HERA Photovoltaic Assembly — Low Intensity Characterisation of Large Area Triple-Junction Solar Cells

The European Space Agency's HERA mission aims to explore the Didymos and Dimorphos asteroid system after the DART mission's kinetic impact. Operating the HERA spacecraft at a distance of 2 astronomical units from the Sun presents challenges for photovoltaic assembly, and the development of a robust PVA, capable of performing in low temperature and low intensity conditions (LILT), is crucial to the mission's success. In the framework of the HERA mission, Leonardo performed a dedicated Type Approval Test (TAT) to validate critical manufacturing processes on
$6\times 12\ \text{cm}^{2}$
AZUR 3G30 solar cells and to characterize these solar cells assemblies in LILT conditions. In particular, the LILT characterization performed was aimed at investigating the temperature coefficients trend of such solar cells. For qualification, a DVT has been developed and a dedicated test campaign has been performed, aimed at qualifying the Leonardo's PVA materials and process. During the DVT test campaign, Leonardo's capabilities of performing low intensity flasher tests was assessed, allowing to perform low intensity characterization on both DVT and flight panels.