Electric Propulsion Interplanetary Missions using Libration Points: Development of analytic approaches and mission design

In this dissertation, the advantageous combination of Dynamical Systems Theory of three-body models with Electric Propulsion to design novel spacecraft interplanetary missions in multi-body regimes has been investigated. Particular attention has been focused on interplanetary transfers towards outer planets that are intrinsically associated with long transfer times and high DV budgets, especially if a final planetary capture is desired. A reference mission using Electric Propulsion in the three-body model has been selected in which, after the interplanetary phase, a planetary tour of the Uranian system orbiting consecutively Oberon, Titania, Umbriel, Ariel and Miranda has been designed. Application of low-thrust propulsion with its advantages with respect to propellant requirements has been used to interconnect ballistic trajectories on invariant manifolds associated with multiple three body systems. This has implied the necessity to investigate both in the field of the Dynamical Systems Theory applied to the Circular Restricted Three-Body problem and in the field of optimal control theory as optimization schemes have been necessary to design low-thrust arcs subjected to boundary constraints. Both the interplanetary trajectory and the planetary tour have been computed in different three-body environments, where the start of the interplanetary phase has been assisted by a high energy launch to limit the transfer time. Based on the reference mission, a preliminary spacecraft configuration has been developed in which Radioisotope Thermoelectric Generators have been considered to provide the necessary power source.