Development of methods for the global ephemerides estimation of the gas giant satellite systems

The satellite systems of Saturn and Jupiter are complex dynamical systems, with several interactions happening between the central body, its rings and the natural satellites. During the last two decades, unmanned probes allowed to study the gas giant satellite systems. The three most relevant spacecrafts to their study have been Galileo, Cassini and Juno. Galileo studied the Jupiter system, the primary body and the main moons during 8 years, despite the failure on the deployment of its high gain antenna that limited the science retrieval. Cassini, analogously, studied during most of the 13 years of its mission, the natural satellites, paying specific attention to Titan. Then, in 2017 both Cassini and Juno spacecrafts were used to carry out gravity measurements of Saturn and Jupiter. Both spacecraft were inserted into similar, almost polar, highly eccentric orbits with low pericenter altitudes. Tracking the motion of the probes during pericenter passes from the DSN enabled the retrieval of the gravity field of both gas giants at an unprecedented level of accuracy. These results provide constraints on the interiors of the gas giants, but also, on the satellite system ephemerides which, analogously, hold information on the properties and evolution of both the satellites themselves and the central body. The main aim of this project is to study and characterize the key dynamics that rule the gas giant satellite systems using an improved gravity field of the central body, estimated using radio tracking data of deep space probes. To accomplish our objective, we performed the data analysis of the previously mentioned deep space missions: Cassini, Juno and Galileo. Being the three probes the very first orbiters of gas giant planets, they provided, and still provide, precious information which contributes to unveil the gas giant satellite systems dynamics, their origin and evolution.