Optimizing Cold Resistance: The Thermal Design of the MMX Rover IDEFIX's Locomotion Subsystem for the Martian Moon Phobos



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2024 International Conference on Environmnetal Systems


The Martian Moon eXploration (MMX) mission, spearheaded by the Japan Aerospace Exploration Agency (JAXA) is set to launch in 2024. Its objectives are to conduct the first sample-return of the moon Phobos and collect further scientific data by observing the moon Deimos. The main goal is to understand the origin of both Martian moons. Within this mission, the MMX rover IDEFIX, a collaborative development of the French Centre National d'Éttudes Spatiales (CNES) and the German Aerospace Center (DLR), is designated to serve as a mobile scout and explore the surface of Phobos. Functioning in microgravity, it will perform on-site scientific measurements using various on-board instruments and contribute data for JAXA's sample collecting task. The locomotion subsystem (LSS) of the MMX rover, developed, built, and qualified by DLR's Robotics and Mechatronics Center (RMC), holds a pivotal role in achieving the rover's objectives. It is designed to conduct several high-level requirements, such as the uprighting of the rover after ballistic landing, alignment of the solar cells towards the sun, as well as offering different driving modes to interact with Phobos surface. To ensure the resilience of the LSS under demanding conditions, especially the harsh environment during the cruise phase and the extremely low temperatures of Phobos surface during the night, a comprehensive thermal design was developed. This includes strategies like utilizing an advanced heater zone design featuring double-layer heat foils, thermal straps, SLI foils and material coatings, as well as thermally isolate sensitive mechatronic subcomponents. The design was additionally optimized, e.g. by a careful choice of material combinations to address thermal expansion concerns, while taking precautions against cold welding, and the incorporation of spring elements to maintain preload forces. This paper offers a comprehensive examination of DLR RMC's design for addressing the thermal demands of the LSS in various mission phases.


Ralph Bayer, German Aerospace Center (DLR e.V.), Germany
Kaname Sasaki, German Aerospace Center (DLR e.V.), Germany
Viktor Langofer, German Aerospace Center (DLR e.V.), Germany
Erich Krämer, German Aerospace Center (DLR e.V.), Germany
Franz Hacker, German Aerospace Center (DLR e.V.), Germany
Maxime Chalon, German Aerospace Center (DLR e.V.), Germany
Stefan Barthelmes, German Aerospace Center (DLR e.V.), Germany
ICES102: Thermal Control for Planetary and Small Body Surface Missions
The 53rd International Conference on Environmental Systems was held in Louisville, Kentucky, USA, on 21 July 2024 through 25 July 2024.


Martian Moon eXploration (MMX), Sample-return mission, IDEFIX rover, MMX rover, Locomotion subsystem (LSS), Phobos, Thermal design, Microgravity exploration