Accurate models of non-gravitational accelerations of the BepiColombo spacecraft during solar conjunction experiments

This thesis outlines a method to quantify and analyze the role of non-gravitational forces and relative accelerations that affect a spacecraft in an interplanetary mission, specifically the “BepiColombo” project. A study from the University La Sapienza of Rome by Di Stefano et al. was used as a guideline in identifying which perturbations are the most prominent in the cruise phase and in setting up the model. Listed by decreasing order of magnitude, these are: Solar Radiation Pressure, Thermal Recoil Pressure, Solar Wind Dynamical Pressure and Radio Emission Recoil Pressure. The ultimate goal of this research is to create a reliable and accurate model that can be used to validate the BepiColombo Radio Science experiments, which require the utmost precision and for which the on-board accelerometer can only be partially relied upon. This study and its practical products, the "PyForces" used in the MONTE orbit determination software, will also act as a benchmark for successive models that will cover the Mercury Orbit phase of the mission, which will be crucial for the evaluation of Mercury’s gravitational field and rotational state – one of the strategic goals of the entire BepiColombo mission.