Pseudo Drag-Free System Simulation for Bepicolombo Radio Science Using Accelerometer Data

The Mercury Orbiter Radio science Experiment on-board the European Space Agency/Japan Aerospace Exploration Agency (ESA/JAXA) BepiColombo mission aims at determining the gravity field and the rotational state of the planet to provide insights into its internal structure, and at performing tests of General Relativity. The experiment will rely on accurate radiometric data provided by the on-board Ka-band transponder and on measurements of the non-conservative perturbations acting on the spacecraft, provided by the Italian Spring Accelerometer. This paper presents a software implementation of a pseudo drag-free system which includes the accelerometer measurements in the orbit determination process. Numerical simulations focus on the identification of a suitable calibration strategy to fulfil the experiment goals pertaining to geodesy and geophysics. The achievement of the expected scientific results will depend meaningfully on the quality of the accelerometer data.