Japan launched a historic mission to bring back samples from Mars’ Moon Phobos. If successful, Japan will become the first country to get samples from the Martian moon.
Mars has two moons — Phobos and Deimos. Phobos is a lumpy, potato-shaped rock just 14 miles (22 kilometers) or so across. Examining pieces of it can explain how Mars’ moons — and possibly moons elsewhere — came to be.
The Japan Aerospace Exploration Agency (JAXA) launched the Martian Moons eXploration (MMX) spacecraft aboard H3 Launch Vehicle flight No.10 at 04:41:03 JST on October 20, 2026 from the Tanegashima Space Center.
The H3 Launch Vehicle flew as planned, and approximately 71 minutes and 13 seconds after liftoff, the separation of the MMX spacecraft was confirmed. The MMX spacecraft was then injected into the predetermined orbit, “beginning its journey toward the Martian system”.
“I’d dreamt of this day, so I’m incredibly happy,” JAXA scientist Mari Aida was quoted by AFP as saying. “Right now I feel really relieved.”
Five of the world’s space agencies joined forces for the five-year mission that will attempt to land a robotic prospector plus a rover on Phobos, the larger and closer of Mars’ two pint-sized moons.
Dubbed MMX for Martian Moons Exploration, the mission costs $578 million and features a hefty 5-ton spacecraft, the Associated Press reported.
The Japan Aerospace Exploration Agency, or JAXA, developed it at a cost of 55.3 billion yen, or roughly 350 million dollars.
NASA has invested approximately $87 million through the end of the mission, which includes funding for United States scientists and astromaterials experts on the MMX team, according to Space.com.
The spacecraft is due to arrive near Mars around August next year, where it will orbit one of its moons, Phobos.
A French-German rover dubbed IDEFIX — the French name for the comic hero Asterix’s dog — will be the first vehicle to travel across Phobos, conducting surface observations aimed at ensuring a safe landing.
Once MMX arrives on Phobos, it will collect at least 10 grams (0.35 ounces) of material from the surface during its planned three years in the Red Planet’s vicinity.
The lander will spend just two hours on Phobos before launching back into space.
The mission will also observe the planet’s other moon, Deimos, although it will not land on it. It will study Deimos during a series of flybys before leaving the Martian neighborhood in 2030 and hustling back to Earth for a 2031 sample delivery in the Australian desert.
If successful, bits of dust, soil and rocks from Phobos will arrive on Earth in 2031.
“There’s a lot of adrenaline and a lot of excitement and a lot of wow,” said NASA astrophysicist Tom Statler, who’s involved with the project.
Scientists hope the Japanese Martian mission will help lay the groundwork for eventual human exploration.
“The samples from MMX will bring forth paradigm-shifting science on the Mars system for generations to come, especially as NASA prepares to send the first humans to Mars,” Nicky Fox, administrator of NASA’s Science Mission Directorate, said in a message of encouragement broadcast on the JAXA live stream.
Meanwhile, JAXA hopes the mission will reveal how Mars and its two moons formed, a key piece of knowledge in working out how the Solar System was born.
One theory for the origin of the moons — the “giant impact” hypothesis — is that they formed after a celestial body collided with Mars.
The “capture” hypothesis, meanwhile, postulates that the moons are asteroids pulled in by Mars’s gravity.
Determining which theory is correct will help reveal “how a habitable environment for life might have arisen on the terrestrial planets”, JAXA said, referring to the four rocky worlds closest to the Sun — Mercury, Venus, Earth and Mars.
JAXA said the mission will also explore the possibility of using Phobos — Martian Moon — as a “natural space station” by establishing the requirements for a round trip — something “essential for crewed Mars exploration”.
The US and Chinese space agencies have also been vying to be the first to return rock samples from the surface of Mars back to Earth.
While NASA has successfully landed nine spacecraft on Mars over the past 50 years and China scored a 2021 touchdown, no one has ever ventured onto Phobos or its sidekick Deimos. And no one has managed to fetch samples from Mars, let alone its moons.
NASA’s Perseverance rover, which has been roaming across Mars since 2021, has already collected samples. The return mission, however, was effectively cancelled by the administration of President Donald Trump following a vote by Congress in January.
MMX is not the first Phobos sample-return project to take flight, by the way. That distinction goes to Russia’s Phobos-Grunt (“Phobos-Soil”) mission, which launched in November 2011 but failed to get out of Earth orbit due to a rocket glitch. The 14.5-ton spacecraft eventually crashed back to Earth over the Pacific Ocean in January 2012.
China’s Tianwen-3 spacecraft is scheduled for launch around 2028 and hopes to return Mars samples to Earth as early as 2031 — potentially before the Japanese mission’s return.
