Japan launches $578 million MMX mission to retrieve Martian moon samples

The Japan Aerospace Exploration Agency launched a spacecraft on Tuesday to land a rover on Phobos and return the first-ever samples from the Martian system to Earth.

The spacecraft lifted off before dawn from Tanegashima Island, marking the start of a five-year mission backed by five international space agencies. According to Euronews and France 24, flight controllers confirmed the 5-tonne craft successfully separated from its rocket an hour after launch. The $578 million project, known as Martian Moon Exploration (MMX), aims to bring soil and rock samples back to Earth in 2031.

While the spacecraft is expected to reach the Mars vicinity by late next summer, BBC News specifies an arrival date in August 2027. It will sync with the orbit of Phobos, a potato-shaped moon roughly 22 kilometers across, to deploy a microwave-sized rover named Idefix. The French-German rover will bounce across the surface in extremely low gravity, moving at just 1 millimeter per second to scout for a safe site for the main lander to touch down.

The mission's primary objective is to collect roughly 10 grams of material. Dr. Chrysa Avdellidou told the BBC that even individual grains are sufficient for scientific study. The landing for sample collection is planned for late 2028 or shortly thereafter, with the collected material eventually being sealed in a capsule intended for a landing in the Woomera desert of South Australia.

Scientists hope the mission will reveal whether Phobos and Deimos were formed from debris after a massive collision or if they are captured asteroids. Prof. Sara Russell noted that landing a rover on such a small moon is difficult because the strong gravity of nearby Mars competes with the moon's own weak pull. If successful, Japan would build on its experience of completing two previous asteroid sample returns.

Background

Phobos and Deimos are the only two moons in the inner Solar System besides Earth's moon. No previous mission from any nation has successfully landed on these Martian moons or returned samples from them to Earth.