Japan Is Going to a Moon of Mars — and Bringing a Piece of It Home

Look up at Mars on a clear night and you’ll see a small red dot. Circling it, far too small to see, are two tiny moons. One of them, Phobos, is about to get a visitor from Japan.

On October 20, 2026, Japan’s space agency JAXA launched MMX (Martian Moons eXploration) on an H3 rocket from the Tanegashima Space Center in southern Japan. The probe is now on its way to Mars — and if all goes to plan, it will scoop up material from Phobos and bring it back to Earth.

The mission in four steps

1. Launch (done): The H3 rocket lifted off on schedule, and about 71 minutes later released MMX onto a path toward Mars. It was the first time an H3 rocket sent a probe toward Mars.
2. Travel: The journey to orbit around Mars takes roughly a year.
3. Collect: MMX will study Phobos and collect samples, like sand and small rocks, from its surface.
4. Return: The samples are scheduled to arrive back on Earth in July 2031.

The day after launch, JAXA reported that the probe’s basic functions — generating power, controlling its orientation and communicating with the ground — were all working normally.

Why a moon of Mars?

If MMX succeeds, it will be the first mission ever to bring samples back from the Mars system. Scientists hope Phobos can help answer a big question: where did Mars’ moons come from? Were they asteroids captured by Mars’ gravity, or pieces blasted off Mars itself in a giant impact? If it’s the second, Phobos might even hold bits of ancient Mars.

Japan has already brought home pieces of two asteroids. Now it’s aiming for a moon of Mars.

A country that loves sample returns

This mission builds on a famous Japanese track record. The Hayabusa probe brought back particles from asteroid Itokawa in 2010 after a dramatic, problem-filled journey. Hayabusa2 returned samples from asteroid Ryugu in 2020. Both became national stories, followed closely by the public.

The H3 rocket has had its own drama. After a failure in December 2025, this launch marked its third straight success — a relief for Japan’s space program.

Space Japanese you’ll hear in the news

• 探査機 (tansaki) — space probe. 探査 = exploration, 機 = machine.
• 打ち上げ (uchiage) — launch. Fun fact: the same word means an after-party when a project or show ends. Context makes it clear.
• 衛星 (eisei) — satellite. It’s used for both artificial satellites and natural moons, so フォボスは火星の衛星 = “Phobos is a moon of Mars.”
• 試料 (shiryō) — sample (in science). Not to be confused with 資料 (shiryō), documents — same sound, different kanji.
• 帰還 (kikan) — return home (formal). You’ll see 地球帰還, “return to Earth.”

Watch for the next headlines

Expect Japanese news to report milestones as MMX travels: course corrections, arrival at Mars, and the sampling. When you see 成功 (seikō, success) in a headline, you’ll know it’s good news.

For more from this week in Japan, read about the country’s new disaster agency, or learn why Japanese people say やばい when something is out of this world.