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Proceedings Paper

Optical transmission for the James Webb Space Telescope
Author(s): Paul A. Lightsey; Benjamin B. Gallagher; Neal Nickles; Tracy Copp
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Paper Abstract

The fabrication and coating of the mirrors for the James Webb Space Telescope has been completed. The spectral reflectivity of the protected gold coated beryllium mirrors has been measured. The predicted end-of-life transmission through the telescope builds from these values. The additional phenomena that have been analyzed are contamination effects and effects of the environment for the JWST operation about the Earth-Sun L2 Lagrange libration point. The L2 environment analysis has been based on radiation testing of mirror samples and hypervelocity testing to assess the micrometeoroid impact effects. The mirror showed no change in reflectance over the VIS-SWIR wavelengths after exposure to 6-9 Grad (Si) that simulated 6 years orbiting the L2 Lagrange point. The effects of hypervelocity particle impacts on the mirrors from test data has been extrapolated to the to the anticipated flux characteristics for micrometeoroids at the L2 environment. The results show that the micrometeoroid effects are orders of magnitude below the particulate contamination effects. The final end-of-life transmission for the mirrors including all of these phenomena will meet the performance requirements for JWST.

Paper Details

Date Published: 21 September 2012
PDF: 9 pages
Proc. SPIE 8442, Space Telescopes and Instrumentation 2012: Optical, Infrared, and Millimeter Wave, 84423A (21 September 2012); doi: 10.1117/12.924841
Show Author Affiliations
Paul A. Lightsey, Ball Aerospace & Technologies Corp. (United States)
Benjamin B. Gallagher, Ball Aerospace & Technologies Corp. (United States)
Neal Nickles, Ball Aerospace & Technologies Corp. (United States)
Tracy Copp, 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, Editor(s)

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