NASA’s Mars 2020 (M2020) rover mission includes a suite of sensors to monitor current environmental conditions near the surface of Mars and to constrain bulk aerosol properties from changes in atmospheric radiation at the surface. The Mars Environmental Dynamics Analyzer (MEDA) consists of a set of meteorological sensors including wind sensor, a barometer, a relative humidity sensor, a set of 5 thermocouples to measure atmospheric temperature at ∼1.5 m and ∼0.5 m above the surface, a set of thermopiles to characterize the thermal IR brightness temperatures of the surface and the lower atmosphere. MEDA adds a radiation and dust sensor to monitor the optical atmospheric properties that can be used to infer bulk aerosol physical properties such as particle size distribution, non-sphericity, and concentration. The MEDA package and its scientific purpose are described in this document as well as how it responded to the calibration tests and how it helps prepare for the human exploration of Mars. A comparison is also presented to previous environmental monitoring payloads landed on Mars on the Viking, Pathfinder, Phoenix, MSL, and InSight spacecraft.

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Direct numerical simulation and large-eddy simulation have been performed for a heated sphere at Reynolds numbers of Re " 1000 and Re " 10 4 , respectively.The Prandtl number for both simulations has been P r " 0.7. Measurements of the local and average Nusselt number are performed and compared with literature available experimental results. Average and front stagnation point Nusselt numbers increase with the Reynolds number, while the minimum value moves towards the sphere apex as the flow enters the sub-critical regime. Differences in both viscous and thermal boundary layers are observed, while the shape factor at Reynolds number Re " 10 4 behaves similarly to that observed in circular cylinders at comparable Reynolds numbers. It is shown that as the Reynolds number increases, the increase in turbulent kinetic energy promotes the entrainment of irrotational flow thus enhancing the temperature mixing in the zone.The near wake, between 5 ď x{D ď 15, spreads at a faster rate at Re " 1000 with a slope close to x{D 1{2 , while at Re " 10 4 it follows a trend close to x{D 1{3 .

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Abstract-The purpose of this paper is to show that sigmadelta controllers of dielectric charge can be analyzed using the tools of sliding mode controllers, in the infinite sampling frequency approximation. This allows to study the dynamics of the hidden state variables related to the charge in the dielectric, as well as the reachability and stability of the control method. Furthermore, it is also possible to explain the response of the control bitstream as a function of the dynamical model of the system. This approach not only provides insight into the dynamics of the charge controllers, understood as hybrid systems, it also simplifies the modelling and simulations of the system. dielectric charge control, sliding mode control, charge trapping, switched systems, hybrid systems

The objective of this paper is to show the first results obtained with a gas sensor made of Au-functionalized WO 3 nanoneedles working under a closed-loop control designed to reduce its time response. The average temperature applied to the sensor is modulated to keep constant the average surface potential of the sensing nanostructures. This is done by periodically monitoring the resistivity of the sensing layer and generating temperature waveforms that enforce the condition: constant resistivity of the sensing layer at a reference temperature.Changes induced by the target gases must be compensated by changes in the average temperature being applied to the sensing layer. This signal, the average temperature applied to the sensor, is the new sensor output.

Abstract-The objective of this paper is to analyze the dynamics of heat flow in thermal structures working under constant temperature operation. This analysis is made using the tools of sliding mode controllers. The theory is developed considering that the thermal system can be described using diffusive representation. The experimental corroboration has been made with a prototype of a wind sensor for Mars atmosphere being controlled by a thermal sigma-delta modulator.This sensor structure allows to analyze experimentally the timevarying case since changes in wind conditions imply changes in the corresponding thermal models. The diffusive symbols of the experimental structures have been obtained from openloop measurements in which pseudo-random binary sequences of heat are injected in the sensor. With the proposed approach it is possible to predict heat flux transient waveforms in many applications.