Surrogate-based entire trajectory optimization for full space mission from launch to reentry

Abstract

A surrogate-based optimization method is proposed in this paper to realize the optimization of the entire trajectory from launch to reentry. Different from traditional strategy of multiphase trajectory optimization that directly utilizes the original dynamical model, a surrogate model is substituted for the original time-consuming model to improve the iterative efficiency and decrease the computational cost. The procedures of modeling, solving, and optimizing in each substage are addressed, including air-launch ascent trajectory optimization, orbital maneuver planning, deorbit braking, and atmospheric reentry. Instead of optimizing every substage separately and setting interfaces by experience, in this study, substages are patched as an entire system in advance and then the surrogate model is utilized to replace it to perform a systematic optimization. Additionally, the Fourier series is applied to fit the air launch stage during the iteration. Numerical simulations show that the proposed method is acceptable for the pre-design of a full space mission and the results are optimal.