The 1st John V. Breakwell Memorial Lecture: Recent advances in the optimization and guidance of aeroassisted orbital transfers

Abstract

Aeroassisted orbital transfer (AOT) combines space maneuvers and atmospheric maneuvers so as to achieve propellant savings vis-à-vis purely propulsive maneuvers, albeit at the expense of high heating rates during the atmospheric pass. Of critical importance is the study of optimal trajectories; equally important is the development of guidance schemes in view of the precision requirements of AOT trajectories and the need for coping with various sources of dispersion effects. In this lecture, optimal trajectories are reviewed with reference to angle of bank control. Trajectories are optimized: from the point of view of performance and control margin. Compromise trajectories are generated from a trade-off between performance and control margin. The ultimate goal is to arrive at practical AOT guidance trajectories exhibiting many of the desirable characteristics of AOT optimal trajectories. Guidance advances are reviewed with reference to angle of bank control, in particular, safety zone exit guidance and complete entry/exit guidance. Continuation of research efforts in the area of guidance is important, indeed essential, for the future development of AOT vehicles. In particular, the use of parallel computation for real-time guidance is worthy of investigation.