Japan Launches Mission to Mars' Mysterious Moons

A Japanese spacecraft launched Tuesday on a five-year mission to explore the mysterious moons of Mars, with the ambitious goal of collecting samples from Phobos and returning them to Earth by 2031. The Japan Aerospace Exploration Agency (JAXA) led the mission, named Martian Moons Exploration (MMX), launching the spacecraft before dawn from its spaceport on Tanegashima Island.

Officials confirmed the mission's success about an hour after liftoff when the spacecraft separated as planned from the rocket's upper stage, eliciting applause and celebration from flight controllers. This endeavor marks a significant step in space exploration, as no previous mission has successfully collected samples from Mars or its moons.

While NASA has landed multiple spacecraft on Mars and China achieved a touchdown in 2021, neither agency, nor any other, has reached Phobos or its companion moon, Deimos. The MMX mission seeks to change this by landing a robotic prospector and a rover on Phobos, the larger of the two moons.

Phobos, described as a lumpy, potato-shaped rock approximately 22 kilometers (14 miles) across, presents a unique opportunity to study the formation of Mars' moons and potentially moons elsewhere in the solar system. Scientists hypothesize that Phobos and Deimos may have formed from debris after a collision between Mars and an asteroid, or they could be captured asteroids. Samples from Phobos could offer insights into these processes and the early solar system.

The approximately $578 million MMX mission involves a 5-ton spacecraft expected to reach Mars by late next summer. Once in orbit, it will deploy the French-German rover named Idefix. This small rover, no larger than a microwave oven, is designed to land on Phobos, bounce in its low gravity, and self-right if it lands upside down. Its primary role is to scout for safe landing sites for the main lander.

After Idefix has completed its approximately 100-day exploration, the main MMX spacecraft, a stationary lander, will descend to the Martian moon's surface in late 2028 or 2029. It is scheduled to spend two hours gathering at least 10 grams (one-third of an ounce) of material before ascending back into space. The mission will also conduct flybys of Deimos before departing the Martian system in 2030 and returning to Earth in 2031, with sample delivery planned for the Australian desert.

This undertaking is particularly challenging given the moons' names, Phobos (fear) and Deimos (dread), and the history of failed Mars missions, including Russia's multiple attempts at Phobos. Japan itself previously failed to place a spacecraft into orbit around Mars.

Scientists are eager to analyze the collected samples, which could provide answers about the formation of Mars' moons, the conditions on early Mars, and potentially the origins of life. The data gathered is expected to inform future Mars exploration efforts, including crewed missions.

Japan's mission is part of a growing international interest in Mars sample return. China plans its own sample return mission for 2028, and NASA is still evaluating methods to retrieve samples collected by its Perseverance rover. Both Japan and China are targeting a 2031 return for their missions, setting up a potential scientific race.

The MMX mission is a collaborative effort, with significant contributions from multiple space agencies. Japan is investing $350 million, NASA is contributing $87 million, the French Space Agency approximately $68 million, the German Space Agency about $56 million, and the European Space Agency $17 million.