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Proceedings Paper

Long-baseline optical interferometry in earth orbit: system comparisons
Author(s): Anthony B. DeCou
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Paper Abstract

This paper describes the orbital dynamics characteristics of three strategies for performing multi -kilometer optic al interferometry on astronomical sources in earth orbit, and compares the three •strategies from several points of view, which relate usable data to system costs. The three strategies that are thought to be the most likely to succeed are: 1, the "Hanging Tether" approach in which two collectors are suspended at the ends of a gravity gradient stabilized tether with the central station located on an elevator that moves up and down the tether to keep the optical path lengths equal; 2, the "Free Flyer" approach in which the two collectors and the central station are independent satellites in stationkeeping mode; and 3, the "Spinning Tether" approach in which three collectors are located at the corners of an equilateral tnangle connected by three tethers and rotating about their common center of mass. In each case it is assumed that data is recorded as the baselines continuously traverse the U-v plane in either elliptical or circular paths. It is determined on the basis of previous work in each case that continuous thrusting which is small enough to be provided by ion thrusters is the best method of compensating for gravity gradient disturbances. The fuel requirements for these thrusters is determined for the three cases and compared, based on the assumption of uniform fringe sampling density in the U-V plane. The main conclusion is that all of the systems are feasible in synchronous orbit, but questionable in low earth orbit. Experimental data on the interactions between optical systems, ion thrusters, and tether vibrations is needed before a final choice can be made.

Paper Details

Date Published: 1 August 1990
PDF: 13 pages
Proc. SPIE 1237, Amplitude and Intensity Spatial Interferometry, (1 August 1990); doi: 10.1117/12.19341
Show Author Affiliations
Anthony B. DeCou, Northern Arizona Univ. and Jet Propulsion Lab. (United States)


Published in SPIE Proceedings Vol. 1237:
Amplitude and Intensity Spatial Interferometry
James B. Breckinridge, Editor(s)

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