In 2010, Hayabusa became the first spacecraft to land on an asteroid, collect samples, and return them to Earth. Now JAXA, the Japanese space agency, is hoping to do it all over again–this time on one of Mars’ potato-shaped moons.

JAXA announced on Tuesday that it wants to land a probe on Deimos and/or Phobos to scrape up some dirt and bring it back to Earth-bound scientists. The samples could tell us about the composition and history of these moons.

The mission does not have funding secured yet, and details about the spacecraft, its target, and the timeline are still hazy, but JAXA thinks the mission could launch by 2022. If it gets off the ground, the spacecraft would be the first to land on a Martian moon. Russia attempted a sample-return from Phobos with its 2011 Phobos-Grunt mission, but the probe crashed back to Earth before it could leave orbit.

The new mission may potentially influence NASA’s plans to put humans on Mars in the 2030s. Support seems to be growing for the idea of using Phobos or Deimos as a stepping stone to Mars. The moons would be easier and cheaper to land on than the planet itself. One plan, proposed by NASA Jet Propulsion Lab scientists, involves sending astronauts to a base camp on Phobos, and later shuttling them down to Mars. The Planetary Society has drawn up a similar plan.

But before we try to put people on Mars’ moons, it’s a good idea to send some unmanned spacecraft to scope the place out. The lessons we learn from the proposed JAXA mission could help to ensure that astronauts land safely and know what to expect when they get there.