Performance of the center-of-curvature optical assembly during cryogenic testing of the James Webb Space Telescope

Hadaway, James B.; Wells, Conrad; Olczak, Gene; Waldman, Mark; Whitman, Tony; Cosentino, Joseph; Zarella, Michael; Connolly, Mark; Chaney, David; Telfer, Randal

doi:10.1117/12.2315762

Cited by 7 publications

(6 citation statements)

References 1 publication

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“…Fortunately the hurricane did not preclude safely continuing the test. All significant goals for the test were achieved, including confirming the health of the OTIS payload after its environmental test program (Wolf et al 2018), accomplishing the planned optical verifications and cross-checks (e.g., Hadaway et al 2018), validating the OTIS thermal model and the OTIS thermal distortion model, both required for the Integrated Modeling of the observatory as a whole, and various operational validations and demonstrations.…”

Section: The Pathfinder Programmentioning

confidence: 99%

The James Webb Space Telescope Mission: Optical Telescope Element Design, Development, and Performance

McElwain

Feinberg

Perrin

et al. 2023

PASP

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The James Webb Space Telescope (JWST) is a large, infrared space telescope that has recently started its science program which will enable breakthroughs in astrophysics and planetary science. Notably, JWST will provide the very first observations of the earliest luminous objects in the universe and start a new era of exoplanet atmospheric characterization. This transformative science is enabled by a 6.6 m telescope that is passively cooled with a 5 layer sunshield. The primary mirror is comprised of 18 controllable, low areal density hexagonal segments, that were aligned and phased relative to each other in orbit using innovative image-based wave front sensing and control algorithms. This revolutionary telescope took more than two decades to develop with a widely distributed team across engineering disciplines. We present an overview of the telescope requirements, architecture, development, superb on-orbit performance, and lessons learned. JWST successfully demonstrates a segmented aperture space telescope and establishes a path to building even larger space telescopes.

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Section: The Pathfinder Programmentioning

confidence: 99%

The James Webb Space Telescope Mission: Optical Telescope Element Design, Development, and Performance

McElwain

Feinberg

Perrin

et al. 2023

PASP

Self Cite

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“…• Medium-timescale (t C ∼ 2 − 6 hours) drifts in response to changes in test chamber thermal state, in particular the opening and closing of the COCOA interferometer shutter. 30 Investigations after the OTIS test diagnosed this as due to insufficient slack in portions of the OTE "frill" stray light baffle and the insulation closeouts around the primary mirror segment assemblies' edges, and these portions of the OTE were reworked to achieve the correct clearances. However since the rework could not be tested in a second OTIS cryo test, there remains some uncertainty about the eventual on-orbit behavior.…”

Section: Ote Stability and Otis Testing Resultsmentioning

confidence: 99%

Updated optical modeling of JWST coronagraph performance contrast, stability, and strategies

Perrin

Pueyo

Gorkom

et al. 2018

Space Telescopes and Instrumentation 2018: Optical, Infrared, and Millimeter Wave

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We update performance simulations and contrast predictions for JWST's coronagraphs based on the latest information on the as-built telescope and instrument properties, including both static and dynamic contributions to wavefront error. By combining optical modeling of the telescope, instruments and coronagraph optics along with STScI's rigorously-validated exposure time calculation engine, we develop updated contrast models including contributions from effects such as target acquisition residuals, stellar color differences, etc. We present assessments of the impact of wavefront error changes over time between science and PSF reference stars, using modeled wavefront drifts on various timescales based on available observatory structural/thermal/optical modeling and tested performance during the OTIS cryo test, extrapolated to on-orbit conditions. For NIRCam we explore tradeoffs between different occulting masks at a given wavelength. Between now and the start of Cycle 1 science, these and other updated simulations will enable the science community to prepare analysis tools and PSF subtraction software to hit the ground running with JWST coronagraphic observations.

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“…And the hurricane was coming. See Hadaway et al (2018) 14 for additional details. PG data similarly guided the rough alignment of the SM, before that process was ultimately completed with Pass-and-a-Half observations.…”

Section: Photogrammetry Performance and Resultsmentioning

confidence: 99%

“…Comparison of the final observed surface shape for the PM segments was also in excellent agreement with model predictions for these light-weight beryllium segments on their hexapod mounts in a 1-g field (Figure 14). Again see Hadaway et al (2018) 14 for details.…”

Section: Mirror Alignment and Phasing Results (Cocoa Interferometry)mentioning

confidence: 99%

James Webb Space Telescope (JWST) optical telescope element and integrated science instrument module (OTIS) cryogenic test program and results

Kimble

Feinberg

Voyton

et al. 2018

Space Telescopes and Instrumentation 2018: Optical, Infrared, and Millimeter Wave

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Performance of the center-of-curvature optical assembly during cryogenic testing of the James Webb Space Telescope

Cited by 7 publications

References 1 publication

The James Webb Space Telescope Mission: Optical Telescope Element Design, Development, and Performance

The James Webb Space Telescope Mission: Optical Telescope Element Design, Development, and Performance

Updated optical modeling of JWST coronagraph performance contrast, stability, and strategies

James Webb Space Telescope (JWST) optical telescope element and integrated science instrument module (OTIS) cryogenic test program and results

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