Optimal descending, hypersonic turn to heading

Approximations are made to the point-mass equations of motion for flight within the atmosphere. Optimal controls are formulated for a reentry vehicle to execute a maximum-terminal-velocity turn to a specified heading while executing steep, descent trajectories. A Newton scheme is used repetitively to solve a nonlinear algebraic system for two parameters in the control equations to provide the on-line guidance. Trajectory comparisons from the repetitive solution of the optimal control problem, pure numerical optimization, and simulation of sample-data guidance show good agreement, if the atmospheric model is accurate.