Demonstration of the James Webb Space Telescope commissioning on the JWST testbed telescope

Acton, D. Scott; Towell, Timothy C.; Schwenker, John P.; Swensen, John; Shields, Duncan M.; Sabatke, Erin; Lana, Klingemann,; Contos, Adam R.; Bauer, Brian; Hansen, Knud Erik; Atcheson, Paul D.; Redding, David C.; Basinger, Scott A.; Dean, Bruce H.; Burns, Laura A.

doi:10.1117/12.672133

Cited by 22 publications

(20 citation statements)

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“…A schematic diagram of the WFS&C procedure used during initial commissioning is shown in Figure 1. Details of the WFS&C commissioning process are provided elsewhere [2]. In the present context, it suffices to limit our discussion to the fine phasing process, the focus of the GSFC blind test studies of the iterative-control algorithm for optimizing the OTE degrees of freedom.…”

Section: Wavefront Sensing and Control Process Overviewmentioning

confidence: 99%

Alignment estimation and control of the James Webb Space Telescope mirrors using decomposition of an influence matrix

Shiri

Howard

Aronstein

2011

Integrated Modeling of Complex Optomechanical Systems

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The James Webb Space Telescope (JWST) is a three-mirror anastigmatic telescope. For a "blind" telescope alignment estimation and control study at the Goddard Space Flight Center (GSFC), influence functions for each of the primary mirror's 18 segments (6 degrees of freedom each) and for the secondary mirror (5 degrees of freedom) were used to construct a 113-element influence matrix. The singular value vector obtained from pseudoinverse of this influence matrix indicates that the most dominant modes in the control of the telescope are rotation, piston, clocking and translation, in order of significance. The application of an iterative-control algorithm to ten cases of random misalignments, involving both the primary segmented mirror and secondary mirror, shows strong convergence after 5 iterations in most of the cases.

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Section: Wavefront Sensing and Control Process Overviewmentioning

confidence: 99%

Alignment estimation and control of the James Webb Space Telescope mirrors using decomposition of an influence matrix

Shiri

Howard

Aronstein

2011

Integrated Modeling of Complex Optomechanical Systems

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“…4 The TBT and recent commissiong results are discussed in Section 4 and other sources. 4,9,10 Additionally for this two-segment simulation, we stipulate that each segment has an uncorrelated jitter, producing a much smaller, random piston, tip, and tilt across both segments. This is realistic of how such an optical system behaves, even if the jitter is relatively small.…”

Section: Two-segment Simulationmentioning

confidence: 99%

Co-adding techniques for image-based wavefront sensing for segmented-mirror telescopes

et al. 2007

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Image-based wavefront sensing algorithms are being used to characterize the optical performance for a variety of current and planned astronomical telescopes. Phase retrieval recovers the optical wavefront that correlates to a series of diversity-defocused point-spread functions (PSFs), where multiple frames can be acquired at each defocus setting. Multiple frames of data can be co-added in different ways; two extremes are in "image-plane space," to average the frames for each defocused PSF and use phase retrieval once on the averaged images, or in "pupil-plane space," to use phase retrieval on each PSF frame individually and average the resulting wavefronts. The choice of co-add methodology is particularly noteworthy for segmented-mirror telescopes that are subject to noise that causes uncorrelated motions between groups of segments. Using models and data from the James Webb Space Telescope (JWST) Testbed Telescope (TBT), we show how different sources of noise (uncorrelated segment jitter, turbulence, and common-mode noise) and different parts of the optical wavefront, segment and global aberrations, contribute to choosing the co-add method. Of particular interest, segment piston is more accurately recovered in "image-plane space" co-adding, while segment tip/tilt is recovered in "pupil-plane space" co-adding.

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“…2 IEEEAC paper #1083, Version 4, Updated February 10, 2007 Since the days of HST, phase retrieval has matured as viable technology for space missions requiring active optical correction and control. In fact, the successor to HST, the James Webb Space Telescope (JWST) [2] will incorporate a phase retrieval based system in four of its eight optical commissioning steps [3]. Therefore, it is of renewed interest to analyze the HST data sets using the phase retrieval algorithm [4] developed and baselined for JWST flight.…”

Section: Introductionmentioning

confidence: 99%

Looking at Hubble through the Eyes of JWST

Dean

2007

2007 IEEE Aerospace Conference

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Demonstration of the James Webb Space Telescope commissioning on the JWST testbed telescope

Cited by 22 publications

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Alignment estimation and control of the James Webb Space Telescope mirrors using decomposition of an influence matrix

Alignment estimation and control of the James Webb Space Telescope mirrors using decomposition of an influence matrix

Co-adding techniques for image-based wavefront sensing for segmented-mirror telescopes

Looking at Hubble through the Eyes of JWST

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