Improvement of Jupiter's satellites ephemerides using stellar occultation observations

The inner Galilean moons orbiting Jupiter are locked into the so-called “Laplace resonance”, where the orbital periods of Ganymede, Europa and Io maintain a 4:2:1 ratio respectively. Resonant dynamics appear several times across the Solar System and determining whether the Jovian resonance is deepening or loosening would provide a direct insight into the origin and the evolution of the Solar System. At the moment, our knowledge of the Galilean moons' dynamics is not accurate enough to establish in which direction the system is evolving. Including stellar occultation observations obtained from an orbiting spacecraft could result in a critical improvement of these estimations. Since the spacecraft’s orbit and the stars’ position are generally very well known, every time one of the moons crosses the line-of-sight from the spacecraft to the star its position can be constrained very accurately. The results of this thesis lay the foundations for the introduction of stellar occultation observations in the orbit determination process of planetary satellites and other celestial bodies. First, a geometrical/mathematical model of the distance between the moon’s limbs and a given star detected in its surroundings was developed and tested. Afterwards, a code to detect and archive all the stellar occultation events in a given time span was implemented. Finally, a parametric covariance analysis was performed to obtain a preliminary assessment of the improvements provided by the introduction of stellar occultation observations and investigate the influence of each variable on the orbit determination problem.