Japan Sets Precise Launch Time for MMX Mission to Mars' Moons

Japan’s space agency has set a precise launch time for one of its most closely watched deep-space missions, saying the Martian Moons eXploration spacecraft is scheduled to lift off at 4:41:03 a.m. on Oct. 20, Japan time, or 19:41:03 UTC on Oct. 19.

The mission, known as MMX, is to launch aboard H3 Launch Vehicle Flight No. 10 from the Yoshinobu Launch Complex at the Tanegashima Space Center in Kagoshima Prefecture, the Japan Aerospace Exploration Agency said Sunday. The announcement is a firm launch-time update for a mission already years in development.

MMX matters well beyond a routine launch schedule. JAXA describes it as the first planned sample-return mission from the Martian system, with the goal of studying Mars’ two small moons, Phobos and Deimos, and bringing material from Phobos back to Earth.

Scientists want MMX to help answer a long-running question about how the moons formed: whether they are captured asteroids or debris left behind by a giant impact on Mars. By observing both moons up close and analyzing a returned sample from Phobos, researchers hope to settle a debate that has persisted for decades.

“Despite their potential importance, Martian moons have never been fully investigated. They are known as the most important unclimbed mountains in the solar system,” MMX project manager Yasuhiro Kawakatsu said in earlier remarks quoted by AP News.

The mission is also notably international. While led by JAXA, MMX includes contributions from NASA, the European Space Agency, France’s CNES space agency and Germany’s DLR aerospace center, underscoring the broad scientific interest in the Martian moons.

The launch is significant for Japan’s space program, too, because it will fly on the H3, the country’s next-generation main launch vehicle. That gives the mission added importance beyond its science goals, linking a flagship planetary project with Japan’s effort to establish its new rocket as a regular workhorse for major missions.

Public mission timelines released by JAXA and ESA show MMX reaching Mars in 2027. The sample capsule is targeted to return to Earth in 2031, with landing planned at Woomera in South Australia. JAXA said backup launch opportunities begin Oct. 21 and extend into early November.