On-ground calibration and performance evaluation of MMX InfraRed spectrometer (MIRS) for the Martian moon eXploration mission: Setup development, data acquisition, and preliminary results

The MMX InfraRed Spectrometer (MIRS) is a spectro-imager on board the Japan Aerospace Exploration Agency Martian Moons eXploration mission, set to launch in 2026, to investigate the origin of the Martian moons, Phobos and Deimos, as well as the Martian atmosphere and surface. MIRS, operating in the 0.9-3.6 μm wavelength range, is designed to identify and map minerals, ices, and organic compounds on the Martian moons, while also monitoring water vapor and dust in Mars's atmosphere. This paper details the ground calibration and performance evaluation of the MIRS Flight Model, conducted at the Laboratory for Instrumentation and Research in Astrophysics at the Paris Observatory during the thermal-vacuum test campaign at the end of 2023. A detailed description of the apparatus and the procedures used during the campaign is provided. The calibration campaign tested the instrument's thermal response and radiometric performance, ensuring compliance with stringent mission requirements. The tests demonstrated MIRS's capability to deliver high-resolution spectral data, fulfilling critical scientific and technical objectives. The preliminary results indicate MIRS's readiness for in-flight operations and its potential to contribute significantly to the understanding of the Mars system.