AAS 97-656
STABILITY ANALYSIS OF OPTIMAL THREE-DIMENSIONAL HYPERSONIC SKIP TRAJECTORIES
L. de-Olive' Ferreira and A.F.B.A. Prado, INPE - Natl. Inst. for Space Research, Brazil; N.X. Vinh, University of Michigan, Michigan.
Abstract
An analytical theory for the highly unsteady, strongly nonlinear, geometrically complex problem of stability of optimal three-dimensional, non-thrusting, single-pass skip maneuvers is introduced. Under Eggers's classical hypothesis, and assuming a shallow entry, we start out by solving a final-speed maximization problem. This yields explicit optimal control laws. The resulting trajectory is then adopted as a reference to which regular perturbations are applied, with the corresponding equations being subsequently nondimensionalized. Analysis of the system thus obtained reveals that existence of a new mode typical of hypersonic, high-altitude flight can be expected. Stability of this mode is assessed and a set of accurate analytic solutions for three-dimensional skips is presented.