Qu’est-ce que le projet MMX ?
Le MMX (Martian Moon eXploration) a pour but de concevoir un spectromètre pour la mission de la JAXA. MIRS (MMX InfraRed Spectrometer) est une nouvelle mission consistant à ramener un échantillon de Phobos, planifié par JAXA (Japan Aerospace eXploration Agency). Les deux lunes de Mars sont seront étudiés avec le lancement d’une sonde estimé en 2024 pour un retour en 2029.
Les objectifs scientifiques majeurs de cette mission :
1. Déconstruire la polémique sur l’origine des lunes de Mars en les observant plus en détail grâce aux échantillons.
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2. To constrain processes for planetary formation and material transport in the region connecting the inner and outer solar systems.
3. To reveal evolutionary processes of the Martian system in the circum-Martian environments.
MIRS is an imaging spectrometer in the 0.9 – 3.6 micron spectral band with a spectral resolution better than 20 nm. The IFOV (field of view of a pixel) is 0.35 milli-radian and the total field of view is +/- 1.65 degrees. The signal-to-noise ratio is greater than 100 down to 3.2 µm in an integration time of less than 2 s. The detector has a dimension of 256 x 256 pixels with a pixel size of 30 microns. The total mass is less than 11.9 kg (including 20% margin), and the volume of the complete instrument is about 320 x 150 x 400 mm3.
MIRS is built at LESIA-Paris Observatory in collaboration with four other French laboratories (see the organization chart), collaboration and financial support of CNES and close collaboration with JAXA and MELCO.
Les objectifs scientifiques de MIRS
MIRS will characterize the surfaces of Phobos and Deimos and the atmospheric composition of Mars, by identifying characteristic spectral signatures in the near infrared. MIRS shall meet the mission requirements, in particular:
MIRS va analyser les surfaces de Phobos et de Deimos ainsi que la composition atmosphérique de Mars à l’aide d’un…….
1) Investigate the surface distribution of Phobos constituent materials. Hydrated and other minerals must be identified in relation to the topography and characterized spectroscopically at a ground resolution of 20 m over nearly the entire surface of the satellite, and at a spatial resolution of 1 m within 50 m of the sampling point.
MIRS will need to measure water (ice) content (absorption band at 3.0-3.2 μm), hydrated silicate minerals (characteristic absorption bands at 2.7-2.8 μm), and organic matter (3.3.-3.5 μm) over the entire surface.
2) Investigate the distribution of constituent materials of Deimos, from spectroscopic information; determine the distribution of hydrated minerals, and other minerals, with an horizontal spatial resolution of 100 m or better in relation with topography of characteristic areas on the moon’s surface.
3) Constrain dust and water transport processes near the Martian surface: continuous observations of dust storms, ice clouds, and water vapor will be conducted for mid- and low-latitudes from the high-altitude equatorial orbit during different seasons with 1-hour temporal resolution.
MIRS observations will determine the distribution of water vapor in atmospheric columns with a spatial resolution of 10 km, an absolute spectral radiometric accuracy of 10%, a relative spectral radiometric accuracy of 1%, and with a temporal resolution of less than 1 hour in selected low latitude areas. These observations will be made on successive days in different seasons.
MIRS will allow to study the composition of Phobos, Deimos and to characterize the temporal variations in the atmosphere of Mars. It will also be a fundamental instrument to contribute to the selection of the two sample collection sites on the surface of Phobos.