Precise orbit determination for the orbital phase of BepiColombo

The BepiColombo spacecraft, designed by ESA and JAXA, is expected to begin its scientific phase in orbit around Mercury in early 2027. Among the scientific investigations is the Mercury Orbiter Radio-science Experiment (MORE), which will exploit a multi-frequency microwave tracking system with an advanced Ka-band transponder to achieve its objectives related to Mercury’s geodesy and fundamental physics. Building on the legacy of the MESSENGER mission, MORE aims to expand and refine our knowledge of the planet’s geophysical properties. This thesis supports the preparation of the MORE geodesy investigation during BepiColombo’s orbital phase through three complementary tasks. First, an independent reanalysis of the complete MESSENGER two-way Doppler radiometric dataset is carried out to provide a reliable basis for a future joint analysis with MORE data. Second, numerical simulations of MORE are conducted to evaluate its performance under realistic dynamical modelling errors and in combination with MESSENGER data. Finally, a ray tracing software package for advanced modelling of non-gravitational accelerations is validated, demonstrating its potential for the orbit determination of future missions such as BepiColombo.