NASA is supporting JAXA's Martian Moons eXploration (MMX) mission, which aims to characterize Mars' moons Phobos and Deimos, determine their origin and return a sample of Phobos to Earth, the agency said in an article published Oct. 15, 2026. The spacecraft was targeting launch from Tanegashima Space Center in Japan at 3:41 p.m. EDT on Monday, Oct. 19 (4:41 a.m. JST Tuesday, Oct. 20).

NASA's contributions include the MEGANE gamma-ray and neutron spectrograph, which will measure emissions from Phobos' surface to determine its chemical elemental composition, and the Pneumatic Sampler, a technology demonstration mounted on a landing leg that uses bursts of high-pressure nitrogen gas to gather surface material. NASA is also providing communications and navigation support through the Deep Space Network, funding U.S. scientists on the MMX science team, and will obtain and curate about 15% of the returned sample at Johnson Space Center in Houston.

Scientists have long debated whether the moons are debris from a massive impact on Mars or captured ancient asteroids. The spacecraft will arrive at Mars in 2027, survey Phobos in detail, collect a sample no earlier than 2028 and deliver it to Earth in 2031.