Science · 2026-10-23 · Afternoon briefing

Japan launches mission to uncover origin of Martian moons

Japan’s Martian Moons Exploration (MMX) spacecraft launched on October 19th, beginning a mission to solve a mystery dating back to 1877: the origin of the Martian moons, Phobos and Deimos. The probe, operated by the Japan Aerospace Exploration Agency, will land on Phobos, collect a 10-gram sample of surface material, and return it to Earth for analysis in 2031.

After a year-long journey, MMX will deploy a 24kg rover named Idefix, a joint project by the French and German space agencies. If the landing is successful, Phobos, at just 26km in length, will become the smallest celestial body ever explored by a wheeled vehicle. The main spacecraft will then perform its own landing to retrieve the sample before observing Deimos during its return flight.

Analysis of the sample is expected to determine whether the moons are captured asteroids or debris from a colossal impact on Mars. The mission carries high stakes; all previous dedicated attempts to reach Phobos, by the Soviet Union and a later Russian-Chinese partnership, failed before arriving at the moon.

Summary written by Cup of News with AI from the sources below. Check the originals for the full story.

Read the sources

• Japan launches spacecraft to explore Mars’s mysterious moons
• Japan Successfully Launches Mission to Bring Home the First-Ever Martian Moon Samples
• How did Mars get its moons? Japan’s MMX mission is about to find out
• Japan launches ambitious mission to grab a chunk of a Martian moon
• Scientists Don’t Know How Mars Acquired Its Two Moons. Japan Just Launched a Historic Space Mission That Will Fetch Samples to Find Out

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