Japan launches MMX probe to bring back the first samples from Mars's moon Phobos
JAXA's Martian Moons eXploration spacecraft lifted off on an H3 rocket from Tanegashima. It is due at Mars in 2027 and aims to return Phobos soil to Earth in 2031.
At a glance
- Japan's MMX (Martian Moons eXploration) spacecraft launched on an H3 rocket from Tanegashima Space Center at 4:41am JST on Tuesday, October 20, 2026.
- It is planned to reach Mars in August 2027, study Phobos and Deimos, land on Phobos and collect at least 10 grams of soil.
- The samples are due back on Earth in 2031, landing in Australia like the Hayabusa missions' capsules.
- MMX carries 13 instruments, including NASA's MEGANE spectrometer and IDEFIX, a small rover built by France's CNES and Germany's DLR.
Japan has launched a bold mission to the moons of Mars. The Japan Aerospace Exploration Agency's (JAXA) Martian Moons eXploration (MMX) spacecraft lifted off on an H3 rocket from the Tanegashima Space Center at 4:41am Japan time on Tuesday, October 20, 2026 (12:41am in Pakistan). Its goal: bring back the first-ever samples from Phobos, the larger of Mars's two moons.
The mission at a glance
| Launch | October 20, 2026, 4:41am JST, Tanegashima, Japan |
| Rocket | H3 (Mitsubishi Heavy Industries) |
| Target | Phobos and Deimos, the two moons of Mars |
| Mars arrival | Planned for August 2027 |
| Phobos landing | Planned after arrival (no earlier than late 2028, according to recent mission timelines) |
| Sample goal | At least 10 grams of Phobos soil |
| Return to Earth | 2031, landing in Australia |
| Instruments | 13 |
Three historic firsts
If all goes to plan, MMX will be:
- the first spacecraft to orbit Phobos in a close "quasi-satellite" orbit;
- the first to collect samples from the surface of a Martian moon;
- the first to return to Earth from the Mars system.
How it will work
After arriving at Mars, MMX will study both moons from orbit and make several flybys of the smaller moon, Deimos. Before landing, it will drop a small four-wheeled rover, IDEFIX (about 25kg), built by France's space agency CNES and Germany's DLR, which will spend up to 100 hours scouting the surface.
MMX will then touch down and collect soil with two devices: JAXA's C-Sampler core drill and a NASA-supplied pneumatic P-Sampler on one landing leg. A capsule carrying the samples will be released on the way home and land in Australia in 2031 — the same approach used by JAXA's Hayabusa and Hayabusa2 asteroid missions.
An international team
| Partner | Contribution |
|---|---|
| JAXA (Japan) | Lead agency, spacecraft, cameras, sampling drill, most instruments |
| NASA (US) | MEGANE gamma-ray and neutron spectrometer; P-Sampler |
| CNES (France) and DLR (Germany) | IDEFIX rover; CNES infrared spectrometer and flight dynamics |
| ESA (Europe) | Deep-space communications hardware and ground station support |
ESA's MMX project scientist Elliot Sefton-Nash said the team was "now even more motivated to prepare for arrival at Mars next summer".
Why Phobos matters
Phobos is a small, potato-shaped moon about 22km across that orbits very close to Mars. Scientists still do not know where it came from: it may be a captured asteroid, or it may have formed from debris thrown up by a giant impact on Mars. Its soil may also contain material blasted off Mars itself over billions of years, offering a way to study the red planet without landing on it.
Why it matters
Japan is a leader in sample-return missions after Hayabusa2 brought back material from asteroid Ryugu in 2020. A successful MMX would strengthen Japan's position in deep-space exploration as the United States, China and Europe pursue their own Mars plans — including future missions to return samples from Mars's surface.
What happens next
MMX will spend the coming months checking its systems on the cruise to Mars. The next major milestone is arrival at Mars in 2027.
Questions people are asking
What is Japan's MMX mission?
Martian Moons eXploration (MMX) is a JAXA mission to study Mars's two moons, Phobos and Deimos, land on Phobos, collect soil samples and bring them back to Earth in 2031. It launched on October 20, 2026.
Why study Phobos?
Scientists do not know whether Mars's moons are captured asteroids or debris from a giant impact on Mars. Samples from Phobos could settle the question and reveal how Mars and the inner solar system formed.
Will MMX land on Mars?
No. MMX will orbit Mars and fly close to its moons. It will land only on Phobos, deploying a small rover first to scout the surface.
