LOW-THRUST VEHICLE GUIDANCE STUDY: VOLUME II, PARTS II AND III.

Abstract : This report considers various aspects of the guidance of a low-thrust vehicle. The report is divided into three parts: theory, guidance system implementation, and space sextant feasibility demonstration. The first part on theory presents a guidance scheme suitable for use on an arc-jet vehicle in an earth to lunar orbiting mission. Numerical results are presented which demonstrate the capability and performance of this scheme. The second part presents implementation schemes for a self-contained guidance and attitude control system for a lunar reconnaissance mission. The system uses a precise automatic space sextant supported by two mechanical degrees-of-freedom as a primary source of guidance and attitude control information. The third part reports on a laboratory experimental program to demonstrate the feasibility of the space sextant. Included are a physical description of the instrument and complete error analysis. (Author)