Japan plans Phobos sample mission to investigate origins of Mars’s moons

Japan’s space agency Jaxa was targeting a Tuesday launch for its Martian Moons eXploration mission, according to the Guardian’s 18 October 2026 report. The spacecraft would travel aboard an H3 rocket, reach the Mars region around August 2027 and return samples from Phobos to Earth in 2031. Scientists hope the material will help establish whether Mars’s moons formed from impact debris or were captured asteroids.

The mission plan calls for collecting at least 10 grams of soil through two sampling attempts. A French-German rover would first survey the surface to guide landing-site selection. NASA and Japanese devices would gather surface and shallow underground material, with the return capsule expected to land in Australia before transfer to Japan.

Although dozens of missions have explored Mars since the 1960s, the source describes its moons as poorly understood and notes failed Russian attempts to reach Phobos. Jaxa officials expect some collected material to originate on Mars itself, giving the mission a potential role in investigating both the moon and its neighbouring planet.