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Proceedings Paper

James Webb Space Telescope first light boresight to spacecraft alignment determination
Author(s): Paul A. Lightsey; D. Scott Acton; J. Scott Knight; Adam Contos
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Paper Abstract

The James Webb Space Telescope is a large deployable cryogenic space telescope that is pointed on the sky by control of the attitude of the integrated spacecraft and telescope. The primary mirror has 18 hexagonal Primary Mirror Segment Assemblies (PMSA) that are deployed; 3 on each of two deployable wings, and 12 on a fixed central section of the Primary Mirror Backplane Support Structure. The Secondary Mirror (SM) is deployed from the Secondary Support Structure that folds out from the backplane, and the complete Telescope and Integrated Science Instrument Module are deployed in extension from the spacecraft. The resulting tolerances will result in a "first light" image that has a spread array of 18 individual images for each point source located within the field of view. The initial attitude of the spacecraft will be adjusted to point the telescope to a desired star field for the initial WFSC commissioning process. The deployment tolerances will result in the telescope field of view being offset from the desired location. By use of a sequence of pointings, a mosaic "first light" image that includes the multiplicity of the 18 misaligned segment images may be created that will allow the calibration of the offset between the telescope boresight and the spacecraft attitude control system, allowing subsequent pointing to be done accurately to a fraction of the field of view of the instruments using spacecraft attitude control.

Paper Details

Date Published: 21 September 2012
PDF: 7 pages
Proc. SPIE 8442, Space Telescopes and Instrumentation 2012: Optical, Infrared, and Millimeter Wave, 84423H (21 September 2012); doi: 10.1117/12.926123
Show Author Affiliations
Paul A. Lightsey, Ball Aerospace & Technologies Corp. (United States)
D. Scott Acton, Ball Aerospace & Technologies Corp. (United States)
J. Scott Knight, Ball Aerospace & Technologies Corp. (United States)
Adam Contos, Ball Aerospace & Technologies Corp. (United States)

Published in SPIE Proceedings Vol. 8442:
Space Telescopes and Instrumentation 2012: Optical, Infrared, and Millimeter Wave
Mark C. Clampin; Giovanni G. Fazio; Howard A. MacEwen; Jacobus M. Oschmann Jr., Editor(s)

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