Japan Launches MMX Mission to Retrieve Samples From Martian Moon Phobos

The Japan Aerospace Exploration Agency (JAXA) launched its Martian Moons eXploration (MMX) mission from the Tanegashima Space Center at 04:41:03 JST on October 20, 2026, sending an uncrewed probe on a five-year journey to collect and return soil from Phobos. The launch used an H3-24L rocket, marking the vehicle's first interplanetary mission.

The rocket's upper stage accelerated the 4,480-kilogram spacecraft to more than 24,000 mph to break Earth's orbit. Ground controllers have confirmed that MMX established contact, deployed its solar arrays, and remains in a stable condition. Industry reports estimate the mission's budget at $578 million.

Scientists aim to determine whether Phobos and Deimos are captured asteroids or debris from a massive impact on early Mars. "This is kind of like one of the major outstanding mysteries of solar system formation, the origin of Phobos and Deimos, so we really do need a mission like MMX to figure this out," said Dr. Daniel Glavin, a senior scientist at NASA's Goddard Space Flight Center.

JAXA leads the project in collaboration with NASA, the European Space Agency, the French space agency CNES, and the German Aerospace Center (DLR). The probe carries the French-German rover Idefix, which will be released from an altitude between 40 and 100 meters. The microgravity environment of Phobos allows the rover to rely on an unpowered drop rather than a dedicated descent propulsion system.

Orbital Arrival and Sampling Schedule

MMX is scheduled to reach Mars in August 2027 after a 10-month cruise, followed by a transfer into Phobos orbit in September 2027. Project timelines differ slightly on surface operations: JAXA documents schedule up to two landings in 2029, while ESA outlines target 2030 for sample collection. Controllers plan to gather at least 10 grams of regolith before the return module leaves Mars in late 2030, aiming for a capsule recovery at the Woomera Prohibited Area in South Australia in 2031.

Data gathered during the mission may also support long-term planning for deep-space transit, including the feasibility of using Phobos as a staging waypoint for crewed missions between Earth and Mars.