Japan Launches MMX Mission to Return Samples From Mars’s Moon Phobos

Japan has successfully launched its Martian Moons eXploration spacecraft on a mission to collect the first samples returned from a Martian moon, The Guardian and Good News Network reported.

The Guardian reported that an H3 rocket carried MMX into space before dawn from Tanegashima island, citing the Japan Aerospace Exploration Agency, JAXA. Good News Network dated the launch to October 19.

The mission centres on Phobos, the larger of Mars’s two moons, while also investigating its smaller companion, Deimos. NASA, The Conversation, New Scientist and The Guardian described the mission’s objective as resolving how the moons formed.

Two competing explanations are that Mars captured passing asteroids or that material thrown into orbit by an impact gradually formed the moons, according to NASA and The Conversation. Analysing Phobos’s composition could help distinguish between these possibilities.

NASA said the investigation could also illuminate the early period when Earth and other inner planets acquired water and organic compounds. The Guardian reported that scientists hope the mission will contribute to understanding the solar system’s origins and life on Earth.

The Conversation described MMX as a five-year mission led by JAXA with participation from the United States, France, Germany and the European Space Agency. Both NASA and The Conversation placed its arrival at Mars in August 2027 and its sample return in 2031.

NASA’s contributions include an instrument called MEGANE, which measures gamma rays and neutrons to determine Phobos’s elemental composition. NASA also provides a pneumatic sampler, Deep Space Network communications and navigation support, and funding for participating US scientists.

According to NASA, approximately 15% of the returned material will be curated at Johnson Space Center’s Astromaterials Lab in Houston for research over subsequent decades.

The Conversation added that MMX carries 13 science instruments. Cameras will map Phobos, a laser altimeter will measure its contours, and an infrared spectrograph will examine minerals. Measurements will help controllers choose a landing site.

The spacecraft also carries Idefix, a small rover developed jointly by JAXA, France’s CNES and the German Aerospace Center, The Conversation reported. Its deployment is planned for early 2029, with an expected operating period of about 100 days.

The Conversation described a descent from between 40 and 100 metres above Phobos, after which the rover would right itself and examine the surface. Sampling is technically difficult because the moon’s gravity is about 0.1% of Earth’s, the outlet reported.

The accounts give different sampling schedules. NASA said collection would occur no earlier than December 2028, while The Conversation described a spacecraft landing in 2030 lasting around 2.5 hours.

They also characterised the sampling systems differently. NASA described its nitrogen-powered P-Sampler as complementing JAXA’s core-extracting C-Sampler. The Conversation described the P-Sampler as a backup option and said the C-Sampler could reach up to two centimetres below the surface.

BBC News described the mission’s target as bringing back 10 grams of moon dust. The Conversation specified at least 10 grams and reported that the return capsule would descend by parachute in Australia before transport to Japan.

The Conversation also identified a possible additional scientific opportunity: Phobos may contain material ejected from Mars by asteroid impacts. Any such material in the returned samples could allow laboratory investigation of the planet alongside its moon.

Sources

• NASA: NASA to Help Unlock Mysteries of Mars’ Moons in Upcoming Mission
• The Conversation: Japan’s MMX mission aims to swipe soil samples from Mars’ moon Phobos
• New Scientist: Japan is launching a mission to Mars’s largest moon Phobos
• The Guardian: Japan to launch world-first mission to collect samples from Martian moon
• BBC News: Mission blasts off for Mars to grab a piece of its moon
• The Guardian: ‘Once-in-a-lifetime chance’: Japan launches historic mission to collect rocks from Mars’s moon Phobos
• Good News Network: Japan Successfully Launches Mission to Bring Home the First-Ever Martian Moon Samples