The Mars - Mass Spectrum Analyzer (M-MSA) on board the M-MATISSE mission

The "Mars Magnetosphere ATmosphere Ionosphere and Space-weather SciencE (M-MATISSE)" mission, downselected for ESA's Phase A M-class call, aims to explore how the Martian Magnetosphere-Ionosphere-Thermosphere (MIT) system responds to space weather and impacts Mars' lower atmosphere and surface. Utilizing two orbiters with specialized payloads, M-MATISSE will offer a unique dual-perspective to study the plasma environment from Mars' surface to space, marking the first comprehensive global analysis of the planet’s atmospheric dynamics. Both M-MATISSE spacecraft will have 6 instruments with high TRL and enough time and spatial resolution and accuracy to resolve the system dynamics. Among the various sensors, the Mars Mass Spectrum Analyzer (M-MSA) is the instrument dedicated to plasma the composition analysis. It consists of a couple of electrostatic deflectors to acquire a hemispherical field of view, and a top hat for the energy-per-charge analysis, followed by a time-of-flight (TOF) chamber to determine ion mass-per-charge. M-MSA is designed to characterize ions escaping from the Martian atmosphere and the processes of escape, as well as to measure the ions in the solar wind (from 2 eV/e up to 38 keV/e). A notable feature of M-MSA instrument is that the TOF chamber is polarized with a linear electric field, which results in isochronous TOFs and enhanced mass resolution (typically, m/Δm ≈ 40). In this presentation, we will describe the design and operating principles of M-MSA, along with its scientific objectives at Mars.