Multi-objective trajectory optimization for a hybrid propulsion system

It is attractive to use a hybrid propulsion system (HPS) consisting of solar electric propulsion (SEP) and solar radiation pressure (SRP) in interplanetary and near-Earth missions. Compared with the equivalent pure sail and pure SEP trajectories, HPS can reduce fuel consumption and transfer time. A multi-objective optimization model for the three-dimensional rendezvous mission of hybrid propulsion system is established in this paper. The optimization index is defined as a weighted sum of transfer time and the fuel consumption. Solutions with the bang-bang thrust profile are obtained under the specific mission constraints of time and fuel consumption. The influence of weights on the optimization results is discussed, and a reasonable weight range is given based on the magnitude analysis. By combining the homotopy approach with time-optimal solar sail trajectory, the initial value of the covariates are well estimated. Numerical simulations are performed both on Earth-2000SG344 and Earth-Apophis rendezvous. The results indicate that the proposed method is advantageous to obtain solutions with different mission time and fuel consumption flexibility.