The Japan Aerospace Exploration Agency (JAXA) is set to launch a Mars probe, known as the Martian Moons eXploration (MMX) mission, which aims to collect samples from Phobos, one of Mars' two moons. This mission will mark the first time that samples from a Martian moon are brought back to Earth. The probe is expected to take approximately one year to reach Mars, followed by three years of operations to collect samples, and an additional year for the return journey, with scientists anticipating the arrival of the samples in 2031.
The mission seeks to address questions regarding the formation of Mars' moons, Phobos and Deimos. Two primary hypotheses exist: one suggests the moons formed from debris resulting from a collision with Mars, while the other posits that they are captured asteroids from the outer solar system. The characteristics of the moons, including their dark color and light-reflecting properties, suggest a connection to asteroids rich in water and carbon, yet their orbits align more closely with the giant impact hypothesis.
The MMX probe will face significant technical challenges, including communication delays of up to 20 minutes between Earth and the spacecraft. The probe will have a launch mass of 4,480 kilograms (9,900 pounds), with over half of that weight allocated to fuel for its journey. After reaching Mars, the probe will jettison its outbound module and the exploration module after completing its tasks.
To land on Phobos, which has a radius of approximately 11 kilometers, the probe will utilize high-precision autonomous navigation due to the moon's low gravity. It will compare terrain data to adjust its landing approach and identify hazardous areas. The IDEFIX rover, developed by the French and German space agencies, will also be deployed to conduct a preliminary survey of Phobos before the main spacecraft lands.
Once on the surface, the probe will use a robotic arm to drill samples and a device developed by NASA to collect fine particles from the dust. The mission is estimated to cost around $345 million and represents Japan's first Mars probe launch in 28 years, aiming to advance both scientific knowledge and engineering technologies for future Mars missions. The MMX mission is scheduled to launch from the Tanegashima Space Center on October 20, 2026.