MMX (Martian Moons eXploration)
What is MMX (Martian Moons eXploration)?
Probes & telescopes· Launch 2026 – Mars arrival 2027 – sample return 2031 (planned). JAXA's mission to land on Mars's moon Phobos and bring a sample home. It aims to launch in 2026, reach Mars in 2027 and return to Earth in 2031.
Mission timeline
Spacecraft specs
| Launch | 2026 (JAXA, H3 rocket) |
|---|---|
| Mars arrival | 2027 |
| Sample return | 2031 |
| Landing target | Phobos (22 km) |
Figures are representative approximations. Source: compiled from NASA and IAU public data.
IDEFIX, the little rover bound for Phobos
MMX carries a small rover called IDEFIX, built by France and Germany and weighing less than 30 kg. It will be set down on Phobos before the main spacecraft lands, acting as a scout to check how firm the ground is and what the dust is like. What it finds will help decide where and how the spacecraft touches down.
Where gravity is as weak as on Phobos, a wheel that turns even a little too fast can lift the rover off the ground. IDEFIX therefore moves very slowly, and it is designed to right itself if it tips over. Its name comes from the little dog in the French comic Asterix, a friendly contrast to Phobos and Deimos, whose names mean fear and dread.
The mission in depth
MMX stands for Martian Moons eXploration. Japan's space agency JAXA has already brought asteroid samples to Earth with its Hayabusa and Hayabusa2 missions. Now it plans to use that experience to collect soil from Phobos, a moon of Mars. Launch on an H3 rocket is planned for no earlier than October 2026, and the schedule may change.
Phobos is a potato-shaped moon about 22 km across. How it formed has long been debated. One idea is that it gathered from debris thrown up when something large hit Mars; the other is that it is an asteroid captured by Mars's gravity. Analysing the returned soil should show which idea is right.
After entering Mars orbit in 2027, the spacecraft will study Phobos up close, then land and collect at least 10 grams of material. Phobos's gravity is less than a thousandth of Earth's, so the landing is closer to docking with another spacecraft than to touching down. The capsule carrying the sample is due back on Earth in 2031.
Follow MMX in the orbit view to see it move from Earth's orbit out to Mars's. At departure Mars is ahead of Earth, and the spacecraft travels about halfway around the Sun to meet Mars where the planet arrives. Zoom in on Mars to see Phobos and Deimos as well.
Frequently asked
- When did MMX (Martian Moons eXploration) launch?
- MMX (Martian Moons eXploration) was launched on 2026 (JAXA, H3 rocket).
- In one line, what is MMX (Martian Moons eXploration)?
- Probes & telescopes — JAXA's mission to land on Mars's moon Phobos and bring a sample home.
- What can I see of MMX (Martian Moons eXploration) here?
- You can see its live position in the orbit view.
Related
Figures are representative approximations. Simulated positions use J2000 mean elements.