How did Mars get its moons? Japan's MMX space mission aims to solve the puzzle - Phys.org

The Earth got its Moon when a celestial object collided with our planet more than four billion years ago. This impact hurled molten rock into space, which eventually coalesced to form the satellite we can see every night from across our planet. But what of our neighbour, Mars? The red planet has two small, irregularly shaped moons called Phobos and Deimos. There are several theories on how these natural satellites formed, but no clear front-runner. Soon, a Japanese-led space mission called Martian Moons Exploration (MMX) will begin its hunt for the answer.

A Japanese space mission is about to launch towards Mars. But it will not land on the planet itself. Instead, the Martian Moons Exploration (MMX) mission will focus on Phobos, the bigger of Mars’s two small moons. The mission will lift off on Monday October 19 at 20:41 BST on an H3 rocket from the Tanegashima Space Center, in the south of Japan.

Mercury remains one of our solar system’s most elusive and difficult planets to study. It's easier to send probes to the icy moons of Saturn or Jupiter, or even Pluto, than to land on our innermost planet of Mercury. Ground-based optical observatories don’t risk turning their sights on Mercury, without potentially damaging their optics under the very nearby glare of the bright Sun. Thus, of the planets in our inner solar system, Mercury arguably remains both the least explored and most misunderstood.