JAXA has scheduled the Martian Moons eXploration (MMX) spacecraft to launch on October 20, 2026, at 04:41:03 Japan Standard Time (JST). The European Space Agency (ESA) gives the same planned moment as 9:41 p.m. Central European Summer Time (CEST) on October 19. The launch is assigned to H3 Launch Vehicle flight No. 10 (H3 F10), departing from Yoshinobu Launch Complex at Tanegashima Space Center. JAXA’s launch schedule lists the exact time and site; ESA’s mission update gives the European time.
JAXA’s reserve launch period
JAXA has reserved October 21 through November 7, 2026, as an additional launch period and says the launch time may vary during that window. The scheduled October 20 departure remains the announced target.
What MMX plans to do at Mars’s moons
MMX is designed to study Phobos and Deimos, deploy the Idefix rover on Phobos, and collect material there for return to Earth. ESA’s planned timeline puts arrival at Mars in August 2027 and operations around Phobos beginning in September 2027. Idefix, which weighs 25 kilograms, is slated for deployment in early 2029 to analyze Phobos’s surface composition and texture and help prepare for the main spacecraft’s landing. The main spacecraft is planned to collect samples in 2030.
ESA says MMX aims to return at least 10 grams of Phobos material to Earth in 2031. The return capsule is planned to land in Australia, with the sample then transferred to Japan for extraction, cataloging and sharing with mission partners. The samples are intended to help researchers investigate competing ideas about the moons’ origins, including whether they were captured asteroids or formed from debris after a large impact.
