Phd in AERONAUTICS AND SPACE ENGINEERING

Thesis title: Use of radio science and navigation data for the construction of planetary ephemerides

The central theme of the thesis concerns the exploitation of radio tracking measurements for the development of planetary ephemerides, in particular, applied on two research topics: 1) the analysis of navigation data of the Cassini mission to enhance the ephemeris of Saturn and to increase our knowledge of the outer Solar system; 2) the simulation of BepiColombo measurements collected during the orbital phase at Mercury, for assessing their potential contribution on the INPOP planetary ephemerides. The first research aims at reprocessing Cassini radio tracking data by exploiting the current knowledge of the Saturnian system developed throughout the mission, i.e. the availability of accurate satellite ephemerides and precise gravity solutions for Saturn, Titan and the other major moons. This allows the production of more precise normal points, which are able to constrain the orbit of the planet at meters-level for 13 years (almost half of its revolution) and to provide invaluable insights on the mass of the Kuiper belt. The results show a reduction of a factor four on normal points uncertainties with respect to previous analyses, providing tighter constraints on the acceptance regions of the Planet 9 as well. The second research topic focuses on the end-to-end simulations of BepiColombo MORE experiment, aimed at assessing the achievable accuracy on the MPO orbit reconstruction. A thorough study of MORE capabilities, through a realistic covariance analysis, is in fact fundamental to evaluate BepiColombo contribution on planetary ephemerides, since the uncertainties of Mercury’s normal points are deduced from the mapped covariance of the spacecraft state.