Precise modelling of solar and thermal accelerations on Rosetta

This paper presents an analytical approach for the high-fidelity model of the accelerations induced by the Solar Radiation Pressure (SRP) and the Thermal Recoil Pressure (TRP) on ESA’s Rosetta spacecraft. The relevant gravitational forces that are induced by planets, moons, and asteroids can readily be incorporated for predicting interplanetary trajectories. However, there are additional perturbation forces that cause residual errors in the orbit determination process. These are the so-called “small forces”, which are mainly induced by the SRP and TRP effects and are often not modelled adequately or not completely. In the case of deep-space missions, the spacecraft travels a wide range of distances relative to the Sun. This makes the spacecraft exposed to a wide range of solar fluxes and surface temperatures. This paper establishes a high-fidelity acceleration model, which enables more precise orbit predictions for interplanetary spacecraft. The application of the model is demonstrated and validated using the orbit determination data and in-flight temperature data of the Rosetta spacecraft.