Japan’s MMX mission is preparing to investigate whether Mars’ moons formed after a major impact or were captured asteroids. NASA’s contribution includes an instrument to measure surface elements and a sampler targeting loose material on Phobos. The planned measurements and sample return aim to distinguish the competing explanations; the mission has yet to launch.
Japan’s Martian Moons Exploration mission, MMX, aims to investigate how Phobos and Deimos, the two moons of Mars, formed. The mission plans to land on Phobos, collect surface material and return it to laboratories on Earth. Those samples are intended to help resolve an open question about the moons’ origins. The spacecraft is preparing for launch; its scientific results are still ahead.[1], [2]
NASA, the US space agency, described its contribution to the Japanese space agency JAXA’s mission on 15 October. Its MEGANE instrument is designed to examine Phobos’ elemental composition through gamma rays and neutrons emitted from the surface. Scientists are comparing two main explanations: ancient asteroids captured by Mars, or material thrown into orbit by a major impact. Elemental measurements are part of the planned investigation of those alternatives.[1]
NASA’s pneumatic P-Sampler targets loose surface material. JAXA’s C-Sampler is designed to reach deeper, giving the mission complementary ways to gather material from Phobos. NASA also provides communications and navigation assistance through its Deep Space Network, the ground-based network supporting distant spacecraft. The instruments and sampling systems describe how the mission intends to examine the moon; neither origin explanation has been confirmed by MMX observations.[1]
NASA gives 19 October as the launch target and August 2027 as the intended arrival at Mars. Sample collection is planned no earlier than December 2028, with delivery to Earth in 2031. The agency plans to curate about 15 per cent of the returned material at Johnson Space Center in Houston. These are scheduled mission stages, with sample analysis dependent on the spacecraft completing its journey and collection.[1]
