ESA’s Hera mission lifted off on a SpaceX Falcon 9 from Cape Canaveral Space Force Station in Florida, USA, on 7 October at 10:52 local time (16:52 CEST, 14:52 UTC).

Hera is ESA’s first planetary defence mission. It will fly to a unique target among the 1.3 million asteroids in our Solar System – the only body to have had its orbit shifted by human action – to solve lingering unknowns associated with its deflection.

Hera will carry out the first detailed survey of a ‘binary’ – or double-body – asteroid, 65803 Didymos, which is orbited by a smaller body, Dimorphos. Hera’s main focus will be Dimorphos, whose orbit around the main body was previously altered by NASA’s kinetic-impacting DART spacecraft.

By sharpening scientific understanding of this ‘kinetic impact’ technique of asteroid deflection, Hera should turn the experiment into a well-understood and repeatable technique for protecting Earth from an asteroid on a collision course.