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Proceedings Paper

Primary mirror shape control for athermalization using embedded sensors
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Paper Abstract

The next generation of space telescopes will be required to meet very challenging science goals. In order to achieve these goals, the size of the primary mirror will need to be increased. However, since current telescopes are reaching their limits in terms of size and mass, new designs will require advanced technologies such as lightweight mirrors and active optical control. Traditional shape control of the primary mirror relies on feedback from a wavefront sensor located in the optical path. However, a wavefront sensor reduces the amount of light available for image formation. Therefore, to view very dim objects, it will be necessary to use a different type of sensor. In this work, a quasi-static shape control algorithm is developed to correct errors in the mirror due to thermal disturbances using only sensors embedded in the mirror. Control algorithms are presented for both embedded strain gages and temperature sensors. Finite element models of both a simple flat plate mirror and a rib-stiffened mirror are generated and analyzed using Nastran. The flat plate model, with surface-parallel actuation is used to compare the two algorithms. Following this, the parametric model for a rib-stiffened mirror is used to analyze the effects of the shape control algorithm as the mirror geometry is changed. It is shown that correction of a mirror can be achieved using these embedded sensors.

Paper Details

Date Published: 20 September 2007
PDF: 12 pages
Proc. SPIE 6687, UV/Optical/IR Space Telescopes: Innovative Technologies and Concepts III, 66870W (20 September 2007); doi: 10.1117/12.736852
Show Author Affiliations
Elizabeth Jordan, MIT Space Systems Lab. (United States)
David W. Miller, MIT Space Systems Lab. (United States)

Published in SPIE Proceedings Vol. 6687:
UV/Optical/IR Space Telescopes: Innovative Technologies and Concepts III
Howard A. MacEwen; James B. Breckinridge, Editor(s)

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