Eclipse Prediction Algorithms for Low-Earth-Orbiting Satellites

Earth-orbiting satellites experience a partial or full eclipse when they pass through the night side of the Earth. These eclipse events can have significant impacts on the satellite due to the dramatic change of the solar radiation incident. It is therefore essential to propose a high-precision eclipse prediction algorithm or even a space-borne algorithm applied to the satellite to predict the eclipse events autonomously. This paper proposes two eclipse prediction algorithms based on an atypical eclipse condition. The first is the numerical variable-step algorithm whose computation efficiency is superior to the previous fixed-step algorithm due to adopting multiscale step sizes. The other is the autonomous space-borne algorithm, which, based on the analytical solution of the eclipse condition, predicts the penumbra and umbra. Both algorithms have been implemented to the Sun-synchronous orbit and the prediction results are compared with that of the Satellite Tool Kit software. It is indicated that the numerical variable-step algorithm is of high prediction accuracy, whereas the autonomous space-borne algorithm is more suitable for the on-board processor to predict the eclipse due to its reduced computational demands.