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.

While the car-sized spacecraft flew around the Mars system, flight controllers on Earth temporarily lost communication with Hera because the signal was blocked. Though the blackout was planned for the maneuver, Ian Carnelli, the European Space Agency's Hera mission manager, said it was deeply emotional.