Japan's Mars moon mission aims to bring samples home despite Phobos’ treacherous, low gravity terrain

Japan is about to embark on a groundbreaking mission, the first of its kind, to retrieve samples from Phobos, one of Mars' two moons. The mission, expected to span five years, aims to unravel the origins of these enigmatic moons and potentially provide insights into the emergence of life within the solar system. The Japan Aerospace Exploration Agency (JAXA) will launch the spacecraft on its state-of-the-art H-3 rocket on Tuesday.

This ambitious project, spearheaded by JAXA's Yasuhiro Kawakatsu, will offer a wealth of data for scientists to contemplate establishing a Martian moon base for future manned missions to the red planet. Kawakatsu emphasizes that despite their significance, Martian moons have never undergone comprehensive exploration, describing them as the "most important unclimbed mountains" in our solar system.

Scientists have long speculated about the formation and composition of Phobos and its smaller companion, Deimos, which derive their names from Greek mythological figures representing fear and terror. Russian attempts to land on Phobos, including a failed mission in 2011, have only added to the intrigue surrounding these celestial bodies.

Merits of targeting Phobos as the sampling site stem from its proximity to Mars, allowing for a higher likelihood of obtaining crucial information about the planet itself. Approximately 0.1% of the collected material is anticipated to consist of Martian soil. Phobos, measuring between 20 to 30 kilometers in diameter, orbits Mars at a distance of 6,000 kilometers, completing a lap around the planet every three days.

The MMX spacecraft, weighing around 5 tons, will comprise three modules: propulsion, exploration, and return. Upon reaching the Mars region a year post-launch, MMX will spend three years studying Phobos before returning to Earth in 2031. The spacecraft carries 13 instruments, including a rover jointly developed by France and Germany, a NASA sampling device, a gamma-ray measuring instrument provided by NASA, and a deep space communication device from the European Space Agency.

A Japanese radiation monitor will also collect essential data for potential future manned Mars exploration.

The joint French-German rover, named Idefix, will land on Phobos for a 100-day mission starting around 2029, exploring the moon's surface to facilitate subsequent Japanese soil-sampling attempts. MMX's mission will collect at least 10 grams of soil from two sampling efforts employing U.S. and Japanese techniques. NASA's sampling device utilizes pressurized gas to lift surface dust into a container, while JAXA's coring method will retrieve samples from a depth of about 2 centimeters.

The decision to collect samples from multiple locations aims to maximize the chances of identifying any potential traces of past microbial life on Mars. Once collected, the samples will be stored in a heat-protected capsule designed to survive reentry into Earth's atmosphere, which is expected to land in Australia before being transported back to Japan. Japan's past lunar sample missions, Hayabusa and Hayabusa2, returned asteroid samples in 2010 and 2020, respectively.