Idefix (rover)

Did You Know?

• The rover is named after Idéfix, the French name for Dogmatix, Obelix's dog in the Asterix comics.
• The name was chosen at the 2023 Paris Air Show to connect it with the first French satellite, Asterix.
• Idefix is not the first mini-rover: Franco-German MASCOT flew on Hayabusa2, and ESA/DLR Philae flew on Rosetta.

Operations

Idefix is a rover built through a partnership between France and Germany. Germany's DLR provided the rover's structure, its locomotion system, connectors for the MMX spacecraft, a spectrometer, and a radiometer. France's CNES supplied the cameras, computer, power system, and communication gear. The rover is controlled from two centers, one in Toulouse and one in Cologne. During the trip to Phobos, these centers take turns managing flight events. Once on the surface, they work in parallel, swapping roles weekly: one center runs current operations while the other plans the next seven days of activities. All commands and data travel through the MMX spacecraft and JAXA's ground station in Sagamihara; there is no direct link between Earth and the rover. The rover contacts the spacecraft twice each Earth day. Assembly and testing happened in Toulouse, and in 2024 the rover was shipped to Japan to be joined with the MMX spacecraft.

Locomotion system

The rover’s locomotion system, LOCO, is built to handle Phobos’s gravity, which ranges from 0.0030 to 0.0068 m/s². No matter how it lands, LOCO will flip the rover upright. Four wheels, each with nine blades called grousers, work on both hard ground and sand. A single wheel weighs just 190 grams and uses a mesh-like frame shaped by topology optimisation. LOCO has four modes: driving, alignment, uprighting, and passthrough. Autonomous navigation software was created by DLR and CNES, but at first the rover will move only after Earth sends driving plans.

Instruments

The Raman spectrometer for MMX (RAX) was developed by DLR, INTA/UVA and JAXA/UTOPS/Rikkyo. RAX uses a green Nd:YAG laser for excitation, analyzes a 50 μm area, collects backscattered light, filters out Rayleigh light, and guides remaining photons into a CMOS detector. It includes a verification target of deuteriated polyethylene terephthalate (PET) pellet. RAX operates in a spectral range of 535 to 680 nm, detecting a wide variety of minerals and identifying both primary and altered mineral phases. The miniaturized radiometer (miniRAD) measures infrared radiative flux to determine surface temperature. It uses thermophile sensors, is mounted on the rover's front, and has heritage from the Rosetta MUPUS thermal mapper, MASCOT radiometer, and InSight radiometer. miniRAD has six sensors with a 45-degree field of view, observing objects 25 to 150 cm away. The WheelCams are a pair of downward-facing panchromatic microcameras on the rover's underside, built around 2048×2048 CASPEX (CMV4000) sensors. They achieve ~100 μm/pixel at ~30 cm standoff and focus from roughly 20–50 cm. Each camera has co-located LEDs: four white sources and three narrow-band emitters at 590, 720, and 880 nm for multispectral snapshots. Operations include still and movie modes matched to the rover's slow traverse, with adaptive on-sensor binning to throttle data volume. Transparent shutters protect the optics until the rover completes its autonomous separation-landing-uprighting-deployment sequence.