On 20 October 2026, Japan’s H3 rocket lifted off from the Tanegashima Space Center, carrying the Martian Moons eXploration (MMX) probe. The launch marks the first step toward a historic round‑trip to Mars’s moon Phobos.

After launch, MMX will travel toward Mars, enter orbit around Phobos and spend three years in the Martian system. During that time it will collect at least 10 grams of surface material from the moon.

The mission’s main scientific aim is to find out how Phobos and Deimos formed. JAXA said the probe will test the giant‑impact hypothesis against the capture hypothesis for the moons’ origin.

Samples returned to Earth are expected to deliver paradigm‑shifting science, according to NASA Science Mission Directorate administrator Nicky Fox. JAXA also hopes the data will show whether Phobos could serve as a natural space station for future crewed Mars exploration.

MMX is a joint effort of Japan’s JAXA, U.S. and European space agencies, universities and technology companies, linking international expertise to a common goal. If successful, the mission could reshape our understanding of the Solar System and pave the way for human journeys to Mars.