Rationalization of Thermal Simulators for Operations - Real Time Thermal Flight Correlation

This paper focuses on the rationalization of thermal simulators for operational purposes, leveraging existing thermal models and tools. By reusing thermal mathematical models throughout the satellite's lifecycle, spanning design, thermal analysis, testing, and operations, this approach aims to enhance efficiency and reduce costs. Sharing a common thermal model between analysis and operations enables spacecraft manufacturers, such as Thales Alenia Space, to streamline simulator implementation while improving accuracy. The study uses Sentinel-3 as a case study due to its flight status and well-characterized platform. The activity, supported by ESA and CNES, involved implementing a real-time spacecraft thermal simulator demonstrator based on Sentinel-3B's thermally validated model from thermal vacuum testing. This simulator addresses in-flight operational challenges such as anomaly detection and recovery testing by simulating new active thermal control strategies. Key technical challenges include telemetry recovery, initializing thermal model temperatures from telemetry, and achieving real-time performance. The simulator integrates a dynamic orbit propagator, PI-based thermal regulation, and a platform dissipator, while solving radiative and thermal equations on-the-fly even for unpredicted scenarios. The present paper details the current results of the real-time thermal flight correlation study, including replay simulations (8x faster than real time) that demonstrate performance for a hot-case scenario validated against telemetry. Additionally, the benefits of a reliable thermal simulator are discussed, including the ability to validate thermal behavior, refine margins, and correlate models during testing and flight. Potential future work, notably estimating equipment dissipation from telemetry and expanding use-case demonstrations, are detailed.