Autonomous Navigation System for Spacecraft Using Low-Thrust Trajectories

This research describes a prototype software navigation system that would allow a spacecraft with a small amount of continuous propulsion to navigate low-energy trajectories. First, the desired route is described in terms of basic orbit shapes, such as Lyapunov orbits. This sequence of orbit shapes is converted into an itinerary of spatial boundaries that a spacecraft executing the low-energy maneuver will cross in order.A software system then employs a guided optimization algorithm that identifies the thrust angle that will maintain the desired orbit. Using this software as a research tool, simulations have identified low-energy paths that could be used by a spacecraft with an ion drive to perform a Venus flyby within four or five years of its launch from Earth. This approach makes it possible to identify complex low-energy trajectories that rely on the gravitational effects of different two-body systems (for instance, Earth–moon and Earth–sun) and to study the utility of continuous propulsion in flying such trajectories from Earth