The Hera Spacecraft

Hera – named after the Greek goddess of marriage – launched on 7 October 2024 and is travelling to the Didymos binary asteroid system.The 780 m-diameter, mountain-sized main body, Didymos, is orbited by a 151 m moon, Dimorphos, about the same size as the Great Pyramid of Giza.Dimorphos is historically significant as the first object in the Solar System to have its orbit shifted by human effort in a measurable way, when NASA's Double Asteroid Redirection Test, or DART, collided with the asteroid on 26 September 2022.Hera's detailed post-impact survey of the asteroids in 2026/2027 will turn this grand-scale kinetic impact experiment into a well-understood and repeatable technique for defending Earth from potentially hazardous asteroids.

The target of ESA's Hera mission is asteroid (65803) Didymos (1996 GT), an Apollo-type rocky (S-type) near-Earth object (NEO) with a perihelion (minimum distance to the Sun) that is just below the aphelion radius (maximum distance to the Sun) of Earth orbit.

The cratered face of the Moon is mute testimony to the frequency of asteroid strikes in the Solar System. And Earth itself is hardly immune. Our homeworld has suffered upwards of three million impact craters larger than 1 km in diameter – the largest stretching more than 300 km in diameter.

ESA's Hera mission was conceived with a triple set of objectives: asteroid deflection, technology and science. The mission includes a very strong technology demonstration component.