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Proceedings Paper

Cryogenic pupil alignment test architecture for the James Webb Space Telescope integrated science instrument module
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Paper Abstract

The James Webb Space Telescope (JWST) is a space-based, infrared observatory designed to study the early stages of galaxy formation in the Universe. It is currently scheduled to be launched in 2013 and will go into orbit about the second Lagrange point of the Sun-Earth system and passively cooled to 30-50 K to enable astronomical observations from 0.6 to 28 μm. The JWST observatory consists of three primary elements: the spacecraft, the optical telescope element (OTE) and the integrated science instrument module (ISIM). The ISIM Element primarily consists of a mechanical metering structure, three science instruments and a fine guidance sensor with significant scientific capability. One of the critical opto-mechanical alignments for mission success is the co-registration of the OTE exit pupil with the entrance pupils of the ISIM instruments. To verify that the ISIM Element will be properly aligned with the nominal OTE exit pupil when the two elements come together, we have developed a cryogenic pupil measurement test architecture to measure three of the most critical pupil degrees-of-freedom during optical testing of the ISIM Element. The pupil measurement scheme makes use of: specularly reflective pupil alignment references located inside of the JWST instruments; ground support equipment that contains a pupil imaging module; an OTE simulator; and pupil viewing channels in two of the JWST flight instruments. Current modeling and analysis activities indicate this measurement approach will be able to verify pupil shear to an accuracy of 0.5-1%.

Paper Details

Date Published: 12 July 2008
PDF: 12 pages
Proc. SPIE 7010, Space Telescopes and Instrumentation 2008: Optical, Infrared, and Millimeter, 70103C (12 July 2008); doi: 10.1117/12.789808
Show Author Affiliations
Brent J. Bos, NASA Goddard Space Flight Ctr. (United States)
David A. Kubalak, NASA Goddard Space Flight Ctr. (United States)
Scott R. Antonille, NASA Goddard Space Flight Ctr. (United States)
Raymond G. Ohl, NASA Goddard Space Flight Ctr. (United States)
John G. Hagopian, NASA Goddard Space Flight Ctr. (United States)
Pamela S. Davila, NASA Goddard Space Flight Ctr. (United States)
Joseph Sullivan, Ball Aerospace and Technologies Corp. (United States)
Michael Sánchez, Ball Aerospace and Technologies Corp. (United States)
Derek Sabatke, Ball Aerospace and Technologies Corp. (United States)
Robert A. Woodruff, Lockheed Martin Space Systems Co. (United States)
Maurice te Plate, ESA European Space Research and Technology Ctr. (Netherlands)
Clinton Evans, COM DEV (Canada)
Victor Isbrucker, Isbrucker Consulting (Canada)
Stephen Somerstein, Lockheed Martin Advanced Technology Ctr. (United States)
Martyn Wells, UK Astronomy Technology Ctr., Royal Observatory (United Kingdom)
Samuel Ronayette, CEA Saclay (France)


Published in SPIE Proceedings Vol. 7010:
Space Telescopes and Instrumentation 2008: Optical, Infrared, and Millimeter
Jacobus M. Oschmann; Mattheus W. M. de Graauw; Howard A. MacEwen, Editor(s)

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