For an hour, HERA flew as close as 5,600 kilometers from the Martian surface, at a speed of 33,480 kilometers an hour. It used the opportunity to test some of its scientific instruments, snapping around 600 pictures, including rare ones of Deimos.

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. The only way to see Deimos’ far side up close is for a probe like Hera to fly behind it, making such images more of a rarity.

A mission to survey the results of a deliberate crash between an asteroid and a NASA spacecraft has taken stunning images of Mars and its moon Deimos