TOKYO, Japan / AsiaWire.IO / – A Japanese spacecraft has launched on a five-year journey to study Mars’ two small moons and retrieve surface samples. The Japan Aerospace Exploration Agency sent the Martian Moons eXploration spacecraft, known as MMX, into space aboard an H3 rocket launched from the Tanegashima Space Center. Liftoff occurred before dawn at 04:41 Japan time on Tuesday, October 20. The mission, expected to last five years, aims to land both a robotic spacecraft and a rover on Phobos.
Phobos, the larger and closer moon of Mars, is the primary target for this mission. MMX is anticipated to be the first spacecraft to orbit Phobos and to collect samples from its surface. Additionally, it aims to be the first mission to bring Martian system samples back to Earth. JAXA is leading this effort, collaborating with NASA, the French space agency CNES, the German Aerospace Center DLR, and the European Space Agency. The rocket launched successfully as scheduled, and spacecraft separation was later confirmed.
The primary goal of the mission is to resolve long-standing questions about the origins of Mars’ moons. One prevailing theory, the giant impact hypothesis, suggests they formed after a massive body collided with Mars. Alternatively, the capture hypothesis proposes that they are asteroids from the outer Solar System captured by Mars’ gravity. JAXA states that remote sensing and detailed analysis of the samples returned will help determine their true origins.
International partners contribute rover and scientific instruments
The small rover IDEFIX, weighing less than 30 kg, was supplied by CNES and DLR. It will land on Phobos ahead of the main spacecraft, testing how the surface reacts to mechanical action and wheeled movement. NASA contributed the MEGANE neutron and gamma-ray spectrometer, while CNES helped develop an infrared spectrometer and provides expertise in flight dynamics. The spacecraft carries a total of seven scientific instruments.
ESA provided equipment for deep space communication, including a transponder and power amplifier, and will support the mission through its Estrack network of ground stations. ESA project scientist Elliot Sefton-Nash praised Japan’s H3 launcher for performing excellently in sending the spacecraft on its trajectory. ESA Director of Science Carole Mundell congratulated JAXA and the MMX team on the successful launch.
Sample collection planned for 2031 return to Earth
The MMX spacecraft is expected to arrive at Mars roughly one year after launch, with ESA estimating its arrival next summer. It will observe Phobos from a quasi-satellite orbit and investigate potential landing sites. The spacecraft will then land, collecting at least 10 grams of surface material using a coring sampler capable of reaching regolith deeper than 2 cm, and a pneumatic sampler that pushes soil into a container with pressurized gas.
Following its surface work on Phobos, MMX will perform a flyby of Mars’ smaller moon, Deimos. It will then depart the Mars system for a roughly one-year return journey to Earth. The sample return capsule is scheduled to deliver its cargo in 2031, with recovery efforts planned in Australia. The mission was approved in 2020, initially targeted for launch in 2024, but the schedule was later shifted to 2026.