Japan Launches MMX to Bring Back the First Samples From Mars' Moon Phobos

Before dawn on Tuesday in southern Japan, a rocket carried a probe toward the larger of Mars's two moons with a promise attached: bring a piece of it home. Japan's Martian Moons eXploration (MMX) mission launched on an H3 rocket from the Tanegashima Space Center, according to Phys.org.

The European Space Agency put the launch time at 04:41 Japan time on 20 October, which was 20:41 in London on 19 October. Officials declared success about an hour later, once the spacecraft separated from the upper stage as planned.

What is MMX trying to do?

MMX is meant to be the first mission to collect a sample from Phobos and return it to Earth, ESA says. The spacecraft weighs about 4.5 tonnes and carries a French-German rover called Idefix, Phys.org reports. Phobos is roughly 22 kilometres across, which makes it the larger of the two moons yet still tiny by planetary standards. MMX will also fly past the other moon, Deimos. The sample lander and the rover will work in very different ways, with the lander sampling for hours and Idefix roving for months.

Scientists still argue over how Mars got its moons, whether from captured asteroids or from debris thrown up by a giant impact. Material from the surface could help settle that.

When will it arrive and return samples?

ESA's mission timeline shows arrival at Mars in August 2027 and entry into orbit around Phobos in September 2027. According to Phys.org, the lander will touch down late in 2028 or in 2029 and spend about two hours on the surface, collecting at least 10 grams of material. The sample is due back on Earth in 2031, delivered to the Australian desert. The whole mission runs five years.