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Proceedings Paper

Global alignment optimization strategies, procedures, and tools for the James Webb Space Telescope (JWST) Integrated Science Instrument Module (ISIM)
Author(s): Brent J. Bos; Joseph M. Howard; Philip J. Young; Renee Gracey; Lenward T. Seals; Raymond G. Ohl
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Paper Abstract

During cryogenic vacuum testing of the James Webb Space Telescope (JWST) Integrated Science Instrument Module (ISIM), the global alignment of the ISIM with respect to the designed interface of the JWST optical telescope element (OTE) will be measured through a series of optical characterization tests. These tests will determine the locations and orientations of the JWST science instrument projected focal surfaces and entrance pupils with respect to their corresponding OTE optical interfaces. Thermal, finite element and optical modeling will then be used to predict the on-orbit optical performance of the observatory. If any optical performance non-compliances are identified, the ISIM will be adjusted to improve its performance. If this becomes necessary, ISIM has a variety of adjustments that can be made. The lengths of the six kinematic mount struts that attach the ISIM to the OTE can be modified and five science instrument focus positions and two pupil positions can be individually adjusted as well. In order to understand how to manipulate the ISIM’s degrees of freedom properly and to prepare for the ISIM flight model testing, we have completed a series of optical-mechanical analyses to develop and identify the best approaches for bringing a non-compliant ISIM Element back into compliance. During this work several unknown misalignment scenarios were produced and the simulated optical performance metrics were input into various mathematical modeling and optimization tools to determine how the ISIM degrees of freedom should be adjusted to provide the best overall optical performance.

Paper Details

Date Published: 21 September 2012
PDF: 12 pages
Proc. SPIE 8442, Space Telescopes and Instrumentation 2012: Optical, Infrared, and Millimeter Wave, 84423I (21 September 2012); doi: 10.1117/12.926365
Show Author Affiliations
Brent J. Bos, NASA Goddard Space Flight Ctr. (United States)
Joseph M. Howard, NASA Goddard Space Flight Ctr. (United States)
Philip J. Young, Young Engineering Services (United States)
Renee Gracey, Ball Aerospace & Technologies Corp. (United States)
Lenward T. Seals, NASA Goddard Space Flight Ctr. (United States)
Raymond G. Ohl, NASA Goddard Space Flight Ctr. (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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