ESA’s Hera asteroid mission for planetary defence seen with one of its two solar wings added, during its continuing test campaign at the ESTEC Test Centre in the Nethelands.

The van-sized spacecraft, left, is powered by a pair of solar array wings, made up of three panels each, provided by Beyond Gravity in Switzerland.

One of these 5-m-long wings was added for Hera’s ‘cold deployment check’ – a manual unfolding process to confirm that the wing fits correctly. Because the solar wings have been designed to operate in weightlessness they were supported by a frame during this test deployment.

Hera is Europe’s contribution to an international planetary defence experiment. Following the DART mission’s impact with the Dimorphos asteroid last year – modifying its orbit and sending a plume of debris thousands of kilometres out into space – Hera will return to Dimorphos to perform a close-up survey of the crater left by DART. The mission will also measure Dimorphos’ mass and make-up, along with that of the larger Didymos asteroid that Dimorphos orbits around.