An Energy Analyser for the Characterization of the Neutral and Ionized Upper Atmosphere of Mars

International audienceMars’ exosphere is populated with oxygen and hydrogen atoms essentially. These atoms are either thermal or suprathermal. The suprathermal population is essentially formed from two processes: the atmospheric sputtering by planetary pick-up ions and the dissociative recombination of O2+ ions in the ionosphere. Both processes contribute to the erosion of the Martian atmosphere. Measuring the energy of these suprathermal particles in the exosphere would provide key information regarding these mechanisms but also would represent the first direct measurement of Mars’ neutral escape rate and a crucial information to understand the history of Mars’ atmosphere. Ions and Neutral Energy Analyser (INEA) is an instrument able to measure the density, temperature and drift velocity of neutral and ionized atmospheric particles. In order to analyse the energetic structure of particles within the Martian exosphere, INEA’s performance will achieve an energy resolution better than 0.05 eV over a wide range of densities. INEA will also perform mass analysis with a resolution greater than 10.In this presentation, I will present the concept of the instrument, the expected performances based on a complete numerical model of the instrument and the results of a first set of experiments on key parts of the instrument