CONTROL STRATEGIES FOR SPACE BOOSTERS USING AIR COLLECTION SYSTEMS

A simple and efficient performance analysis method is developed for ev aluating vehicle pitch and engine throttle controls to minimize booste r fuel required to rill second-stage liquid oxygen (LOX) tanks and del iver the vehicle to the staging point. An optimization methodology fin ds a throttle schedule that controls both the air-breathing engine and the LOX collection rate. The altitude-velocity profile is derived fro m a variational calculus/energy management contouring method. Automati c adaptive-gain pitch-rate and throttle controls are developed. Result s from a parametric study show that collecting on the run for an optim um schedule results in a 17% fuel savings over collection at a constan t Mach number.