JAXA Launches World's First Phobos Sample Return — SkimNews
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- JAXA will launch the Martian Moons eXploration (MMX) mission on Tuesday aboard Japan's new H3 rocket — the world's first attempt to return samples from Phobos, a 27km-wide potato-shaped moon orbiting Mars three times a day at roughly 6,000km.
- The spacecraft reaches the Mars region around August 2027, will spend about three years orbiting and sampling Phobos, and is scheduled to return to Earth in 2031, with the reentry capsule landing in Australia before transfer to Japan.
- NASA is contributing a pressurized-gas surface sampler and a gamma-ray instrument, the European Space Agency is supplying a deep-space communications device, and a French-German rover called Idefix will land on Phobos around 2029 for a 100-day scouting mission to pick the sampling site.
- JAXA scientists aim to collect at least 10g of soil across two touchdowns using both NASA's gas-lift and JAXA's pneumatic coring (to ~2cm depth) methods; about 0.1% of the returned material is expected to have originated from Mars itself.
- Principal investigator Kiyoshi Kuramoto said soil analysis will 'almost certainly' settle whether Phobos and Deimos are captured asteroids or debris from a giant impact on Mars, a question that has lingered since the 1960s.
- Project manager Yasuhiro Kawakatsu framed Phobos as the most important 'unclimbed mountain in the solar system' and a candidate staging base for future crewed Mars missions being pursued by the US, China, and others.
Why it matters: JAXA is staking out first-mover status in Martian-moon science after multiple failed Russian Phobos attempts, including a 2011 launch. A successful return in 2031 would give Japan exclusive physical samples to resolve whether Phobos is a captured asteroid or impact debris — a question NASA's Mars missions have never targeted. Kawakatsu explicitly tied the science to a second-order goal: positioning Phobos as a staging point for the US, China, and others now racing toward crewed Mars exploration.
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