Data-driven thermal state estimation for in-orbit systems via physics-informed machine learning

Thermal analysis of spacecraft systems is a critical process for mission operations. However, knowing the tem-perature distribution of entire systems is not easy due to the uncertainty of the thermal mathematical model (TMM) and limited temperature sensors. This paper proposes a temperature estimation method using physics -informed machine learning (PIML). The PIML-based thermal analysis allows us to estimate the actual temper-ature distribution by seamlessly bridging the limited observations and the TMM. To evaluate the estimation accuracy of the proposed method, we conducted a numerical experiment using a pseudo small satellite model consisting of 100 nodes. The proposed method was applied to three different model error cases and was found to improve temperature estimation accuracy in all cases. In addition, the impact of the number of temperature sensors and their placement on estimation accuracy was investigated.