Gamma guidance of trajectories for coplanar, aeroassisted orbital transfer
Abstract
This paper is concerned with the optimization and guidance of trajectories for coplanar, aeroassisted orbital transfer from high earth orbit to low earth orbit. Optimal trajectories are computed by minimizing the total velocity impulse for orbital transfer. They include two branches: a relatively short descending flight branch (branch 1) and a long ascending flight branch (branch 2). Nearoptimal guidance trajectories are implemented via a feedback control scheme in which the lift coefficient is adjusted according to a twostage gamma guidance law. For branch 1, the gamma guidance is a linear path inclination guidance; for branch 2, the gamma guidance is a constant path inclination guidance. A modified gamma guidance is developed; it differs from the gamma guidance in two aspects: lower target altitude and use of a predictorcorrector algorithm to determine the switch velocity and the target path inclination. The modified gamma guidance is quite stable with respect to dispersion effects arising from navigation errors, variations of the atmospheric density, and uncertainties in the aerodynamic coefficients.
 Publication:

Journal of Guidance Control Dynamics
 Pub Date:
 February 1992
 DOI:
 10.2514/3.20826
 Bibcode:
 1992JGCD...15..255M
 Keywords:

 Aeroassist;
 Control Theory;
 Earth Orbital Environments;
 Trajectory Control;
 Trajectory Optimization;
 Transfer Orbits;
 Atmospheric Entry;
 Feedback Control;
 Flight Control;
 Lift;
 Astrodynamics