Martian moon Deimos seen crossing the face of Mars in this sequence of Thermal Infrared Imager images acquired during the Hera mission's gravity-assist flyby of Mars on March 12, 2025.

The results of Hera's flyby could ultimately tell us whether Deimos is a captured asteroid or made from debris from a giant impact on Mars. Europe's Hera mission, on its way to the Didymos ...