Japan launches first mission to bring Martian moon samples to Earth

Japan has launched the world’s first mission to collect samples from Phobos, one of Mars’ two irregular, potato-shaped moons, using the new H3 rocket ^[1]. The Martian Moons eXploration (MMX) mission, led by the Japan Aerospace Exploration Agency (Jaxa), is set to return to Earth in 2031 after a five-year journey ^[2]. Scientists hope the samples will reveal how Phobos and Deimos formed—whether as debris from a Mars impact or captured asteroids—potentially shedding light on the origins of life in the solar system.

The spacecraft, weighing about 5 tons, will carry 13 instruments, including a French-German rover named Idefix, which will land on Phobos in 2029 for a 100-day surface survey ^[2]. This data will help select a safe, smooth landing site for the main MMX module, which will then attempt two sample collection operations using both NASA’s pressurised gas method and Jaxa’s coring technique to gather at least 10g of soil ^[1].

Phobos, about 27km in diameter and orbiting Mars at just 6,000km, has only one two-thousandths of Earth’s gravity, making landing and sampling extremely challenging ^[1]. The exploration module features four-legged landing gear with shock absorption to prevent bouncing ^[2]. The rover is designed to move at a snail’s pace, self-right if overturned, and maintain traction in low gravity.

After three years of orbital study around Phobos, the return module will detach and bring the heat-protected capsule back to Earth, expected to land in Australia before being sent to Japan ^[1]. The mission also includes flybys of Deimos and data collection from gamma-ray instruments and European deep-space communications ^[2]. Jaxa’s previous Hayabusa missions successfully returned asteroid samples in 2010 and 2020.

This mission marks a major leap in planetary science, with potential implications for future human missions to Mars ^[1]. According to Jaxa officials, the analysis of Phobos soil samples may allow scientists to come to a conclusion about the moons’ origins, though this has not been confirmed. The story was first reported by The Guardian and New York Post.