Earth-Mars low-thrust trajectory design based on hybrid method

The fuel-optimal low-thrust transfer with constant thrust utilizing hybrid method is investigated. Hybrid method combines Pontragin maximum principle with sequential quadratic programming, but the transversality conditions are not considered. Therefore the nonlinear two-point boundary value problem is avoided to solve and the convergence of iteration is improved greatly. An example of constant magnitude low-thrust Earth-Mars orbit transfer is presented in order to demonstrate the approach of hybrid method. The numerical results show that the computing speed is fast and the time history of states and costates is continuous and smooth. Hybrid method is effective in the design of low-thrust interplanetary orbit transfer.