The Japan Aerospace Exploration Agency (JAXA) is preparing an uncrewed mission to the moons of Mars. The MMX (Martian Moons eXploration) spacecraft is to become the first expedition in history to return samples from the vicinity of the Red Planet. The launch of an H3 rocket from the Tanegashima spaceport is scheduled for Tuesday at 4:41 a.m. local time (Monday evening GMT).
The project is being carried out jointly with NASA, the European Space Agency, the French National Centre for Space Studies (CNES), the German Aerospace Center (DLR), as well as about 20 universities and technology companies. According to MMX project leader Yasuhiro Kawakatsu, this will be the "first round trip" to the Martian system.
The probe will arrive at Mars around August next year. It will then enter orbit around Phobos, one of the planet's two moons, and land to collect at least 10 grams of surface material. Three years of work in the Martian system are allotted for all of this. Before landing, a small rover, IDEFIX (named after the dog in the French Asterix comics), will drive across the surface and carry out observations to select a safe landing site.
Scientists hope to understand how Mars and its moons formed. There are two main hypotheses: the "giant impact" hypothesis (the moons formed after a celestial body struck Mars) and the "capture" hypothesis (they are asteroids pulled in by the planet's gravity). Establishing the truth will help understand how an environment suitable for life could have formed on the rocky planets - Mercury, Venus, Earth and Mars. French astrophysicist Patrick Michel, who is involved in the project, noted that if Phobos and Deimos really are remnants of early "deliveries" of material from the outer Solar System, they may preserve traces of materials important for the emergence of life.
The main difficulty is Phobos's weak gravity. It is so low that engineers had to specially design landing legs. In addition, to return, the spacecraft will have to escape Mars's "gravity well." Phobos orbits at a distance of about 6,000 kilometers from the planet's surface. Japan already has experience in sample delivery: in 2020, the Hayabusa-2 probe brought back 5.4 grams of soil from an asteroid. China, for its part, plans to launch the Tianwen-3 mission around 2028 and return Mars samples by 2031. The American program to return samples collected by the Perseverance rover was effectively canceled after a vote in Congress in January.
For now, this is only a scientific mission: the use of Phobos as a "natural space station" for future crewed flights to Mars is only being studied. One limitation is that the mission will not be able to land on the second moon, Deimos - it is planned only to observe it from a flyby trajectory.