Sound test of Hera asteroid mission antenna

The High Gain Antenna of ESA’s Hera asteroid mission for planetary defence seen being prepared for testing in the acoustic reverberation chamber of the IABG test centre in Germany. This involves blasting it with launcher-level noise through the speakers seen in the wall.

Hera is Europe’s contribution to an international planetary defence experiment. Following the NASA 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.

Hera’s 1.13-m diameter High Gain Antenna will play a crucial role in mission success, by transmitting high-volume data back to Earth while receiving detailed telecommands in turn – with the mission’s Low Gain Antenna serving as backup for low data rate emergency communications.

The antenna has previously undergone radio frequency evaluation at ESA’s Compact Antenna Test Range at the ESTEC technical centre in the Netherlands before passing on to IABG in Germany for vibration testing then AAC in Austria for a stay in representative extreme-temperature vacuum conditions.

Constructed from carbon fibre, the High Gain Antenna was manufactured by HPS in Germany and Romania. It will boost Hera’s signals more than 4000-fold to reach Earth, focused down to only half a degree in the sky, so that the entire spacecraft will move in order to line up with its homeworld.

Later this year the antenna will be combined with all the rest of Hera’s subsystems, for the start of the spacecraft-scale environmental test campaign at ESA’s ESTEC Test Centre in the Netherlands, due to begin this autumn. Hera is scheduled to be launched in October 2024.