Japan launches first round-trip mission to a Mars moon

Mars has two moons, and nobody has ever touched either one. On Monday, Japan's space agency JAXA launched a spacecraft called MMX to fix that. It lifted off on an H3 rocket from Tanegashima, heading for the larger moon, Phobos. If it works, MMX will land on Phobos and scoop up rock and soil. Then it will fly that sample all the way back to Earth. No mission has ever done that at a Martian moon.

Phobos is tiny, so its gravity is almost nothing. Landing there isn't like landing on the Moon or Mars. It's closer to docking with a slow-spinning rock than touching solid ground. Scientists still don't agree on how Phobos formed. One theory says Mars' gravity captured a passing asteroid. Another says it's debris blasted off Mars by an ancient impact. A real sample, not just photos, is the only way to settle that. NASA, France's CNES, and Germany's DLR are all flying instruments on this mission. That makes it one of the most international Mars missions in years.

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Will MMX actually manage to land? Touching down on a body with almost no gravity is brutally hard. A slightly wrong approach could send the spacecraft bouncing back into space. MMX won't even reach Mars until next August. Today's launch is just the first of several risky steps ahead. The sample isn't due back on Earth until 2031.