USING SPARSE NONLINEAR-PROGRAMMING TO COMPUTE LOW THRUST ORBIT TRANSFERS

One of the most effective numerical techniques for the solution of tra jectory optimization and optimal control problems is the direct transc ription method. This approach combines a sparse nonlinear programming algorithm with a discretization of the trajectory dynamics. This paper describes the application of a sparse nonlinear programming method to the solution of a low thrust orbit transfer. The vehicle dynamics are defined using equinoctial coordinates, and solutions are presented fo r transfers which require large changes in the orientation of the orbi t plane. The resulting problem involves 4352 variables, and 868 degree s of freedom, with over 3484 very nonlinear constraints.