JAXA's MMX Mission to Retrieve First Samples from Mars' Moon Phobos

Japan Aerospace Exploration Agency (JAXA) is set to launch the MMX mission from Tanegashima Space Center on October 20, 2026. The probe, massing roughly 4,480 kg with more than half its weight in fuel, will spend a year traveling to Mars, then orbit the planet for three years before descending onto Phobos, the larger of Mars' two moons. Because Phobos' gravity is far weaker than Earth's moon but stronger than asteroid Ryugu, MMX will rely on high-precision autonomous navigation and a pre-deployed IDEFIX rover—jointly built by the French and German space agencies—to identify a safe landing spot.

Once on the surface, a robotic arm and a nitrogen-gas collector will retrieve at least 10 g of material, including an estimated 0.1 % of Martian debris. The spacecraft will then depart Phobos, return to Earth, and deliver the samples by 2031, marking the first ever return of Martian-moon rocks. The $345 million mission also serves as a technology testbed for future Mars sample-return and crewed missions.