HOPAS (Hybrid online policy adaptations strategy) on OPS-SAT

While AI technologies have shown promise in various applications in the space industry, their adoption within spacecraft flight software has yet to happen in a significant manner. This is due to a number of factors, including the relatively low computing power available onboard traditional spacecraft, the long development process required in the industry and the lack of opportunities for in-orbit demonstrations. In ESA's OPS-SAT satellite, Airbus teams identified a unique opportunity to quickly test promising algorithms in orbit as the industry seeks to resolve the issues listed above.As part of ESA's 2021 Open Space Innovation Platform (OSIP) call for ideas to experiment with OPS-SAT, Airbus teams submitted the Hybrid Online Policy Adaptation Strategy (HOPAS) concept. HOPAS uses an AI technique called Reinforcement Learning (RL) in an online fashion to continuously improve the attitude control performance of a space system and adapt to its environment. It has been prototyped in a representative simulator of ESA's Solar Orbiter spacecraft and it has shown promising performance. This led to an activity that lasted throughout 2022 to adapt the algorithm to the specificities of OPS-SAT.