Maximizing the Semi-Major Axis for a Freely Coning Solar Sailcraft.
Abstract
This thesis addresses the maximation of the circular orbit radius of an earth-orbiting solar sail under free coning motion. The objective is to find the optimal sail settings producing the most change in the semi-major axis per orbit. Angular orientations with respect to sail nutation, precession, mean motion, and its angular momentum control the magnitude of the solar thrust along the sailcraft's velocity direction. A numerical search scheme uses a modified Newton-Rapson iteration method to identify sets of control parameters meeting certain optimality conditions that produce a stationary value in a selected performance index. Such a scheme displays its vulnerability to a lack of a good initial guess. Three dimensional perspectives of the small perturbation equation describing the behavior of the change in semi-major axis facilitates the understanding of its cyclic nature and provides an excellent tool for identifying the various locations of possible maxima (and minima) as well as slope-critical area. The perspectives improves the initial guess for implementing maxima search schemes. A test case demonstrates the location of particular points of interest with few search iterations. Keywords; Orbital perturbations, Coning motions, and Computer programs and Optimization.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1984
- Accession Number
- ADA153175
Entities
People
- M. R. Borja
Organizations
- Air Force Institute of Technology