A bold mission by the Japan Aerospace Exploration Agency (JAXA) to Mars’ two moons, including a lander component for one of them, is all set to enter the development phase after the plan was submitted to the Japanese government’s science ministry this week.

Dubbed the ‘Martian Moons Exploration’ (MMX) mission, the goal is to launch the probe in 2024, using the new H-3 rocket being developed by Mitsubishi Heavy Industries, which is expected to launch for the first time sometime later in 2020. The probe will survey and observe both Phobos and Deimos, the two moons that orbit the red planet, which are both smaller and more irregularly shaped than Earth’s Moon.

The MMX lander will park on Phobos, while the probe studies the two space-based bodies from a distance. This is the first ever mission that seeks to land a spacecraft on one of the moons of Mars, and it’ll include a rover that is being developed by JAXA in partnership with teams at German space agency DLR, and French space agency CNES.

The mission will include an ambitious plan to actually collect a sample of the surface of Phobos and return it to Earth for study, too – which will mean a round-trip for the MMX spacecraft that should see it make its terrestrial return by 2029.

NASA is also planning a Mars sample return mission, which would aim to bring back a sample from the red planet itself using the Mars 2020 six-wheels rover that its planning to launch later this year.

Both of these missions could be crucial stepping stones for eventual human exploration and colonization of Mars. It’s possible that Phobos could act as an eventual staging ground for Mars missions, since its lower gravity makes it an easier body from which to depart for eventual astronauts. And Mars is obviously the ultimate goal for NASA’s Artemis program, which seeks to first establish a more permanent human scientific presence on the Moon before heading to the red planet.