NASA outlined its contributions to Japan’s Martian Moons eXploration mission in a 15 October announcement. JAXA’s spacecraft is targeting a 20 October launch in Japan, with plans to investigate Phobos and Deimos and return material from Phobos.
US contributions include the MEGANE instrument for studying surface composition, a pneumatic sampling demonstration, communications support and participating researchers. The mission aims to help distinguish between theories that the moons are captured asteroids or remnants of a large impact on Mars.
The published plan envisages arrival at Mars in August 2027 and sample delivery to Earth in 2031. Those are mission targets. As of this edition’s 18 October research cutoff, the cited announcement describes an upcoming launch, not a completed flight.