ESA’s Hera reaches asteroid system to study 2022 impact

The European Space Agency’s Hera spacecraft arrived at the Didymos asteroid system on Wednesday, beginning a close-up study of the effects of a 2022 spacecraft impact designed to test whether an asteroid’s path can be changed.

The system is nearly 200 million kilometres from Earth. Hera will examine Didymos, about 800 metres across, and its smaller companion Dimorphos, about 160 metres wide. A Dutch-built camera is among the instruments aboard.

In September 2022, NASA’s DART spacecraft deliberately struck Dimorphos, changing its course slightly. The pair poses no danger to Earth, but the test was intended to help assess whether a hazardous asteroid could one day be deflected.

Hera’s arrival follows its first images showing Didymos and Dimorphos as separate objects. The spacecraft is expected to investigate the impact site and how the collision changed Dimorphos, questions that remain open after DART’s test. Hera’s first image of the pair marked an earlier step in that investigation.