According to New Scientist, Japan's Martian Moons eXploration (MMX) spacecraft is scheduled to launch on 20 October. Its destination is Phobos, the largest moon of Mars. The spacecraft will bring back samples from Phobos, and those samples are expected to solve a moon mystery that has puzzled scientists for more than a century.
The sample return is the key to the mission's scientific promise. As New Scientist notes, the mystery has been unresolved for over 100 years. MMX's findings could therefore provide an answer that has so far remained out of reach.