TOKYO, Japan / AsiaWire.IO / – A spacecraft from Japan has embarked on a journey to Mars with the goal of investigating its two small moons and retrieving samples. The Japan Aerospace Exploration Agency launched the Martian Moons eXploration spacecraft, known as MMX, using an H3 rocket from the Tanegashima Space Center. The launch occurred just before dawn at 04:41 Japan time on Tuesday, October 20. This five-year mission plans to deploy both a robotic lander and a rover on Phobos.
Phobos, the larger and nearer of Mars’ two moons, is the primary target. MMX aims to become the first spacecraft to orbit Phobos and to gather surface samples, as well as the first mission to return material to Earth from the Mars system. JAXA leads this international effort, working alongside NASA, CNES, DLR, and the European Space Agency. The launch was successful, and spacecraft separation was subsequently confirmed.
The main scientific question revolves around the origins of Mars’ moons. The giant impact hypothesis proposes they formed from a collision with Mars, whereas the capture hypothesis suggests they are asteroids from the outer Solar System that Mars captured through gravity. JAXA expects that remote sensing and detailed analysis of the samples will help determine their true origin.
International collaborations provide rover and scientific tools
CNES and DLR contributed a small rover named IDEFIX, weighing under 30 kg. This rover will land on Phobos before the main spacecraft, testing wheeled mobility and studying surface responses to mechanical interactions. NASA supplied a neutron and gamma-ray spectrometer called MEGANE, while CNES also helped develop an infrared spectrometer and offers expertise in flight dynamics. Overall, the spacecraft carries seven scientific instruments.
ESA supplied deep space communication hardware, including a transponder and power amplifier, and will support the mission through its Estrack ground station network. ESA project scientist Elliot Sefton-Nash praised Japan’s H3 launcher for its excellent performance. ESA’s Director of Science, Carole Mundell, congratulated JAXA and the MMX team on the successful launch.
Sample retrieval planned for 2031 after Mars approach
The spacecraft is expected to arrive at Mars roughly a year after launch, with ESA estimating a summer arrival. It will orbit Phobos in a quasi-satellite path, surveying potential landing sites, before descending to collect at least 10 grams of surface material. A robotic arm equipped with a coring sampler can reach depths greater than 2 cm into the regolith, while a pneumatic system uses pressurized gas to push soil into a container.
Following its surface work on Phobos, MMX will perform a flyby of Deimos, Mars’ smaller moon. The spacecraft will then depart Mars’ vicinity for a one-year journey back to Earth. The sample return capsule is scheduled to deliver its cargo in 2031, with recovery operations planned in Australia. The mission, approved in 2020, was initially targeted for launch in 2024 but was rescheduled to 2026 before the current timeline.