Connect instruments and international teams

Under JAXA’s leadership, international contributions to MMX serve different purposes. NASA’s MEGANE measures gamma rays and neutrons to investigate elemental composition. CNES provides MIRS, a near-infrared spectrometer for mineralogical observations. Elemental abundance and mineral structure are related but different: knowing which elements are present does not uniquely tell you how they are arranged into minerals.

An original analogy is a set of building blocks. Two objects can use the same counts of blocks yet arrange them differently. A list of ingredients and a description of structure therefore supply complementary evidence. In a real spectral analysis, calibration, viewing geometry and physical models also affect the interpretation. No instrument label eliminates those requirements.

The French-German Idefix rover carries cameras, the RAX Raman spectrometer and the miniRAD radiometer. These investigate terrain, mineralogy and thermal behavior close to the surface. The flight-model photograph was taken during integration in Japan and published in 2025. It documents hardware on Earth; its wheels do not demonstrate that a traverse on Phobos has occurred.

Idefix is planned to fall to the surface after release, settle, right itself and deploy its solar generator. Its low-gravity operations differ from ordinary driving on Earth. A test can isolate one requirement, such as surviving contact or deploying a mechanism. Passing that test is valuable evidence about that requirement, while a successful surface campaign still depends on the combined system and actual environment.

A reply cannot outrun the signal

CNES and DLR jointly supply Idefix, while ESA contributes deep-space communications equipment and ground support. Communications link the science instruments, spacecraft and teams, but signals cannot arrive instantly. Commands must account for energy, thermal limits and opportunities to exchange data. Local autonomous sequences are especially important during time-sensitive operations.

For an original exercise, take an Earth-spacecraft separation of 180 million kilometers and a signal speed of about 300,000 kilometers per second. One-way travel takes 600 seconds, or 10 minutes. A reply needs at least another 10 minutes, before processing or waiting for a contact opportunity. A controller watching a delayed image cannot provide immediate joystick corrections to an event unfolding at the spacecraft.