The longstanding mystery of Mars’ moons – and the mission that could solve it Premium

the Japan Aerospace Exploration Agency will launch a mission, named “Martian Moon eXploration”, to Phobos and Deimos in September 2024. The mission will be carried by a newly designed rocket, the H-3, which is still under development.

The two small moons of Mars, Phobos (about 22km in diameter) and Deimos (about 13km in diameter), have been puzzling scientists for decades, with their origin remaining a matter of debate. Some have proposed that they may be made up of residual debris produced from a planet or large asteroid smashing into the surface of Mars (#TeamImpact).

An opposing hypothesis (#TeamCapture), however, suggests the moons are asteroids that were captured by Mars’s gravitational pull and were trapped in orbit.

To solve the mystery, we’ll need material from the moons’ surfaces for analytical analyses on Earth. Luckily, the Japan Aerospace Exploration Agency (Jaxa) will launch a mission, named “Martian Moon eXploration” (MMX), to Phobos and Deimos in September 2024. The mission will be carried by a newly designed rocket, the H-3, which is still under development.

The spacecraft is expected to reach Martian orbit in 2025, after which it will orbit Phobos and finally collect material from its surface before returning to Earth by 2029.

This will make it the next in a series of recent missions bringing material from space back to Earth, following on from Jaxa’s successful mission to asteroid Ryugu (Hayabusa2), as well as Nasa’s Osiris-Rex mission to asteroid Bennu and the Chinese Space Agency’s Chang’e 5 mission to the Moon.

If an impact origin did indeed occur, we would expect to find similar material on Phobos to that which is found on Mars. While we do not have any material returned directly from Mars (yet), we are lucky enough to have rock that has been ejected off its surface which eventually found its way to Earth.

These meteorites may therefore be similar to the material returned from Phobos, providing a fantastic comparison.