MMX (Martian Moons eXploration)
What is MMX (Martian Moons eXploration)?
Probes & telescopes· Launch 2026 – Mars arrival 2027 – sample return 2031 (planned). JAXA's Martian Moons eXploration launches in 2026, reaches Mars in 2027, lands on Phobos to grab a sample and brings it home in 2031 — the first material ever returned from the Mars system. Replay the Earth–Mars transfer in the orbit view.
The orbit of MMX (Martian Moons eXploration) at this moment: https://nowsky.org/solar/orbit?fw=probe%3Ammx&sp=2.6 — replayed live, no login.
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.
Frequently asked
- When did MMX (Martian Moons eXploration) launch?
- 2026 (JAXA, H3 rocket).
- What is the next milestone for MMX (Martian Moons eXploration)?
- 1 Oct 2026 — MMX launch — Martian moon sample return.
- In one line, what is MMX (Martian Moons eXploration)?
- Probes & telescopes — JAXA's Martian Moons eXploration launches in 2026, reaches Mars in 2027, lands on Phobos to grab a sample and brings it home in 2031 — the first material ever returned from the Mars system.
IDEFIX, the rover that will roll across Phobos
MMX carries IDEFIX, a 25 kg rover built by France and Germany. Dropped onto Phobos before the lander takes its sample, it scouts the firmness of the surface and the state of the dust. With Phobos's gravity less than a two-thousandth of Earth's, a rolling rover could bounce off, so its wheel speed is limited to a few metres an hour and it is built to right itself if it flips.
The name comes from the little dog in the French comic Asterix — a contrast with Phobos and Deimos, which mean "fear" and "dread". It will be the first rover to drive on the surface of a moon beyond Earth, and its data will decide where the MMX spacecraft touches down and how it samples. The experience of Hayabusa2's small MINERVA rovers hopping across Ryugu underlies the design.
The mission in depth
MMX — Martian Moons eXploration — applies the sample-return know-how of JAXA's Hayabusa missions to the moons of Mars. Launching on an H3 rocket in 2026, it enters Mars orbit about a year later, studies Phobos from a quasi-satellite orbit, then lands to collect at least 10 grams of surface material. The return capsule re-enters Earth's atmosphere in 2031.
Phobos is a 22-km potato of a moon, and for decades scientists have argued whether it is debris from a giant impact on Mars or an asteroid captured from the belt. Isotope ratios in the sample will settle the question. With gravity only 1/2,000th of Earth's, the landing is closer to docking than touching down; a small German–French rover goes first to scout the surface. Deimos is observed on flybys.
Track MMX in the orbit view to see the geometry of a Hohmann transfer between the orbits of Earth and Mars. Move the date to launch and replay Earth running ahead of Mars while the spacecraft climbs to meet the planet on its outer orbit. Zoom in on Mars in the orbit view to see Phobos and Deimos. The launch date may change.
Related
Figures are representative approximations. Simulated positions use J2000 mean elements.