NASA outlined its role in Japan's Martian Moons eXploration mission on October 15, 2026, ahead of a planned launch to investigate Mars' moons and return material from Phobos to Earth.
The Japan Aerospace Exploration Agency, or JAXA, is targeting liftoff from Tanegashima Space Center at 3:41 p.m. EDT on October 19. That is 4:41 a.m. on October 20 in Japan.
The mission, known as MMX, will examine Phobos and Deimos. Scientists want to determine whether the moons formed from debris thrown into orbit by an impact on Mars or were asteroids captured by the planet, NASA program scientist Tom Statler said.
The U.S. agency is supplying MEGANE, an instrument designed to measure gamma rays and neutrons from Phobos to identify elements on its surface. That chemical information is intended to help researchers investigate the moon's origin.
The agency is also contributing a pneumatic sampler mounted on a landing leg. It uses pressurized nitrogen to gather loose material near the surface, while JAXA's separate coring sampler is designed to reach several inches deeper.
According to NASA's schedule, the spacecraft will reach Mars in August 2027. Collection from Phobos is planned for no earlier than December 2028, with the sample due back on Earth in 2031.
NASA expects to receive about 15% of the returned material for long-term storage and research at Johnson Space Center in Houston. Its other contributions include Deep Space Network communications and navigation support and funding for U.S. scientists on the mission team.