Hera spacecraft captured rare images of Deimos, one of Mars’ two moons, from 621 miles away while en route to the asteroid moonlet Dimorphos. Like our moon, Deimos is tidally locked to Mars, meaning the same side always faces the planet—the only side visible to rovers on the Martian surface.

On the way to investigate the scene of a historic asteroid collision, a European spacecraft swung by Mars and captured rare images of the red planet's mysterious small moon Deimos, the European Space Agency said Thursday.

A European spacecraft on a journey to study NASA's asteroid crash site did a quick pop-in of Mars on its way, capturing unprecedented images of Mars' lesser-known moon, Deimos. Mars has two moons, Phobos and Deimos,