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Proceedings Paper

Kilometer scale telescope collector deployable in a shuttle payload
Author(s): Thomas D. Ditto
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Paper Abstract

We propose a space telescope that has a diffraction grating as its primary objective element. A membrane grating in the shape of a ribbon could enjoy aperture length above a kilometer. This novel configuration would be particularly useful for very high resolution spectrographic astronomy as required in Doppler shift searches for extra-solar planets due to its very wide aperture in the one dimension used for dispersion and its unprecedented spectral resolving power. Rolls can be stowed in the payload bay for Shuttle delivery into orbit, then unfurled and kept flat using inertial guidance from gyroscopes and centrifugal forces. The large primary collector would not require formation flying since the membrane would provide a mechanical tether. We suggest experiments to establish feasibility of the deployment. We also suggest studies for the tensile mechanics and environmental stresses on the device. Our analysis investigates the parameters of surface flatness, membrane thickness, metallic coating conductivity, grating period, groove blaze and depth. We analyze options for fabrication such as roll embossing of multiple-kilometer length membrane substrates. We also consider an evanescent mode grating in a transmission medium which can be formed using methods now commonplace in telecommunication fiber optics.

Paper Details

Date Published: 9 December 2004
PDF: 12 pages
Proc. SPIE 5578, Photonics North 2004: Photonic Applications in Astronomy, Biomedicine, Imaging, Materials Processing, and Education, (9 December 2004); doi: 10.1117/12.606728
Show Author Affiliations
Thomas D. Ditto, DeWitt Brothers Tool Co., Inc. (United States)

Published in SPIE Proceedings Vol. 5578:
Photonics North 2004: Photonic Applications in Astronomy, Biomedicine, Imaging, Materials Processing, and Education
Marc Nantel; Glen Herriot; Graham H. McKinnon; Leonard MacEachern; Robert A. Weersink; Rejean Munger; Andrew Ridsdale, Editor(s)

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