JAXA, Japan's space agency, is moving ahead with a first-of-a-kind mission to explore the two moons of the Mars system, Phobos and Deimos. All going to plan, the Martian Moon Exploration (MMX) mission will return to Earth with the first ever samples of a Martian moon by the end of the decade, which scientists hope may offer a few clues about Mars' formation and its watery past.

The Japanese government officially approved the development phase of the MMX mission this week, which means the scientists working on it will now turn their attention to building the hardware and software needed for a pioneering return journey to the Red Planet. The spacecraft will begin with a one-year orbit of Mars, and then turn its attention to its pair of moons, which are of considerable interest to the science community.

This is because their formation is the source of much debate. Phobos and its smaller sibling Deimos have the appearance of asteroids, and may have been collected from the asteroid belt and swung inwards by Mars' gravity. An alternative theory is that they formed as a result of some kind of large impact with Mars. Either way, scientists expect the moons to serve as valuable time capsules full of ancient materials ejected by Mars over billions of years, offering insights into the formation of bodies and water transport within the Martian system.

Overview of the planned MMX mission

The Japan Aerospace Exploration Agency's MMX spacecraft will use 11 onboard instruments to study both Phobos and Deimos from orbit, but will then close in on Phobos for landing and sample collection, similar to Japan's Hayabusa2 spacecraft that is currently returning to Earth with a sample collected from the asteroid Ryugu.

Where Hayabusa2 collected a tiny sample of 0.1 g from the surface, the MMX spacecraft has lofty aims of collecting a 10-g (0.35-oz) sample. It will do this using a corer instrument capable of burrowing 2 cm (0.8 in) into the surface, before leaving and carrying the sample back to Earth. If it is successful, it will mark the first ever round-trip to the Martian system.

Another aspect of the mission is the consideration of a future human base in the area. By visiting Mars and its moons, the MMX spacecraft will demonstrate the technology needed to enter and escape Mars' gravitational well, land and traverse the surface of a small, low-gravity body, and deploy scientific instruments. In addition, the mission will assess the radiation it encounters, which remains a key consideration for future Mars missions.

“Humans can realistically explore the surfaces of only a few objects and Phobos and Deimos are on that list,” notes NASA Chief Scientist, Jim Green. “Their position orbiting about Mars may make them a prime target for humans to visit first before reaching the surface of the Red Planet, but that will only be possible after the results of the MMX mission have been completed.”

The MMX mission is slated for launch in 2024 and is expected to arrive at Mars in 2025. With departure scheduled for 2028, all going to plan the spacecraft will return to Earth with its sample in tow in 2029.

Source: Japan Aerospace Exploration Agency