Preliminary Analysis of Low-Thrust Gravity Assist Trajectories by An Inverse Method and a Global Optimization Technique

The design of interplanetary trajectories requires the solution of an optimization problem typically requiring a first guess solution. In addition the most recent development in low-thrust propulsion open the doors to new perspectives for the exploration of the solar system, while at the same time increasing the difficulties related to the trajectory design process. In this paper an automatic method for the preliminary definition of complex interplanetary transfer characterized by multiple swing by, either low-thrust or impulsive maneuvers is presented. The goal is achieved combining a novel methodology for the description of low-thrust arcs, based on an inverse method, with a global optimization algorithm based on an hybridization of an evolutionary search with a deterministic branching step. This approach allows a broad investigation of the solution domain as it is required in a preliminary design phases, where the availability a large number of first guess solutions is important.