Thermal Protection System Weight Minimization for the Space Shuttle through Trajectory Optimization

This paper discusses the results of employing a first-order optimization algorithm to the problem of minimizing the weight of the re-entry thermal protection system (TPS) for the space shuttle. Mathematical models of two types of thermal protection systems are derived, a metallic TPS and a reusable surface insulation (RSI) TPS. Optimal entries were generated using maximum orbiter nose temperature as a parameter. Thermal protection system weights were computed for both fixed and variable angles of attack using three-dimensional entry trajectories. Results indicated that variable angle-of-attack entries require less thermal protection system weight than entries at a constant angle of attack (35°) for both systems considered.