Compiled from reports by Starlust and Astronomy. See the original articles linked below.
Japan's space agency JAXA has sent its Martian Moons eXploration spacecraft, known as MMX, on its way to Mars. Starlust reported that an H3 rocket carried the probe from the Tanegashima Space Center on Tuesday, 20 October 2026, local time. According to Starlust, it was the tenth flight of the H3, and JAXA said the spacecraft reached its planned trajectory after separating from the rocket.
Astronomy, in a preview article published on 16 October, said the launch was scheduled for 19 October, and an editor's note added later said the mission had lifted off and was on its intended path. The two outlets therefore give the date differently, which matches the time difference between Japan and the United States.
Route and timetable
Astronomy reported that MMX should reach Mars in August 2027 and enter a quasi-satellite orbit around Phobos about a month afterwards. Starlust gave the same August 2027 arrival and said the spacecraft would study Phobos from that orbit while evaluating possible landing sites.
Both outlets describe a small rover called Idefix, built by German and French space agencies. Starlust said it will explore the surface before the main spacecraft lands and gathers about 10 grams of material. Astronomy said the rover is due to be dropped in early 2029, and that the main spacecraft is to touch down twice in 2030 to collect at least 10 grams of regolith, the loose surface material.
After that, according to Astronomy, the spacecraft will fly past Deimos, Mars' other moon, on its way home. Starlust said the mission will spend roughly three years in the Mars system after observing Phobos and then Deimos. Both outlets said the sample capsule is expected to land in Australia in 2031.
International contributions
Starlust listed several partners. NASA is providing the MEGANE gamma-ray and neutron spectrometer, Honeybee Robotics, a Blue Origin company, built the pneumatic sampler, and the European Space Agency is handling communications and science data processing. Astronomy said MMX is intended to be the first spacecraft both to land on Phobos and to return a sample from it, with NASA supplying science instruments.
Scientific questions
Astronomy wrote that scientists do not know whether Phobos and Deimos are captured asteroids or debris thrown up by a large impact on Mars. It said the mission aims to settle how the moons formed and to shed light on how Mars lost its thick atmosphere and surface water. Starlust likewise said the samples should help explain how Phobos became a moon of Mars, which could add to understanding of how the solar system evolved.
Astronomy also noted that earlier attempts to reach Phobos failed, including two Soviet probes in 1988 and 1989 and Russia's Phobos-Grunt in 2011. It quoted JAXA project manager Kawakatsu Yasuhiro as saying the moon is still "an unexplored frontier for humankind."
Sources
- JAXA's historic MMX mission lifts off towards Mars to bring back first-ever samples from Phobos (Starlust, 2026-10-20)
- Japan prepares to launch sample return mission to Phobos (Astronomy, 2026-10-16)
This article was compiled with AI assistance from the reports listed above and reviewed by GMA before publishing.