A test bed for driving on Phobos
Available online :
Two students in the second year of the Master of Science in Aerospace Engineering at ISAE-SUPAERO will present a brand-new testbed at the international Lunar and Planetary Science Conference next week.
Gerald Imhof and Laura Passoni, majoring in Space Systems and supervised by Dr. Naomi Murdoch and Cecily Sunday (SSPA/DEOS), have designed and built a single-wheel testbed that will be critical for the MMX rover and for understanding the surface of the Martian moon Phobos.
The Martian Moons eXploration (MMX) mission will be launched in 2024 by the Japanese Aerospace Exploration Agency (JAXA) to the two Martian satellites, Phobos and Deimos, with the objective to study the origin of these bodies.

During the MMX mission, a French (CNES) and German (DLR) rover will be deployed to the surface of Phobos. The surface of Phobos is expected to be covered by fine-grained regolith and its milli-gravity environment will make landing and operating the MMX rovers very challenging.
The MMX rover will be equipped with two WheelCams pointed at the rover wheels to study wheel-regolith interactions in low-gravity conditions. The testbed developed by the students, with the support of their supervisors, recreates the scene that the MMX rover will observe with the WheelCams during the mission.
The testbed is instrumented with multiple sensors allowing independent measurements to be made of the sinkage of the wheel into the soil, and the slippage (essentially the loss of traction) of the wheel.
These measurements will be used to validate the WheelCam image analysis techniques currently under development, as well as the numerical simulations carried out by C. Sunday during her PhD thesis.

Photo: The ISAE-SUPAERO MMX WheelCam testbed.
The upper figure shows the full test bed and the lower figures show images taken with the two cameras.