Lift-off: the Martian Moons eXploration mission will aim to collect 10g of material from Phobos (courtesy: JAXA)

Japan has launched a sample-return mission to the Martian moon Phobos. The Martian Moons eXploration (MMX) mission took off yesterday at 04:41 local time from the Tanegashima Space Centre in Japan aboard a H3 rocket. It will now spend the next year travelling to Mars and to return samples from Phobos by 2031.

Of all the moons in the solar system, Phobos is among the most enigmatic in origin. With its irregular shape, cratered surfaces and a diameter of around 25 km, it is commonly believed to be an asteroid pulled in by Mars’ gravitational field.

However, Phobos also follows a highly circular orbital path, which lies almost perfectly in Mars’ equatorial plane.…