Japan launches MMX mission to bring back the first samples from Mars' moon Phobos

Japan's space agency JAXA has launched its Martian Moons eXploration (MMX) mission, which aims to become the first to collect samples from Phobos, the larger of Mars' two moons, and return them to Earth.

The spacecraft lifted off on the 10th flight of Japan's H3 rocket from the Tanegashima Space Center at 4:41 am Japan time on Tuesday, October 20 (1:11 am IST). JAXA said the rocket performed as planned and that MMX separated from the upper stage about 71 minutes after launch, entering its intended trajectory towards Mars.

A decade-long round trip

MMX is expected to arrive in the Mars system in August 2027 after a cruise of about 10 months. It will enter a special orbit around Phobos, a lumpy body roughly 22 km across, and spend about three years studying it. Mission planners intend to map the surface, deploy a small rover called IDEFIX, and then make two brief touchdowns to gather material.

The spacecraft is designed to collect at least 10 grams of surface material using two systems: a coring device on a robotic arm and a pneumatic sampler that uses pressurised gas. It will also make several flybys of the smaller moon, Deimos, before heading home in late 2030. If all goes to plan, a return capsule will land in Australia in 2031.

International partners

The mission carries 13 scientific instruments. NASA contributed a gamma-ray and neutron spectrometer and the pneumatic sampler, and will receive a share of the returned material. The IDEFIX rover was developed by the French and German space agencies, CNES and DLR, and the European Space Agency is providing communications support.

Why it matters

Scientists remain divided over whether Phobos and Deimos are captured asteroids or debris from a giant impact on Mars. Samples could settle that question and shed light on how rocky planets formed. The mission also builds on Japan's success in returning asteroid samples with its Hayabusa probes, and is being closely watched in India, where ISRO has studied Mars and is planning further planetary missions.