While performing yesterday’s flyby of Mars, ESA’s Hera mission for planetary defence made the first use of its payload for scientific purposes beyond Earth and the Moon. Activating a trio of instruments, Hera imaged the surface of the red planet as well as the face of Deimos, the smaller and more mysterious of Mars’s two moons.

Launched on 7 October 2024, Hera is on its way to visit the first asteroid to have had its orbit altered by human action. By gathering close-up data about the Dimorphos asteroid, which was impacted by NASA’s DART spacecraft in 2022, Hera will help turn asteroid deflection into a well understood and potentially repeatable technique.

Hera’s 12 March flyby of Mars was an integral part of its cruise phase through deep space, carefully designed by ESA’s Flight Dynamics team. By coming as close as 5,000 km away from Mars, the planet’s gravity shifted the spacecraft’s trajectory towards its final destination, Dimorphos and the larger Didymos asteroid it orbits around. This manoeuvre shortened Hera’s journey time by many months and saved a substantial amount of fuel.