Accession Number : AD0745998

Title :   A Comparison of the Gradient and Newton-Raphson Techniques for Reentry Trajectory Optimization.

Descriptive Note : Master's thesis,

Corporate Author : AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OHIO SCHOOL OF ENGINEERING

Personal Author(s) : Henson,William E. ; Robertson,Gerald A.

Report Date : JUN 1972

Pagination or Media Count : 172

Abstract : The report contains a two-dimensional optimization analysis of reentry trajectories for minimization of space vehicle heating and maximization of terminal range, conducted for a lifting body reentry vehicle with a maximum lift-to-drag of three. Based on this analysis there appears to be a conflict between heat minimization and range maximization in that a high angle-of-attack is required to minimize the heating rate and a lower angle-of-attack is required to maximize range. Two optimization techniques were compared, a Newton-Raphson method and a steepest-descent gradient method. A modification of the gradient technique, which was based upon the variational Hamiltonian, was applied after convergence to a near-optimal solution, resulting in an improved control profile. (Author)

Descriptors :   (*ATMOSPHERE ENTRY, OPTIMIZATION), (*LIFTING REENTRY VEHICLES, DESCENT TRAJECTORIES), LIFT, DRAG, ANGLE OF ATTACK, AERODYNAMIC HEATING, BOUNDARY VALUE PROBLEMS, MATHEMATICAL MODELS, MANNED SPACECRAFT, STEEPEST DESCENT METHOD, NUMERICAL METHODS AND PROCEDURES, THESES

Subject Categories : Spacecraft Trajectories and Reentry
      Manned Spacecraft

Distribution Statement : APPROVED FOR PUBLIC RELEASE