Design, construction, and test of a reliable, redundant on-board computer (OBC) for the OUFTI-1 CubeSat of the University of Li`ege

We describe the architecture of the on-board computer (OBC) of the educational nanosatellite OUFTI-1 of the University of Liege. The OBC is the brain of the satellite. For redundancy, we quickly converged towards the use of a pair of computer boards. The issues are: What should these computers be? How should they be connected and communicate? Which one should start and continue operation for as long as possible (the “default” OBC)? How should failures be detected? How should control be passed to the “backup” OBC? Should control ever go back to the “default” OBC?