A Japanese spacecraft launched toward Mars on Tuesday, embarking on an unprecedented mission to explore the planet’s enigmatic moons and return samples to Earth.
Five international space agencies have collaborated on the five-year endeavor, aiming to deploy a robotic prospector and rover on Phobos, the larger and closer of Mars’ two small moons.
The Japan Aerospace Exploration Agency (JAXA), leading the initiative, launched the spacecraft before dawn from the main spaceport on Tanegashima Island. Mission success was confirmed an hour later when the spacecraft successfully separated from the rocket’s upper stage.
Flight controllers erupted in applause, exchanging handshakes and embraces in celebration.
A Historical First for Mars and Its Moons
While NASA has landed nine spacecraft on Mars over the past five decades and China achieved a landing in 2021, no mission has yet ventured onto Phobos or its companion Deimos. No samples have ever been returned from Mars or its moons. Should the mission succeed, dust, soil, and rock from Phobos are expected to reach Earth in 2031.
“There’s a lot of adrenaline, excitement, and wow,” said NASA astrophysicist Tom Statler, who is involved in the project.
Japan brings significant experience to the mission, having successfully completed two asteroid sample return missions previously.
Phobos is a irregularly shaped, potato-like rock approximately 22 kilometers in diameter. Investigating it may provide crucial insights into the formation of Mars’ moons and potentially those orbiting other planets.
The $578 million mission, designated MMX for Martian Moon Exploration, centers around a 5-tonne spacecraft anticipated to arrive at Mars by late next summer. Upon arrival, it will synchronize with Phobos’ orbit before deploying Idefix, a Franco-German rover named after the fictional white terrier from the Asterix comics.
Idefix, no larger than a microwave oven, will conduct a autonomous descent onto Phobos, bouncing for several minutes before settling on the moon’s extremely low-gravity surface.
What Happens After Idefix the Rover Lands?
The four-wheeled rover is engineered to self-right if it lands inverted. However, mission risks remain—if it sinks into loose soil or becomes trapped between rocks, as noted by the French Space Agency’s Julien Baroukh. Once the rover’s solar panels unfold, it loses the ability to reorient itself, necessitating a cautious speed of just 1 millimeter per second (0.04 inches per second).
“Idefix will function as a ‘scout for safety,'” explained Baroukh, as the rover surveys Phobos for 100 days. Japanese flight controllers are particularly focused on identifying safe landing zones—avoiding powdery terrain and hazardous topography—for the mothership’s descent to collect samples in late 2028 or 2029.
The stationary lander will spend only two hours on Phobos’ surface, drilling and collecting at least 10 grams (one-third of an ounce) of material before ascending back into space. Following this, the spacecraft will conduct flybys of Deimos, depart the Martian system in 2030, and return to Earth with its precious cargo, landing in the Australian desert in 2031.
The mission presents considerable challenges, given the unforgiving nature of space exploration. The moons’ names themselves are ominous: Phobos and Deimos mean “fear” and “dread” respectively in Greek mythology—they are the twin sons of Ares, the Greek god of war (known as Mars in Roman mythology).
Scientists Seek Answers About the Origins of Mars’ Moons
Russia’s previous attempts to explore Phobos all ended in failure, along with numerous other Mars missions. Japan too experienced setbacks in earlier Mars endeavors. Even NASA has faced setbacks in answering one of the most compelling questions: Did life ever exist on Mars?
By analyzing samples from Phobos, scientists hope to determine whether the moons formed following an ancient collision between Mars and a massive asteroid, or if they are captured asteroids drawn in by Mars’ gravitational pull.
Whichever origin theory proves correct, researchers anticipate discovering traces of Mars itself on Phobos. These samples represent an invaluable dual opportunity to unravel mysteries surrounding planetary formation—and possibly the conditions that led to life. According to Lindsay Hays, NASA’s acting planetary science director, the findings will significantly influence future Mars missions, including those carrying human astronauts.
“This is a once-in-a-lifetime opportunity. We are part of humanity’s first sample return mission from the Martian system,” said Markus Grebenstein, the German Space Agency’s rover program leader.
Japan isn’t the only nation pursuing scientific breakthroughs from the Martian system. China plans to launch its own Mars sample return mission in 2028, while NASA continues deliberating how to retrieve over 30 sample tubes already gathered by its Perseverance rover. Both Japan and China are currently targeting 2031 as their sample return timeline, meaning they could be closely matched in this historic race.
Japan is contributing $350 million (€308 million) to the mission. NASA is providing $87 million (€77 million), the French Space Agency $68 million (€60 million), the German Space Agency $56 million (€49 million), and the European Space Agency approximately $17 million (€15 million).