Samples from a Martian moon: Japan's MMX probe set to launch for Phobos on Monday

Japan's space agency JAXA is about to launch its Martian Moons eXploration (MMX) mission. An H3 rocket is scheduled to lift the probe off from the Tanegashima Space Center on 20 October at 4:41 a.m. local time – Monday, 19 October, at 9:41 p.m. in Central Europe. According to ESA, MMX is the first mission planned to collect a sample from the Martian moon Phobos. The probe is due to reach Mars in August 2027 and enter orbit around Phobos in September 2027. Sampling is planned for no earlier than December 2028, with the capsule returning to South Australia in 2031.

In a teleconference ahead of the launch, NASA outlined its contributions. The MEGANE instrument from the Johns Hopkins University Applied Physics Laboratory will use gamma-ray and neutron spectroscopy to map which elements Phobos is made of. The P-Sampler from Honeybee Robotics, a Blue Origin company, is mounted on a landing leg and stirs up loose surface material with a short burst of pure nitrogen. NASA also supports the mission through its Deep Space Network, funds ten US scientists on the science team and will receive at least 15 percent of the samples. Program scientist Tom Statler said it will be possible to determine whether Phobos material is more consistent with an asteroid composition.

Europe is on board too: the French space agency CNES built the small Idefix rover, which is to drive on Phobos, together with the German Aerospace Center (DLR). France is also contributing the MIRS imaging spectrometer and helped plan the trajectory. The origin of Mars's two moons, Phobos and Deimos, is still debated: they could be captured asteroids or could have formed from debris of a giant impact on Mars. The samples are meant to help settle that question.