Japan to Launch First-Ever Mission to Collect Samples from Martian Moon
JAXA's MMX probe will attempt to retrieve at least 10 grams of rock from Phobos and return them to Earth by 2031.
What happened
Japan's Aerospace Exploration Agency (JAXA) is preparing to launch the MMX (Martian Moons eXploration) probe on October 20, 2026, from the Tanegashima Space Center. The spacecraft will take approximately one year to reach Mars, conduct three years of sample collection operations while orbiting the planet, and require another year for the return journey, with samples expected to arrive in 2031. The 4,480-kilogram probe, designed by Mitsubishi Electric, will land on Phobos and use a robotic arm to drill samples and a nitrogen-gas device to collect fine dust particles. A French-German rover called IDEFIX will conduct preliminary exploration for roughly 100 days before the main landing to identify safer landing sites. The mission costs approximately $345 million USD and marks Japan's first Mars probe launch in 28 years.
Context
The samples would be the first rocks from a Martian moon ever brought to Earth and could resolve competing scientific hypotheses about how Mars' moons formed: whether they condensed from material ejected during a massive collision with Mars or were asteroids captured by Mars' gravity. The moons' dark color and water-rich composition resemble asteroids, but their nearly circular orbits favor the giant impact hypothesis; comparison with Martian surface samples could settle the debate. Beyond scientific objectives, the mission will test new technologies for future sampling missions and round-trip travel to Mars. The extreme technical challenges—including landing on a moon with only 11-kilometer radius and operating autonomously with up to 20-minute communication delays—make this an engineering test case for deep space operations.