Japan’s probe targets mystery of Mars’s moons

A Japanese spacecraft has begun its journey to Mars to collect samples from the moon Phobos and help explain how the planet’s two moons formed. The probe separated successfully from its H3 launch vehicle on Tuesday, ERR reported.

The Japan Aerospace Exploration Agency’s MMX mission aims to study the surface of potato-shaped Phobos and return at least 10 grams of material to Earth. Scientists will be able to examine the samples in laboratories, where they can analyse their composition more precisely than instruments aboard the spacecraft allow.

Astronomer Tõnis Eenmäe said the mission could both demonstrate JAXA’s capabilities and help address questions about how planets and their moons form. Previous missions to study Mars’s moons have been planned, he said, but MMX could become the first successful mission to bring material back from one of them.

The origins of Phobos and Deimos remain uncertain. One hypothesis is that they formed alongside Mars from leftover material. Another is that an impact with a larger celestial body sent material into orbit around the planet. A third theory holds that the moons are asteroids captured by Mars’s gravity.

Samples from Phobos could show whether its material is more similar to Martian rocks or to asteroids. That evidence could help scientists assess which formation theory is most likely. If the moons are captured asteroids, their composition could also provide information about objects from more distant parts of the solar system.