The Japan Aerospace Exploration Agency is preparing to launch a spacecraft on a mission to bring back soil samples from Phobos, the larger potato-shaped moon orbiting Mars. Scheduled to lift off from the Tanegashima Space Center, the international endeavor relies on Japan’s H3 rocket and features hardware contributions from NASA and European space agencies.
Launching the H3 Rocket Toward Mars
The Martian Moons eXploration mission is slated for liftoff, aiming to reach the Martian region by August 2027. Packed aboard the craft will be 13 scientific instruments—featuring a French-German lander rover, a Nasa gamma-ray measuring tool alongside a sampling device, and the European Space Agency’s deep space communication apparatus. After arriving in the Mars system, the spacecraft will survey the moons before a planned return to Earth in 2031.
Phobos measures about 27km (17 miles) in diameter at its widest point. Its gravity is about 0.1% the gravitational pull that Earth does. This ultra-low gravity creates significant engineering hurdles for landing and surface mobility.
Engineering the First Wheel-Driven Low-Gravity Rover
Before the main spacecraft attempts its sampling operations, a joint French, German, and Japanese robotic rover named Idefix will touch down on Phobos. The 25-kilogram rover will be the first to conduct wheeled driving on an ultra-low gravity body. Because of the minimal gravitational pull, the rover’s effective weight on the moon will be 12 grams.
The mission builds on lessons learned from past international failures. Russia tried this in 2011 with its Phobos Grunt mission. Following its successful liftoff into low Earth orbit, the vehicle was unable to ignite its thrusters to set a course for Mars. Japan, however, previously demonstrated deep-space sample return capabilities through its Hayabusa space missions.
Collecting Samples With Dual Technology
Once surface data is transmitted, the main spacecraft will land to collect at least 10g (0.35oz) of soil using two distinct collection methods. NASA contributed a Pneumatic Sampler developed by Honeybee Robotics, a Blue Origin company. The P-Sampler uses high-pressure nitrogen gas to blow surface dust into a sealed canister in a fraction of a second. This system complements JAXA’s own coring method, which is designed to extract material from a depth of about 2cm.
Approximately 15% of all brought-back specimens will be received and managed by NASA at Houston’s Johnson Space Center Astromaterials Lab. Nicky Fox, associate administrator, Science Mission Directorate, NASA Headquarters in Washington, stated that the samples will bring forth paradigm-shifting science for generations, as NASA prepares to send the first humans to Mars.
Unresolved Origins of the Martian Moons
Scientists remain divided on how Phobos and Deimos formed. Some researchers theorize the irregular bodies are debris remnants left after a large object collided with Mars. Others suggest the moons could be asteroids that have come from elsewhere. Researchers hope that analyzing the chemical composition of the returned soil will resolve these competing theories, while also providing data that can help a future manned Mars exploration.
