A Japanese spacecraft launched toward Mars on Tuesday on a groundbreaking mission to investigate its enigmatic moons and collect samples for return to Earth.
In a collaboration involving five global space agencies, this five-year endeavor aims to land both a robotic prospector and a rover on Phobos, the larger and nearer of Mars’s two small moons.
The Japan Aerospace Exploration Agency, spearheading this ambitious sampling project, initiated the spacecraft’s launch shortly before dawn from Tanegashima Island, Japan’s primary spaceport. An hour later, officials celebrated as the spacecraft successfully detached from the rocket’s upper stage, prompting flight controllers to cheer and exchange congratulations.
While NASA has landed nine spacecraft on Mars over the last five decades and China achieved a successful landing in 2021, no mission has ever reached Phobos or its companion moon, Deimos. Additionally, no one has retrieved samples from Mars or its moons to date.
If the mission succeeds, materials such as dust, soil, and rocks from Phobos could be returned to Earth by 2031.
“There’s a lot of adrenaline, excitement, and a sense of wonder,” remarked NASA astrophysicist Tom Statler, who is part of the initiative.
Japan enters this mission with an advantage, having successfully returned samples from two asteroids previously.
Staff from the Japan Aerospace Exploration Agency and others celebrate at the Tanegashima Space Centre after a Japanese spacecraft successfully separated from an H3 rocket on Tuesday. (Naoki Hiraoka/Kyodo News/The Associated Press)
Phobos: A peculiar, small moon
Phobos is an irregularly shaped rock, roughly 22 kilometers across, resembling a lumpy potato. Studying its composition may shed light on the origins of Mars’s moons and potentially those of other celestial bodies.
Named MMX for Martian Moons Exploration, the mission has a budget of $812 million ($578 million US) and involves a substantial five-ton spacecraft expected to arrive at Mars by late next summer. The spacecraft will align with Phobos’s swift orbit around Mars before deploying a French-German rover named Idefix, after the small dog from the Asterix comics.
This image captured by NASA’s Mars Reconnaissance Orbiter shows Phobos, one of Mars’s moons, on March 23, 2008. This will be the first time any spacecraft has visited there. (NASA/The Associated Press)
Weighing no more than a microwave, Idefix will land on Phobos independently, bouncing on impact for several minutes before settling due to the moon’s extremely low gravity.
Post-landing operations for Idefix the rover
The four-wheeled rover is engineered to correct itself if it lands on its back. However, complications may arise if it sinks into soft soil or becomes trapped between boulders, according to Julien Baroukh from the French Space Agency. Once Idefix deploys its solar panels, it will be unable to self-correct, leading to a slow movement of just one millimeter per second (0.04 inches per second).
Idefix is intended to act as a “safety scout,” as it surveys Phobos for 100 days. The Japanese flight controllers are aiming to avoid soft soil and rugged terrain when the main lander, a four-legged stationary unit, descends to collect samples in late 2028 or early 2029.
The Japan Aerospace Exploration Agency showcases a spacecraft for its Martian Moons eXploration mission at the Tanegashima Space Center in Minamitane, Japan, on August 13, 2026. (Yuika Kawazoe/Kyodo News/The Associated Press)
The lander will spend just two hours on Phobos, drilling and vacuuming up at least 10 grams (one-third of an ounce) of material before launching back into space. Following this, it will conduct flybys of Deimos before departing the Martian vicinity in 2030 and racing back to Earth for a sample delivery in 2031, targeting the Australian desert.
The mission presents significant risks, with debris along the planned trajectory.
The names of the moons are rather ominous: Phobos translates to fear in Greek, while Deimos means terror. They are associated with the twin sons of Ares, the god of war (Mars in Roman mythology).
Research objectives regarding the formation of Mars’s moons
Russia faced failures in all three attempts to reach Phobos, as well as in other Mars missions. Japan’s previous Mars mission also did not achieve orbit around the red planet. Even NASA has experienced setbacks in its quest to determine whether life ever thrived on Mars.
Through the examination of Mars’s moons, researchers aim to discover whether Phobos and Deimos originated from a cataclysmic collision involving Mars and a large celestial object. Alternatively, they may have been captured asteroids drawn in by Mars’s gravitational pull.
Regardless of their origins, scientists expect to find remnants of Mars on Phobos, making these samples a valuable opportunity to understand planetary and moon formation, and potentially the conditions for life.
The insights gained will inform future Mars missions, including those involving human exploration, according to NASA’s acting planetary science director, Lindsay Hays.
“This is a once-in-a-lifetime opportunity. We are part of the inaugural sample return mission from the Martian system,” stated Markus Grebenstein, rover chief at the German Space Agency.
Japan is not alone in pursuing the scientific treasures contained within the Martian system’s materials. China is planning its own sample return mission to Mars in 2028, while NASA is currently deliberating on how to retrieve over 30 sample tubes collected by the Perseverance Mars rover, which is now the leading vehicle for off-Earth exploration.
Japan and China could be in a close race to bring back samples from Mars, both aiming for 2031.
Japan is allocating $350 million to this mission, while NASA is investing $122 million ($87 million US), the French Space Agency about $95 million ($68 million US), the German Space Agency roughly $79 million ($56 million US), and the European Space Agency around $24 million ($17 million US).