Japan launches MMX mission to collect samples from Phobos
Japan’s MMX spacecraft has begun a five-year mission to collect samples from Mars’s moon Phobos and return them to Earth.
Japan has launched the Martian Moons eXploration mission, or MMX, on a five-year journey to collect samples from Phobos and return them to Earth. The mission lifted off from Tanegashima Space Center aboard an H3 rocket, beginning one of the most ambitious planetary-science projects in Japan’s history.12
A five-year mission to Phobos
The MMX spacecraft is travelling to Phobos, the larger of Mars’s two moons. JAXA’s mission plan calls for the spacecraft to enter a quasi-satellite orbit around Phobos, study the moon in detail and perform two soft landings to collect more than 10 grams of surface material.1
The returned samples could help scientists work out whether Phobos formed alongside Mars or is a captured asteroid. JAXA says the mission will examine the moon’s topography, internal structure, composition and gravity, while also observing Deimos during the later stages of the expedition.1
Ars Technica reports that the mission launched with a mass of almost 9,900 pounds and separated from the H3 upper stage roughly 71 minutes after liftoff. The spacecraft then established contact with ground controllers and deployed its solar panels, with mission officials describing it as being in a very stable condition shortly after separation.2
The launch is also a major test for the H3 rocket, Japan’s flagship launch vehicle. MMX flew on a more powerful H3 configuration with four solid rocket boosters and an extended payload shroud. That extra lift was needed for a spacecraft designed not only to reach the Martian system, but also to land on a moon, collect material and make the return trip.2
What happens next
JAXA’s published mission schedule sets out a long road ahead. MMX is expected to reach the Martian sphere in 2027, conduct observations and sample collection between 2027 and 2030, depart the system in 2030 and return its capsule to Earth in 2031.1 Those dates are targets rather than guarantees: deep-space missions have to manage communication delays, navigation risks and the demanding mechanics of landing on a small, low-gravity world.
If the sample return succeeds, MMX will give researchers fresh material from a part of the Solar System that has never previously been sampled. It could also provide a useful comparison with Japan’s Hayabusa and Hayabusa2 asteroid-return missions, while testing technologies needed for future exploration of Mars and its moons.
Our opinion
MMX matters because it is more than a spectacular launch. Phobos may preserve clues about the early Mars system, but reaching it, landing safely and returning a sample is a chain of difficult engineering problems. The mission’s five-year timetable makes this a story that will unfold in stages, beginning with the first successful departure and ending—if everything goes to plan—with material from another world in laboratories on Earth.