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Proceedings Paper

Optical metrology and alignment of the James Webb Space Telescope Integrated Science Instrument Module
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Paper Abstract

The James Webb Space Telescope (JWST) is an infrared space telescope scheduled for launch in 2013. JWST has a 6.5 meter diameter deployable and segmented primary mirror, a deployable secondary mirror, and a deployable sun-shade. The optical train of JWST consists of the Optical Telescope Element (OTE), and the Integrated Science Instrument Module (ISIM), which contains four science instruments. When the four science instruments are integrated to ISIM at NASA Goddard Space Flight Center, the structure becomes the ISIM Element. The ISIM Element is assembled at ambient cleanroom conditions using theodolite, photogrammetry, and laser tracker metrology, but it operates at cryogenic temperature, and temperature-induced mechanical and alignment changes are measured using photogrammetry. The OTE simulator (OSIM) is a high-fidelity, cryogenic, telescope simulator that features a ~1.5 meter diameter powered mirror. OSIM is used to test the optical performance of the science instruments in the ISIM Element, including focus, pupil shear, and wavefront error. OSIM is aligned to the flight coordinate system in six degrees of freedom via OSIM-internal cryogenic mechanisms and feedback from alignment sensors. We highlight optical metrology methods, introduce the ISIM and the Science Instruments, describe the ambient alignment and test plan, the cryogenic test plan, and verification of optical performance of the ISIM Element in cryo-vacuum environment.

Paper Details

Date Published: 2 September 2008
PDF: 10 pages
Proc. SPIE 7068, Optical System Alignment and Tolerancing II, 70680F (2 September 2008); doi: 10.1117/12.798778
Show Author Affiliations
Joseph A. Connelly, NASA Goddard Space Flight Ctr. (United States)
Brent J. Bos, NASA Goddard Space Flight Ctr. (United States)
Pamela S. Davila, NASA Goddard Space Flight Ctr. (United States)
William L. Eichhorn, NASA Goddard Space Flight Ctr. (United States)
Bradley J. Frey, NASA Goddard Space Flight Ctr. (United States)
John G. Hagopian, NASA Goddard Space Flight Ctr. (United States)
Jason E. Hylan, NASA Goddard Space Flight Ctr. (United States)
James M. Marsh, NASA Goddard Space Flight Ctr. (United States)
Douglas B. McGuffey, NASA Goddard Space Flight Ctr. (United States)
Joseph McMann, QinetiQ North America (United States)
Maria D. Nowak, NASA Goddard Space Flight Ctr. (United States)
Raymond G. Ohl, NASA Goddard Space Flight Ctr. (United States)
Kevin W. Redman, QinetiQ North America (United States)
Derek Sabatke, Ball Aerospace & Technologies Corp. (United States)
Henry P. Sampler, NASA Goddard Space Flight Ctr. (United States)
Joseph Stock, SGT, Inc. (United States)
Joseph Sullivan, Ball Aerospace & Technologies Corp. (United States)
Gregory W. Wenzel, QinetiQ North America (United States)
Geraldine A. Wright, NASA Goddard Space Flight Ctr. (United States)
Philip Young, Young Engineering Services (United States)


Published in SPIE Proceedings Vol. 7068:
Optical System Alignment and Tolerancing II
José M. Sasian; Richard Neil Youngworth, Editor(s)

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