Hera’s baseline payload is based on an instrument called the Asteroid Framing Camera (AFC), which will be used for guidance and navigation tasks as well as scientific observations. The AFC is an already-existing flight spare of a DLR German Aerospace Center contribution to NASA’s Dawn mission to the Asteroid Belt.
The core of the AFC is a 1024 x 1024 pixel flat panel sensor, fitted with a telescope, a filter wheel providing a panchromatic filter and seven colours in the visible and near-infrared plus an electronics box containing and data processing unit and storage.
The AFC’s operating wavelengths have been chosen to provide information about the composition of physical properties of the surface of Didymoon.
Dawn’s AFC has distinguished itself by returning remarkable images of Ceres, the single largest asteroid, and its mysterious bright spots. Now its sister camera will be surveying the smallest asteroid humankind as ever visited as well.
In addition Hera will be equipped with a compact lidar – or laser radar – to measure surface altimetry to support scientific mapping as well as support close-range asteroid operations, known as the Planetary Altimeter or PALT.
A thermal infrared instrument, TIRA, will image the asteroid in the mid-infrared spectral region to map the temperature on Didymoon's surface. From that the physical properties of its surface – such as particle size distribution and porosity – can be constrained.
The radio science experiment will use the radio link between Hera and Earth to measure the mass and the mass distribution (including internal density variations) of Didymos, and the mass of Didymoon.
The accuracy of the experiment may be increased by adding information from the inter-satellite links between Hera and the deep-space CubeSats it will deploy – representing a first for Europe.
The CubeSats will carry additional scientific instruments, complementing Hera's own payload suite, including a radar to investigate the interior of Didymoon and an imaging spectrometer and a mass spectrometer to determine the mineralogical and elemental composition of Didymos and Didymoon.