Japan Launches MMX Spacecraft to Retrieve Samples from Phobos

Japan launched its Martian Moons eXploration (MMX) spacecraft on an H3 rocket on Oct. 20 from the Tanegashima Space Center, aiming to retrieve samples from the Martian moon Phobos and return them to Earth by July 2031, according to reports from KBS News and the Japan Aerospace Exploration Agency (JAXA). JAXA announced that the liftoff occurred precisely at 4:41:3 a.m. on Oct. 20.

MMX Spacecraft Enters Transfer Orbit Toward Mars

The MMX spacecraft separated from the H3 rocket 10th vehicle roughly one hour and 11 minutes after liftoff, successfully entering its designated transfer orbit toward Mars, KBS News reported. During the ascent, the H3 rocket jettisoned four booster rockets and the first-stage rocket sequentially to increase altitude. According to an announcement from JAXA, the agency verified that the spacecraft’s core systems—including its solar array power generation, attitude control systems, and ground communication links—are functioning normally as the probe adjusts its onboard equipment for the journey. Japan is pursuing the mission as an international joint exploration project.

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Mission Objectives at Phobos

The MMX probe is scheduled to reach the vicinity of Mars in August 2027 and enter a surrounding orbit to conduct a multi-year investigation, according to JAXA schedules. Following arrival, the mission will spend three years performing activities that include exploring Phobos. Before collecting physical material, a specialized rover designed to operate within the extremely low gravity environment of Phobos will survey the moon’s surface. The spacecraft aims to extract approximately 10 grams of soil from Phobos and dispatch the sample container back toward Earth. Hiroshi Yamakawa, Chairman of the Japan Aerospace Exploration Agency (JAXA), stated: We will work closely with affiliated organizations inside and outside Japan and put all our efforts into smoothly executing the MMX mission, securing new knowledge that will contribute to the development of planetary science, and securing foundational technologies that will support future space exploration. Phobos is a satellite measuring 20 to 30 kilometers in diameter, which is less than one-hundredth the size of Earth’s Moon. Regarding its origins, two theories exist: one suggests that a passing planet became captured to orbit Mars, while the other suggests it formed from fragments broken apart when a celestial body collided with Mars. The collected samples are expected to preserve material originating from Mars itself, providing clues to the formation of Phobos, Mars, and the solar system.

Mission Milestones and Timelines