Space ‘Potato’ Against Mars’ Background – Hera Station Captures Mysterious Satellite Deimos

On March 12, 2025, the European Space Agency’s Hera spacecraft performed a gravity assist maneuver near Mars, increasing its speed and adjusting its flight path to its main target, the double asteroid system Didyma and Dimorpha. The flyby of Mars was so successful that Hera was able to photograph one of the Red Planet’s most unusual satellites, Deimos, which resembles a potato tuber in its shape.

Deimos with Mars in the background. Infrared image. Image credit: ESA

Deimos’s almost perfect oval shape, its diameter of 12.4 km, and orbital parameters have long been of interest to scientists. At one time, it was assumed that Deimos could be an artificial object – an orbital Martian station or an abandoned interstellar ship. However, after a detailed study of the satellite, these bold hypotheses were refuted. Nevertheless, seeing Deimos up close, and even from the other side, is a rare stroke of luck. Usually, automatic stations designed to study Mars fly much lower than its orbit. “Hera” passed above the satellite, approaching it at a distance of about 1000 km.

During the approach to Mars, scientists tested three scientific instruments on board the station for the first time, including the Hyperscout H hyperspectral camera. This camera operates in the visible and infrared ranges at 25 wavelengths. It will be used to study the surface composition and relief of the asteroid Dimorph, which was struck by NASA’s kamikaze probe DART in 2022.

The concept of the Hera expedition

The DART mission tested the possibility of deflecting a potentially Earth-threatening asteroid with a targeted strike. After the impact, Dimorpho changed its orbit around the larger asteroid Didymos. Hera aims to record the aftermath of the impact in detail, as well as study Dimorpho’s new orbit. The data obtained will help adjust impact deflection models for asteroids that pose a threat to Earth.