Spacecraft reentry trajectory optimization by heuristic optimization methods and optimal control theory

In the present work, a hybrid method for trajectory optimization of reentry spacecraft was proposed. The guiding legislation on the basis of heat reduction is presented in the procedure of obtaining the optimal trajectory. The heat rate should be decreased in the early phase of reentry flight by concentrating on the angle of attack profile. To meet terminal circumstances, the second step of suggested guidance included specifying the accurate profiles of the angle of attack and bank angle. A specific cost function should be minimized in each step. As a result, many optimization strategies have been utilized and compared. Due to its long flight duration and numerical sensitivity, the optimum trajectory issue of the space reentry vehicle (SRV) has been explored as one of the toughest problems in trajectory design. In both phases, the ideal trajectory for the optimality requirements has been discovered for various cost functions such as (i) overall heat rate, (ii) maximal heat rate, and (iii) terminal conditions. It may be inferred that the unique suggested strategy can minimize heat while maintaining the final conditions.