Japan launches first-of-its-kind mission to bring back rocks from Mars’s moon Phobos

Japan has launched a landmark mission to collect rock and soil samples from Phobos, one of Mars's two moons, in a bid to unravel the origins of the Martian moons and gain new insights into the Red Planet's evolution.

According to The Guardian, the Japan Aerospace Exploration Agency's (JAXA) Martian Moons Exploration (MMX) mission aims to collect samples from Phobos and return them to Earth by 2031, potentially providing scientists with material to investigate the formation of the moons and the early history of Mars.

The Idefix rover, jointly developed by the French space agency CNES and the German Aerospace Center (DLR), measures approximately 41.5 cm in length, 37.6 cm in width and 23.1 cm in height, and weighs around 25 kg. It is scheduled to land on Phobos around late 2028 or early 2029 and operate on the moon's surface for approximately 100 days.

The spacecraft is designed to study Phobos and Deimos, the two moons of Mars, before attempting a landing on Phobos to collect surface material. JAXA aims to bring back at least 10 grams of samples, which will be analysed in laboratories on Earth to help scientists investigate the moons' composition and formation.

The mission is expected to reach the Martian system in 2027, where it will conduct detailed observations of the moons. The sample-return capsule is scheduled to reach Earth in 2031, marking a major milestone in Japan's planetary exploration programme.

Operating on Phobos presents technical challenges because its gravity is extremely weak, making it difficult for a lander or rover to maintain stable contact with the surface. The rover is designed to demonstrate technologies for exploring small celestial bodies and improve understanding of the conditions the main spacecraft will encounter during sample collection.

Beyond its scientific objectives, the MMX mission is expected to advance technologies for future planetary exploration, including landing on low-gravity bodies, collecting extraterrestrial material and returning samples safely to Earth. The findings could deepen scientists' understanding of the evolution of Mars and its moons while providing valuable insights for future missions to the Martian system.

The mission's central scientific objective is to determine how Phobos and Deimos formed. Scientists remain divided over whether the moons are asteroids captured by Mars's gravity or formed from debris ejected when a large object struck the planet. Samples collected from Phobos could help resolve this debate and offer clues about Mars's early history.

Researchers will also examine whether the material contains traces of Martian rocks thrown into space by ancient impacts, potentially providing additional information about the planet's composition and geological evolution.