Accession Number : ADA019328

Title :   Time-Optimal Rendezvous for an Upper Stage Vehicle of the Space Transportation System.

Descriptive Note : Master's thesis,

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

Personal Author(s) : Johnson,Raymond P.

Report Date : DEC 1975

Pagination or Media Count : 145

Abstract : This study investigates minimum-time rendezvous trajectories and thrust control profiles for an upper stage vehicle of the Space Transportation System. A numerical technique is presented to solve the nonlinear two-point boundary value problem associated with the finite-thrust time-optimal trajectories. This method serves to reduce the associated computer burden through the use of a general-purpose subroutine developed by the mathematician M.J.D. Powell to solve a system of nonlinear equations. The general technque uses a gradient-type iteration when poorer estimates of the unknowns are encountered and, yet, switches automatically to the more rapid convergence of a Newton-Raphson scheme as the estimates are improved. The discontinuities associated with the on-off thrust control are overcome through an iterative determination of the related switching times.

Descriptors :   *Space shuttles, *Rendezvous trajectories, Reusable equipment, Space tugs, Space transportation, Transfer trajectories, Boundary value problems, FORTRAN, Computer programs, Theses, Nonlinear differential equations, Calculus of variations, Numerical integration

Subject Categories : Unmanned Spacecraft
      Spacecraft Trajectories and Reentry

Distribution Statement : APPROVED FOR PUBLIC RELEASE