Mars is privileged target in planetary sciences, in particular because of the conservation of ancient grounds (-4.5, -3.7 billion years) on the highlands of the South, while the Earth was living its first moments. This interest has grown in recent years with the discovery of ancient deposits bearing various hydrated phases including phyllosilicates, which are minerals testifying to the presence of liquid water in a stable manner on time scales that could be compatible with the development of life.
The objective of the ExoMars mission of the European Space Agency (ESA) is to characterize this astrobiological potential. This mission includes an orbiter (Trace Gas Orbiter / TGO), launched in 2016 and currently in orbit around Mars, and a rover scheduled for launch in 2022.
The ExoMars rover will notably be equipped with a drill allowing it to collect samples down to a depth of 2 meters, where traces of life may have been preserved from the radiations.
The samples, once taken by means of the drill, will then be crushed before being distributed by a carousel (SPDS / Sample Preparation and Distribution System) to the various instruments of a small laboratory within the rover: the visible hyperspectral microscope / near-IR MicrOmega developed by the IAS, the RAMAN RLS spectrometer and MOMA (Mars Organic Molecule Analyzer), a mass spectrometer coupled to a gas chromatograph. MicrOmega will in particular have a central role in the analyzes of these samples due to its ability to characterize their mineralogical and molecular composition (organic compounds) at the grain scale.
Figure 1: MicrOmega / ExoMars instrument qualification model.
The covers have been removed which allows to see the different subsystems composing MicrOmega / ExoMars: on the left the cryogenic machine with the detector and on the right the sample illumination system
Figure 2: Functional diagram of the MicrOmega / ExoMars instrument