Control optimization of a lifting body entry problem by an improved and a modified method of perturbation functions

The present investigation is a study of the solution of a complex entry optimization problem. The problem is transformed into a two-point boundary value problem by using classical calculus of variations methods. Two-point boundary value problems usually require iterative numerical methods for solution, and thus, two perturbation methods were devised. These methods attempted to desensitize the contingency of the solution of this type of problem on the required initial co-state estimates. Numerical results are presented for the optimal solution resulting from a number of different initial co-state estimates. The perturbation methods are compared, and it is found that they are an improvement over existing methods.