The ESA Hera Mission: European contribution to the first Asteroid deflection test and full characterization of a binary asteroid

Kurzfassung

The Hera mission is under development in the ESA Space Safety Programme for launch in October 2024. Hera will contribute to the first deflection test of an asteroid with the NASA DART mission, in the framework of the international NASA- and ESA supported Asteroid Impact and Deflection Assessment (AIDA) collaboration. Once NASA DART will have performed its impact on Dimorphos, the small secondary of the binary asteroid Didymos, on September 26, 2022, Hera and its two cubesats, Juventas and Milani, will rendezvous with this binary in late 2026. It will be the first rendezvous with such a system and the first investigation of a rock as small as the 160 meter-diameter Dimorphos. Moreover, for the first time, internal and subsurface properties will be directly measured through radar sounding by the low-frequency radar onboard the Juventas Cubesat. While performing the measurements necessary to understand the effect of the DART impact on Didymos’ secondary, in particular its mass, its internal structure, the direct determination of the momentum transfer and the detailed characterization of the crater left by DART, Hera and its two cubesats will provide unique information on many current issues in asteroid science. From binary formation, small asteroid internal and surface structures, through rubble-pile evolution, impact cratering physics, to the long-term effects of space weathering in the inner Solar System, Hera will have a major impact on many fields related to our Solar System history. Additionally, those studies using Hera data will in turn affect our understanding of the asteroid population as a whole. The scientific legacy of the Hera mission will extend far beyond the core aims of planetary defense and serves as the European contribution to the international asteroid exploration era.