Japan launches historic Mars moon sample return mission

Japan successfully launched its Martian Moons eXploration probe aboard an H3 rocket from Tanegashima Space Center on October 20, 2026, marking a landmark international mission to Mars's moon Phobos. Developed in collaboration with NASA and European agencies, the probe will reach the Martian system in 2027, deploy the French-German rover IDEFIX, and collect at least 10 grams of surface material. Scheduled to return to Earth in 2031, these historic samples aim to settle debates over how Mars's moons formed and pave the way for future crewed exploration.

Launch and travel timeline

• ▪The five-tonne Martian Moons eXploration spacecraft is scheduled to arrive near Mars around August 2027 to spend three years conducting scientific observations in the Red Planet's vicinity
• ▪The Martian Moons eXploration probe successfully separated from the H3 rocket over an hour after liftoff on October 20, 2026, to begin its journey toward the Martian system
• ▪The Japan Aerospace Exploration Agency successfully launched the uncrewed Martian Moons eXploration probe aboard an H3 rocket from Tanegashima Space Center at 4:41 a.m. local time on October 20, 2026

Sample collection and Earth return

• ▪The return module of the Martian Moons eXploration spacecraft is scheduled to deliver a sample capsule to Earth in 2031, landing by parachute in the Australian outback
• ▪The Martian Moons eXploration spacecraft aims to collect at least 10 grams of dust and rock from the surface of Phobos during a two-and-a-half-hour landing operation
• ▪The Martian Moons eXploration spacecraft will use a C-sampler to drill up to 0.8 inches beneath Phobos's surface and a P-sampler using nitrogen gas to collect dust and rocks

Scientific objectives on planetary origin

• ▪Scientists hope analyzing samples from Phobos will resolve whether the moon is a captured asteroid or formed from debris generated by a giant collision involving Mars
• ▪Determining the origin of Mars's moons will clarify how terrestrial planets formed and how habitable environments arose in the early Solar System, according to the Japan Aerospace Exploration Agency

Preparing for future crewed Mars exploration

• ▪NASA Science Mission Directorate administrator Nicky Fox stated that samples from the Martian Moons eXploration mission will provide critical scientific insights as NASA prepares for human Mars missions
• ▪The Japan Aerospace Exploration Agency aims to evaluate Phobos as a potential natural space station to establish round-trip capabilities essential for future crewed Mars exploration

International contributions to the mission

• ▪The Martian Moons eXploration mission is an international collaboration involving the Japan Aerospace Exploration Agency, NASA, the European Space Agency, and French and German space agencies
• ▪The European Space Agency provided the deep space communication equipment for the Martian Moons eXploration spacecraft

Other Mars sample return efforts

• ▪The administration of Donald Trump effectively cancelled a planned NASA and European Space Agency Mars sample-return mission following a congressional vote in January 2026
• ▪China plans to launch its Tianwen-3 sample return mission to Mars around 2028 to return Martian soil samples to Earth as early as 2031