JAXA schedules MMX Mars-moon sample-return launch for October 20
JAXA · NASA
JAXA set an October 20 launch date for its MMX Mars sample-return mission aboard H3 flight F10, carrying two NASA instruments.
updates
- 2026-10-16SpacePolicyOnline adds detail on MMX's two NASA instruments, the 15% US sample share, NASA's $87 million cost stake, and the mission's international partners.
what happened
JAXA announced August 20 that its Martian Moons eXploration (MMX) spacecraft is scheduled to launch October 20, 2026 at 4:41:03 JST aboard an H3 rocket, flight F10, from the Yoshinobu Launch Complex at Tanegashima Space Center. JAXA reserved a backup launch period of October 21 through November 7 in case the primary date slips, and said the exact launch time may vary within that window. The spacecraft will arrive at Mars in August 2027, collect a sample from the moon Phobos no earlier than December 2028, and return it to Earth in 2031, per SpacePolicyOnline. MMX carries two NASA instruments: MEGANE, a gamma-ray and neutron spectrometer from Johns Hopkins University's Applied Physics Laboratory, and P-Sampler, a pneumatic sample-collection device from Honeybee Robotics and Blue Origin that collected 13 grams of lunar regolith during a 2025 test on Firefly's Blue Ghost lunar lander. NASA will receive at least 15% of the returned Phobos sample for analysis and curation, at a 14-year lifecycle cost to the agency of $87 million, per SpacePolicyOnline. The mission also includes France's CNES, Germany's DLR and ESA, with the sample-return capsule landing in Australia.
why it matters
MMX will be H3's tenth flight and JAXA's first attempt at an interplanetary sample return, sending the vehicle out with a high-value payload after nine prior H3 missions. A clean launch keeps Japan's H3 manifest, which also carries commercial and government payloads, on the schedule JAXA has been rebuilding after the vehicle's earlier delays. NASA's two instruments and $87 million stake give the US planetary-science program a direct return on a foreign-led sample-return mission without funding a launch vehicle of its own, a model other agencies weighing partner-nation Mars missions will watch.
for who
Japanese launch-vehicle watchers and planetary science mission planners
signal-to-noise
quick facts
- Companies
- JAXA, NASA
- Category
- science
- Impact
- notable
- SNR
- 5 / 5
- Event date
- 2026-08-20
- Published
- 2026-08-20 05:32 UTC