FEASIBILITY TEST FOR A V-SLIT STAR MAPPER FOR PIONEER SPACECRAFT TERMINAL NAVIGATION Final Report

摘要

A laboratory demonstration of the feasibility of using a V-slit star mapper to meet the sensitivity and accuracy of on-board naviga¬tional requirements for future Pioneer Missions to the outer planets has been conducted by the Control and Sensors Laboratory of TRW.nThe V-slit star mapper breadboard used in the laboratory tests was made available from another program at TRW. Thus, the physical configuration was predetermined. In like manner, the mechanical test set used in testing the sensor was made available to the project, by the Pioneer-Jupiter program at TRW on a no conflict basis.nThe first major thrust of the project was to determine ana¬lytically if the breadboard sensor could meet the performance required. The breadboard was extremely simple in configuration, consisting of an end-on photomultiplier tune and a V-slit reticle located at the focal plane of the objective lens. In addition, a plano-convex lens was used between the reticle and the PMT in a Fabry-Perot configuration. The analytical effort indicated that the sensor should easily meet the requirements and the second major effort began, This was to test the Pioneer SRA test set to determine its basic accuracy and modify it where necessary to bring its accuracy into the 1-3 arc second range. This proved to be a much lamer problem than expected. The rotating mirror spin rate stability became the critical factor. It was finally resolved by driving the synchronous motor with a high-fidelity power amplifier excited by a precision sine wave generator.