The geodesy of Mercury with the missions MESSENGER and BepiColombo

The work is organized in six chapters. Chapter 1 introduces briefly the exploration of Mercury highlighting the generic characteristics of the planet and its research with space probes. Chapter 2 is focused on the orbit determination for the geodesy of Mercury. We present here the overall description of radio science experiments, showing the measurements and the geodetic models, and the codes of the orbit determination for interplanetary spacecraft. Chapter 3 describes the MESSENGER mission and radio science experiment. Here, we report on the analysis of the radio tracking data showing the orbit reconstruction and the estimated model of the Hermean gravity field and ephemeris. Chapter 4 is about the mission BepiColombo and the Mercury Orbiter Radio science Experiment. We carried out a new set of numerical simulations that provides attainable accuracies in the gravity field estimation. Chapter 5 summarizes the consequences of the estimated Hermean gravity field on the geodesy of the planet and the orbit evolution of the BepiColombo spacecraft. Chapter 6 gives conclusions about our work.