Hera spacecraft
Powered by two 5-m long solar arrays with a hydrazine bipropellant propulsion system, Hera is a relatively small-scale mission in interplanetary terms. The spacecraft has a box-shaped body built up of aluminium honeycomb panels with a central carbon-fibre reinforced polymer tube that also contains Hera's propellant tanks.
Hera measures approximately 1.6 m across per side, plus solar arrays that stretch 11.5 m across when fully deployed. The spacecraft is roughly the size of a small car and weighs in about 1081 kg fully fuelled.
(A) Asteroid Deck - Hosting all onboard instruments.
(B) Reaction Control Thrusters - Two placed on each corner of the Hera spacecraft, adding up to 16 10- Newton hydrazine bipropellant thrusters in all, firing individually as required to reorient the spacecraft, for instance to line up its High Gain Antenna with Earth.
(C) High Gain Antenna, HGA- This 1.13-m diameter X-band antenna is the Hera mission's main means of receiving commands and sending back data with the necessary volume. The antenna boosts Hera signals more than 4000-fold to reach Earth, focused down to only half a degree. Coupled with an innovative deepspace transponder, the HGA will also perform science in its own right. Doppler shifting in its signals due to gravity will be used to derive the mass and shape of the asteroid.
(D) Low Gain Antenna, LGA - Omnidirectional Low Gain Antenna for back-up, low data rate communications. A second LGA is positioned on the spacecraft's aft side
(E1 & E2) Solar Arrays- Two 5-m long wings, made up of three hinged panels each, adding up to 14 square metres, with more than 1600 solar cells.
(F) Orbit Control Thrusters - Oriented in a circle on Hera's underside, these six 10-Newton hydrazine bipropellant thrusters are fired three at a time for spacecraft manoeuvres and orbital changes.
