TOKYO, Japan / AsiaWire.IO / – The Japan Aerospace Exploration Agency has initiated a mission to explore Mars’ two small moons and collect samples, with its spacecraft now en route. The Martian Moons eXploration spacecraft, known as MMX, was launched on an H3 rocket from the Tanegashima Space Center, taking off just before dawn at 04:41 Japan time on Tuesday, October 20. The mission, scheduled for five years, aims to land a robotic spacecraft and a rover on Phobos.
Phobos, the larger and nearer of Mars’ two moons, is the primary target. MMX is anticipated to become the first spacecraft to orbit Phobos and to retrieve samples from its surface. Additionally, it aims to be the first mission to bring material back to Earth from the Mars system. JAXA is leading this international effort, collaborating with NASA, the French space agency CNES, the German Aerospace Center DLR, and the European Space Agency. The launch proceeded as planned, and spacecraft separation was subsequently confirmed.
The core objective of the mission is to shed light on the origins of Mars’ moons. The giant impact hypothesis suggests they formed after a colossal collision with Mars, whereas the capture hypothesis proposes they are asteroids from the outer Solar System captured by Mars’ gravity. JAXA states that remote sensing and detailed analysis of the returned samples will help determine their true origins.
International partners contribute rover and scientific instruments
CNES and DLR supplied a small rover called IDEFIX, weighing under 30 kg. This rover will land on Phobos before the main spacecraft, testing how the surface reacts to mechanical interaction and wheeled movement. NASA contributed a neutron and gamma-ray spectrometer called MEGANE. CNES also helped develop an infrared spectrometer and provides expertise in flight dynamics. The spacecraft carries a total of seven scientific instruments.
ESA contributed deep space communication equipment, 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 outstanding performance in sending the spacecraft on its journey. Carole Mundell, ESA Director of Science, congratulated JAXA and the MMX team on the successful launch.
Sample retrieval scheduled for 2031 after Mars orbit
Following its launch, MMX is expected to reach Mars approximately one year later, with ESA estimating arrival next summer. The spacecraft will orbit Phobos in a quasi-satellite orbit, surveying potential landing sites. It will then land, collecting at least 10 grams of surface material. A coring sampler on a robotic arm can reach beneath the surface to depths over 2 cm, while a pneumatic sampler uses pressurized gas to push soil into a container.
Post-sampling, MMX will observe Mars’ smaller moon, Deimos, during a flyby. It will then depart the Mars system, embarking on a roughly one-year return journey to Earth. The sample return capsule is scheduled to deliver its cargo in 2031, with recovery planned in Australia. The mission was approved in 2020 and was initially targeted for a 2024 launch, but the schedule was later moved to 2026.