Electric Propulsion and Spacecraft Trajectory Design

Application of electric propulsion as option for planetary and interplanetary orbit transfers is accompanied with trajectory design implication arising from the intrinsic characteristics of the produced low thrust. It is inevitable necessary to invoke some form of numerical integration in order to either compute or optimize the trajectory. The topic of electric propulsion application is expanded in this thesis with an outline of the associated trajectory design complications. The development of a numerical tool is discussed, where this tool is developed in order to collect the methods and techniques required for numerical trajectory analysis. The development is initiated in collaboration with the European Space Agency in order to ll a gap in availability of dedicated electric propulsion mission analysis tools. With the scope to demonstrate the eectiveness and possibilities of novel and intelligent application of electric propulsion two trajectory design studies are discussed. The feasibility to apply electric propulsion as the fundamental technology to design small-spacecraft missions capable of the exploration of the outer planets is demonstrated. Realistic mass and time budgets are considered with missions that provide high scientic outcomes. It will be shown that the high V budget associated with outer planet missions can be e- ciently fullled by electric propulsion, maintaining acceptable total mission durations and spacecraft nal mass. It is moreover demonstrated that the consideration of dynamical systems theory applied to three-body models in order to design low energy missions can benet from electric propulsion employment. Electric propulsion is capable to provide a precise low-thrust which can be used to connect the stable and instable low energy manifolds in dierent three-body models in order to design novel spacecraft trajectories. It will be shown that the stable and instable invariant manifolds associated with periodic orbits around the libration points of several Uranus - moon three-body systems can be connected by a small spacecraft with electric propulsion, in order to develop a complete planetary tour orbiting ve moons before reaching a stable orbit around Uranus.