Japan's MMX mission to bring first samples from Martian moon Phobos

JAXA plans to launch the MMX probe on October 20, 2026, to collect at least 10 grams of material from Phobos and return it to Earth by 2031. The mission, supported by French and German space agencies via the IDEFIX rover, could settle how Mars' moons formed and test technologies for future Mars exploration.

Bottom line — MMX aims to return the first samples from a Martian moon by 2031, with European rover support.

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• The mission will launch aboard an H3 rocket from Tanegashima Space Center, per JAXA.
• The spacecraft weighs 4,480 kg at launch, with more than half of that fuel, according to TechSpot and WIRED.
• The IDEFIX rover, developed by CNES and DLR, will be deployed onto Phobos for about 100 days of surface reconnaissance before the main landing, per WIRED.
• Landing on Phobos is challenging due to its intermediate gravity — stronger than asteroid Ryugu but weaker than Earth's moon — requiring autonomous navigation with up to 20-minute communication delays, per TechSpot.
• Two competing hypotheses for the moons' origin exist: a giant impact on Mars or capture of asteroids from the outer Solar System, per JAXA and WIRED.
• The probe will use a robotic arm to drill cylindrical samples and a NASA-developed nitrogen-gas system to collect fine dust, per TechSpot.
• Scientists expect about 0.1% of the collected material to be Martian debris blasted onto Phobos by impacts, per WIRED.
• The mission cost is approximately €317 million ($345 million), per TechSpot and NHK.
• The sample return capsule is scheduled to be recovered in Australia, per JAXA and The Mainichi.

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