Lift modulation for maximum endurance planetary entry
Abstract
Optimal lift modulation for maximum endurance planetary entry trajectories of Shuttle type vehicles is investigated. The force field of the planet is considered Newtonian, and the atmosphere is assumed to be exponential. Motion is confined to the plane of a great circle to obtain maximum endurance, and a set of dimensionless variables and a normalized lift coefficient are used to obtain an overview of the optimal trajectories. The variational problem is reduced to a twoparameter function, and maximum endurance trajectories for a Shuttle reentering the earth atmosphere are derived by integrating the dimensionless state equation with a certain specified initial state. The optimal lift control is also formulated for maximum endurance gliding trajectories of fighter type vehicles at low altitudes and speed, and tends to the value of the steady state solution, the square root of three.
 Publication:

Rome International Astronautical Federation Congress
 Pub Date:
 September 1981
 Bibcode:
 1981rome.iafcR....Y
 Keywords:

 Atmospheric Entry;
 Lift;
 Planetary Atmospheres;
 Reentry Trajectories;
 Time Optimal Control;
 Trajectory Optimization;
 Equations Of Motion;
 Equations Of State;
 Glide Paths;
 Space Shuttles;
 Variational Principles;
 Astrodynamics