Preliminary design of low-thrust transfer trajectory with planetary swing-bys

A method for designing interplanetary low-thrust trajectory with planetary swing-bys is proposed based on shape-based theory. In this method, the modified inverse polynomial is used to approximately calculate low-thrust arcs. The B-plane parameters and switching time parameters are introduced to achieve the patch of planetary swing-bys and thrust-coast hybrid trajectories. The preliminary design problem can be transformed into solving a mixed-integer nonlinear programming problem (MINLP). In order to obtain optimal design parameters, the design model is simplified by parameter transformation, and a modified differential evolution algorithm is used to solve the MINLP. Numerical simulations demonstrate that, compared with the exponential sinusoid method, the proposed approach can be used to design transfer trajectories for rendezvous missions, and also to realize exploration opportunities with less fuel.