Hybrid Genetic Algorithm Gauss Pseudospectral Method for the Electric Sail Trajectory Optimization

The electric sail is an innovative propulsion concept which uses the solar wind dynamic pressure to produce a thrust without the need for reaction mass. The electric sail is consisted by many tethers which are connected to a solar-powered electron gun. The electron gun emits electrons to maintain the tethers at a high positive potential. The electric field generated by the tethers reflects the solar wind ions to generate a thrust. In this paper, a hybrid genetic algorithm Gauss pseudospectral method is proposed to optimize the trajectory of the electric sail. The initial guesses for the state and control histories used in the Gauss pseudospectral method are interpolated from the best solution of a genetic algorithm. The proposed hybrid approach effectively includes global search ability of genetic algorithm and the high convergence rate of sequential quadratic programming. The numerical results show that the hybrid optimization method has the capability to search the feasible and global optimal solution of the electric sail trajectory without any initial value guess.