Japan Launches Robotic Mission to Retrieve Samples From Martian Moon

The Japan Aerospace Exploration Agency launched a spacecraft toward Mars on October 20, 2026, beginning a five-year mission to land on the moon Phobos and return soil samples to Earth.

The H3 rocket lifted off from the Tanegashima Space Center in southern Japan before dawn, successfully separating from the spacecraft’s upper stage approximately one hour later.

The $578 million mission, known as Martian Moons eXploration, seeks to determine whether Phobos is a captured asteroid or a remnant of a massive collision with the Martian surface.

“There’s a lot of adrenaline and a lot of excitement and a lot of wow,” said NASA astrophysicist Tom Statler, who is involved with the project.

The spacecraft is expected to reach the Martian system by late 2027, where it will conduct high-resolution imaging and topography measurements of Phobos and its smaller companion, Deimos.

The mission will deploy a small French-German rover named Idefix, which is designed to navigate the moon’s low-gravity environment to scout for safe landing sites for the primary mothership.

“All bets are off, though, if it sinks into soft soil or gets wedged between rocks,” said the French Space Agency’s Julien Baroukh regarding the rover’s landing risks.

Idefix will move at a speed of 1 millimeter per second during its 100-day mission to identify terrain suitable for the mothership to collect surface samples in 2028 or 2029.

Japan previously demonstrated the ability to perform proximity operations and sample retrieval through its Hayabusa asteroid missions, providing a technical foundation for the current expedition.

Scientists believe the returned samples, which are expected to arrive on Earth in 2031, could contain evidence of ancient Martian climate conditions or traces of past biological activity.

The primary challenge remains the moon’s low escape velocity and the engineering complexity of landing on a body with a diameter of only 22 kilometers.