The Japan Aerospace Exploration Agency (JAXA) launched its Martian Moons eXploration (MMX) spacecraft at 04:41 Japan Standard Time on October 20, 2026, from the Yoshinobu Launch Complex at Tanegashima Space Center in Kagoshima Prefecture, according to JAXA's official launch notice and a report by the news agency Jiji Press carried by Nippon.com.
The probe lifted off on an H3 rocket, the tenth flight of that launcher. About one hour and eleven minutes after liftoff, the rocket placed MMX into its planned trajectory, Nippon.com reported. Yasuhiro Kawakatsu, the MMX mission leader at JAXA's Institute of Space and Astronautical Science, said after the launch that "we have confirmed that the probe is in a stable condition," according to the same report.
Makoto Arita, the H3 project manager, said the team was pleased to have reached the first milestone of the MMX mission, Nippon.com reported.
What the mission aims to do
MMX is designed to visit both of Mars's small moons, Phobos and Deimos, and to bring back a physical sample from Phobos — something no previous mission to the Mars system has achieved, according to the European Space Agency (ESA), which is a partner on the mission.
According to JAXA's mission description, the probe is expected to enter Mars orbit in August 2027 and move into orbit around Phobos the following month. It will then spend more than a year observing the moon before deploying a rover in December 2028, after which it will attempt to collect at least 10 grams of surface material during two planned landing attempts in 2029. The spacecraft will also perform flybys of Deimos in 2030 before leaving the Mars system in November 2030 and returning samples to Earth in July 2031.
ESA's project scientist for MMX, Elliot Sefton-Nash, described the launch as successful, saying JAXA's H3 launcher performed well in sending the probe toward Mars, and that the team was preparing for the spacecraft's arrival at Mars next summer. ESA's Director of Science, Carole Mundell, congratulated JAXA and the MMX team on the launch.
International partners and a long-delayed launch
MMX is led by JAXA with contributions from France's space agency CNES, Germany's DLR, NASA and ESA, according to ESA's mission page. France and Germany jointly built a rover named Idefix that will carry radiometers and spectrometers to study Phobos's surface, per the German Wikipedia summary of the mission. ESA supplied deep-space communication equipment and ground-station support through its Estrack network, and ESA scientists are part of the mission's science team.
The mission was originally planned to launch in 2022 but was postponed twice, first to 2024 and then to 2026, because of delays in developing Japan's new H3 launch vehicle, according to the German Wikipedia article on the MMX mission. The H3's success rate has now reached 80 percent after three consecutive successful flights, Nippon.com reported, following earlier setbacks including a 2023 failure of the rocket's first test flight.
Key mission milestones
MMX mission timeline| Milestone | Expected date |
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| Launch | October 20, 2026 |
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| Mars orbit insertion | August 2027 |
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| Phobos orbit entry | September 2027 |
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| Rover deployment on Phobos | December 2028 |
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| Sample collection attempts (2 landings) | 2029 |
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| Deimos flybys | 2030 |
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| Departure from Mars system | November 2030 |
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| Sample return to Earth | July 2031 |
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Questions
- When did Japan launch the MMX mission?
- JAXA launched the Martian Moons eXploration probe on October 20, 2026, at 04:41 JST aboard an H3 rocket from Tanegashima Space Center, according to JAXA's launch notice and Nippon.com.
- What is MMX trying to achieve?
- The mission aims to orbit and study Phobos and Deimos, land a rover on Phobos, collect at least 10 grams of surface material, and return that sample to Earth — the first such sample-return attempt from a Martian moon, per ESA.
- When will the samples reach Earth?
- According to JAXA's mission timeline, MMX is expected to depart the Mars system in November 2030 and deliver samples to Earth in July 2031.
- Why was the launch delayed from its original 2022 date?
- The German Wikipedia entry on the mission states the launch was postponed twice — to 2024 and then 2026 — because of development problems with Japan's H3 rocket.
- Who are JAXA's partners on the MMX mission?
- JAXA leads the mission with contributions from France's CNES, Germany's DLR, NASA and ESA; France and Germany jointly built the Idefix rover that will land on Phobos, according to ESA and German Wikipedia sources.
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