CNES and DLR space agencies develop in 4 years the IDEFIX® rover to be carried on the JAXA MMX probe to explore the Mars largest moon, Phobos. The rover is delivered to JAXA in 2024 for a lift off planned in 2026. After a jettisoning by the MMX JAXA probe to the Phobos surface from a low altitude, it autonomously uprights using its locomotion (legs and wheels) to drive on Phobos regolith soil and perform its scientific mission. The rover scientific objectives are to explore the Phobos soil using its infrared radiometer MiniRad and its Raman spectrometer with laser (RAX) as well as cameras to characterize the mechanical action to the wheels into the regolith. This lightweight rover of 29 kg in a 50 x 50 x 25 cm box powered by solar panels is designed, manufactured and tested with a “NanoSat” approach to limit costs and schedule as a demonstrator. It embarks a CubeSat heritage for electronics, some new technologies with low TRL as well as flight proven hardware. The high risk level associated to such a “new space” mission is assessed and drives the development plan and design choices especially for the thermal control subsystem. The thermal control on Phobos Martian moon is challenging due to dust, thermal environment (-130°C to +50°C) and the low heating power allocated (< 1W) to thermally control battery, avionics and motors. In addition, the thermal control of the rover is very sensitive to heat leaks especially through harnesses. Despite this thermal challenge, a reduced development plan is adopted for the thermal control system design both in terms of thermal analyses campaigns, testing, hardware and operations. Even if the thermal control system has to guarantee the good thermal health in operations, the technical expectations for analyses and testing are revised to fit to the development plan. For example, the thermal control hardware has to be reliable but as simple as possible. The uncertainties for thermal analyses are higher than usual space element even after the thermal balance test. Testing is also reduced to the minimum leading for example to a thermal balance test that covers only partially the sizing thermal cases or a TM model only focused on the most critical parts due to cost limits. A way to compensate this lack of tests or analyses is covered by sensitivity studies. This paper presents this IDEFIX® rover thermal control system and its performances expected in flight in the frame of the specific development plan driven by a “NanoSat” approach.


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    Title :

    Thermal control performances of a rover on Phobos Martian Moon with a nanosat approach


    Contributors:

    Conference:

    Small Satellites Systems and Services Symposium (4S 2024) ; 2024 ; Palma de Mallorca, Spain


    Published in:

    Proc. SPIE ; 13546


    Publication date :

    2025-03-20





    Type of media :

    Conference paper


    Type of material :

    Electronic Resource


    Language :

    English



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