant PRE2020-092562 funded by MCIN/AEI and by “ESF Investing in your future.” A. Vicente-Retortillo is supported by the Spanish State Research Agency (AEI) Project No. MDM-2017-0737 Unidad de Excelencia “María de Maeztu”-Centro de Astrobiología (INTA-CSIC), and by the Comunidad de Madrid Project S2018/NMT-4291 (TEC2SPACE-CM). Part of the research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (80NM0018D0004). Finnish researchers acknowledge the Academy of Finland Grant 328 310529. Researchers based in France acknowledge support from the CNES for their work on Perseverance