Japan’s MMX mission will sample Phobos and return material to Earth in 2031
JAXA’s Martian Moons eXploration mission is scheduled to launch on 20 October 2026 and collect samples from Phobos, Mars’s larger moon. The spacecraft will study both moons, with a small French-German rover due to survey Phobos before the lander attempts one or two sample collections; the material is expected back on Earth in 2031.
Bottom line — MMX aims to return more than 10 grams from Phobos, where samples could help distinguish between competing theories of the moon’s origin.
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JAXA says MMX is the first mission designed to return samples from the Martian system.
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The mission will test whether Phobos formed from debris after a major impact on Mars or was captured as an asteroid.
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According to DLR, Phobos’s surface spectra point towards captured asteroids, while the moons’ orbits favour an impact origin.
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The Idefix rover, contributed by France’s CNES and Germany’s DLR, will examine Phobos’s surface and help assess a landing site.
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JAXA’s plan includes a coring sampler for material below the surface and a pneumatic sampler for loose grit.
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NASA is contributing MEGANE, an instrument that will measure gamma rays and neutrons to assess Phobos’s chemical composition.
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DLR says a portion of the returned samples is to be transferred to Europe for joint curation by German and French agencies.