Design and Feasibility Assessment of Ultra Low Thrust Trajectories to the Sun-Earth Saddle Point

In this paper methods and concepts are presented to design and validate highly nonlinear orbits characterized by ultra low control authority. These features are met when flying through the Saddle Points, which are locations in the Solar System where net gravitational accelerations balance. Trajectory optimization is performed into high-fidelity environments, where accurate description of the spacecraft natural and controlled motion is achieved. To assess feasibility, orbit determination and covariance analysis are simulated by modeling both the space and ground segments. Methods and tools have been developed and applied to the case of the possible mission extension of Lisa PathFinder.