How and when did the idea arise that gallium nitride might be suitable for use in space?
In the early 1980’s ESA was already working with European industry and academia to perform fundamental research on gallium nitride to develop its capability for space application. As a wide bandgap semiconductor, GaN offers inherent robustness to the space radiation environment and can allow miniaturized components. This is very important for example in earth observation or telecommunications missions in order to allow maximum payload functionality.
Initially, it was not planned to integrate a component from Fraunhofer IAF. How did it end up in space?
A key aim was to understand if there were any issues preventing radio-frequency GaN devices operating reliably in space. This required extensive space environmental robustness tests to be performed. One of the test systems was an X-band MMIC (monolithic microwave integrate circuit) fabricated using the Fraunhofer IAF GaN25 process. It generated a large amount of reliability data from performing tests on ground. This extensive dataset of reliability information gave confidence to consider using the MMIC chip as part of the data telemetry transmitter on Proba-V.