A Japanese spacecraft lifted off Tuesday on an unprecedented voyage to the Martian system, aiming to land on the moon Phobos and return the first-ever samples from the Red Planet’s vicinity. The Martian Moons Exploration (MMX) mission, a collaboration among five space agencies, launched before dawn from the Tanegashima Space Center. The Japan Aerospace Exploration Agency (JAXA) confirmed spacecraft separation roughly an hour after liftoff, prompting celebrations in mission control.
While NASA and China have successfully landed on Mars itself, no mission has yet touched down on Phobos or its smaller companion, Deimos, nor returned material from the Martian system. If successful, MMX will deliver samples to Earth in 2031. “There’s a lot of adrenaline and a lot of excitement and a lot of wow,” said NASA astrophysicist Tom Statler, a project participant. JAXA enters the endeavor with a proven track record, having previously returned samples from two asteroids.
Phobos is an irregular, potato-shaped body roughly 14 miles (22 kilometers) wide. Analyzing its composition could resolve a long-standing debate: whether the Martian moons formed from debris after a giant impact with Mars or are captured asteroids. The $578 million mission involves a 5-ton spacecraft expected to reach Mars orbit by late summer 2027.
Upon arrival, the probe will deploy Idefix, a Franco-German rover named after the dog from the Asterix comics. Roughly the size of a microwave oven, the four-wheeled rover will drop onto Phobos, bouncing to a stop in the moon’s minuscule gravity. It is designed to self-right if it lands upside down, though soft soil or crevices could immobilize it. Once its solar panels deploy, the rover loses this capability and will creep along at 1 millimeter per second. Over 100 days, Idefix will act as a “scout for safety,” mapping terrain to guide the main lander to a secure sampling site.
The stationary lander is slated to touch down in late 2028 or 2029 for a brief two-hour stay. It will drill and vacuum at least 10 grams (one-third of an ounce) of material before ascending. The spacecraft will then conduct flybys of Deimos before departing the Martian system in 2030 for a 2031 sample return capsule landing in the Australian desert.
The mission navigates a path littered with past failures. The Soviet Union and Russia failed in three dedicated Phobos attempts, and Japan’s previous Mars orbiter failed to enter orbit. Even NASA has endured losses probing the Red Planet. Yet the scientific payoff is immense. Material on Phobos likely includes ejecta blasted off Mars by ancient impacts, offering a “two-for-one” sample that could illuminate planetary formation and the history of water and potential life on Mars. “It is a once-in-a-lifetime chance. We are part of the first sample return mission from the Martian system,” said Markus Grebenstein, rover project manager at the German Space Agency (DLR).
Japan is not alone in targeting Martian samples. China plans a Mars sample return launch around 2028, also targeting a 2031 Earth return, while NASA continues to formulate a strategy to retrieve the caches collected by the Perseverance rover. The MMX budget totals approximately $578 million, with Japan contributing roughly $350 million, NASA $87 million, the French Space Agency (CNES) $68 million, DLR $56 million, and the European Space Agency $17 million.
