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Wavefront-Error Performance Characterization for the James Webb Space Telescope (JWST) Integrated Science Instrument Module (ISIM) Science InstrumentsThe science instruments (SIs) comprising the James Webb Space Telescope (JWST) Integrated Science Instrument Module (ISIM) were tested in three cryogenic-vacuum test campaigns in the NASA Goddard Space Flight Center (GSFC)'s Space Environment Simulator (SES). In this paper, we describe the results of optical wavefront-error performance characterization of the SIs. The wavefront error is determined using image-based wavefront sensing (also known as phase retrieval), and the primary data used by this process are focus sweeps, a series of images recorded by the instrument under test in its as-used configuration, in which the focal plane is systematically changed from one image to the next. High-precision determination of the wavefront error also requires several sources of secondary data, including 1) spectrum, apodization, and wavefront-error characterization of the optical ground-support equipment (OGSE) illumination module, called the OTE Simulator (OSIM), 2) plate scale measurements made using a Pseudo-Nonredundant Mask (PNRM), and 3) pupil geometry predictions as a function of SI and field point, which are complicated because of a tricontagon-shaped outer perimeter and small holes that appear in the exit pupil due to the way that different light sources are injected into the optical path by the OGSE. One set of wavefront-error tests, for the coronagraphic channel of the Near-Infrared Camera (NIRCam) Longwave instruments, was performed using data from transverse translation diversity sweeps instead of focus sweeps, in which a sub-aperture is translated andor rotated across the exit pupil of the system.Several optical-performance requirements that were verified during this ISIM-level testing are levied on the uncertainties of various wavefront-error-related quantities rather than on the wavefront errors themselves. This paper also describes the methodology, based on Monte Carlo simulations of the wavefront-sensing analysis of focus-sweep data, used to establish the uncertainties of the wavefront error maps.
Document ID
20160007981
Acquisition Source
Goddard Space Flight Center
Document Type
Presentation
Authors
Aronstein, David L.
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Smith, J. Scott
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Zielinski, Thomas P.
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Telfer, Randal
(Space Telescope Science Inst. Baltimore, MD, United States)
Tournois, Severine C.
(Sigma Space Corp. Lanham, MD, United States)
Moore, Dustin B.
(Rochester Univ. NY, United States)
Fienup, James R.
(Rochester Univ. NY, United States)
Date Acquired
June 28, 2016
Publication Date
June 26, 2016
Subject Category
Instrumentation And Photography
Report/Patent Number
JWST II, Paper 99004-164
GSFC-E-DAA-TN33234
Meeting Information
Meeting: SPIE Astronomical Telescopes + Instrumentation 2016
Location: Edinburgh
Country: United Kingdom
Start Date: June 26, 2016
End Date: July 1, 2016
Sponsors: International Society for Optical Engineering
Funding Number(s)
CONTRACT_GRANT: NNG15CR64C
Distribution Limits
Public
Copyright
Public Use Permitted.
Keywords
wavefront error
Integrated Science Instrument Module
James Webb Space Telescope
image analysis
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