If the countdown on Tanegashima island holds, an H3 rocket will rise into the pre-dawn sky of southern Japan at 04:41 local time on Tuesday – 21:41 on Monday evening in Central Europe. On board is the Martian Moons eXploration spacecraft, MMX, and with it an ambition no space agency has fulfilled yet: to bring back soil from one of the two moons of Mars.
The target is Phobos, whose Greek name means fear; its smaller sibling Deimos stands for terror. Both are lumpy and dark, and nobody knows for sure where they came from. They could be asteroids that strayed too close and were captured by Mars, or rubble flung into orbit when something huge slammed into the planet. A handful of grams analysed in laboratories on Earth could settle the question and, along the way, reveal how water and organic material were spread through the young Solar System.
The schedule is long. Arrival at Mars is planned for August 2027, after which MMX will circle Phobos at close range. In 2029 it drops Idefix, a 25-kilogram rover built by the French and German space agencies; in the moon’s feeble gravity the vehicle will weigh barely 15 grams, less than a slice of bread. In 2030 the mother craft itself touches down to scoop at least ten grams, and a capsule is due to land in Australia in 2031.
Japan has form here: its Hayabusa probes already returned samples from two asteroids. The mission, which according to Japanese state media cost 55.3 billion yen to develop, also carries instruments from NASA and ESA. Should weather or technology force a delay, JAXA has reserved launch days until 9 November – a cushion it may value after an H3 failure in December 2025.
