Survey of interferometric techniques used to test JWST optical components

Stahl, H. Philip; Alongi, Chris; Arneson, Andrea; Bernier, Rob; Brown, Bob; Chaney, Dave; Cole, Glen; Daniel, Jay; Dettmann, Lee R.; Eng, Ron; Gallagher, Ben; Garfield, Robert E.; Hadaway, James B.; Johnson, Patrick; Lee, Allen; Leviton, Doug; Magruder, Adam; Messerly, Michael J.; Patel, Ankit; Reardon, Pat; Schwenker, John P.; Seilonen, M.; Smith, Koby; Smith, W. S.

doi:10.1117/12.862234

Cited by 13 publications

(10 citation statements)

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“…9 Metrology error is the uncertainty to which the SFE is measured and is set to what was demonstrated on JWST. 10 The last two boxes define specific PM error contributors: uncertainty in the ability to quantify and remove coefficient of thermal expansion (CTE) homogeneity effects and uncertainty in the ability to quantify and remove gravity sag from the PM surface shape.…”

Section: Diffraction-limited Performancementioning

confidence: 99%

Habitable-Zone Exoplanet Observatory baseline 4-m telescope: systems-engineering design process and predicted structural thermal optical performance

Stahl

Kuan

Arnold

et al. 2020

J. Astron. Telesc. Instrum. Syst.

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The Habitable-Zone Exoplanet Observatory Mission (HabEx) is one of four large missions under review for the 2020 astrophysics decadal survey. Its goal is to directly image and spectroscopically characterize planetary systems in the habitable zone around nearby Sun-like stars. In addition, HabEx will perform a broad range of general astrophysics science enabled by a 115-to 1700-nm spectral range and 3 × 3 arcminute field of view. Critical to achieving its science goals, HabEx requires a large, ultrastable UV/optical/near-IR telescope. Using sciencedriven systems engineering, HabEx specified its baseline telescope to be a 4-m off-axis, unobscured three-mirror anastigmatic architecture with diffraction-limited performance at 400 nm, and wavefront stability on the order of a few tens of picometers. We summarize the systems-engineering approach to the baseline telescope assembly's optomechanical design, including a discussion of how science requirements drive the telescope's specifications. We also present structural thermal optical performance analysis showing that the baseline telescope structure meets its specified tolerances. We report new and updated analysis that is not in the HabEx final report. © The Authors. Published by SPIE under a Creative Commons Attribution 4.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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Section: Diffraction-limited Performancementioning

confidence: 99%

Habitable-Zone Exoplanet Observatory baseline 4-m telescope: systems-engineering design process and predicted structural thermal optical performance

Stahl

Kuan

Arnold

et al. 2020

J. Astron. Telesc. Instrum. Syst.

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show abstract

“…As the largest aerospace telescope, James Webb Space Telescope, using Leitz CMM to control radius of curvature, conic constant and aspheric figure for primary mirror, secondary mirrors and tertiary mirror during generation and rough polishing. Besides, CMM is also used to assist the alignment of the primary mirror segment assembly (PMSA) to determine its contribution to the shim prescription [7][8] . W.C. Lin and S.T.…”

Section: Introductionmentioning

confidence: 99%

The alignment and isostatic mount bonding technique of the aerospace Cassegrain telescope primary mirror

Lin¹,

Chang²,

Lin³

et al. 2012

SPIE Proceedings

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In order to meet both optical performance and structural stiffness requirements of the aerospace Cassegrain telescope, iso-static mount is used as the interface between the primary mirror and the main plate. This article describes the alignment and iso-static mount bonding technique of the primary mirror by assistance of CMM. The design and assembly of mechanical ground support equipment (MGSE) which reduces the deformation of primary mirror by the gravity effect is also presented. The primary mirror adjusting MGSE consists of X-Y linear translation stages, rotation stage and kinematic constrain platform which provides the function of decenter, orientation, tilt and height adjustment of the posture sequentially. After CMM measurement, the radius of curvature, conic constant, decenter and tilt, etc. will be calculated. According to these results, the posture of the mirror will be adjusted to reduce the tilt by the designed MGSE within 0.02 degrees and the distance deviation from the best fitted profile of mirror to main plate shall be less than 0.01 mm. After that, EC 2216 adhesive is used to bond mirror and iso-static mount. During iso-static mount bonding process, CMM is selected to monitor the relative position deviation of the iso-static mount until the adhesive completely cured. After that, the wave front sensors and strain gauges are used to monitor the strain variation while the iso-static mount mounted in the main plate with the screws by the torque wrench. This step is to prevent deformation of the mirror caused from force of the iso-static mount during the mounting process. In the end, the interferometer is used for the optical performance test with +1G and -1G to check the alignment and bonding technique is well or not.

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Section: Introductionmentioning

confidence: 99%

The alignment of the aerospace Cassegrain telescope primary mirror and iso-static mount by using CMM

Lin¹,

Chang²,

Lin³

et al. 2011

SPIE Proceedings

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In order to meet both optical performance and structural stiffness requirements of the aerospace Cassegrain telescope, the primary mirror shall be mounted with the main plate by iso-static mount. This article describes of the alignment of the aerospace Cassegrain telescope's primary mirror and iso-static mount by using coordinate-measuring machine (CMM), and the design and assembly of mechanical ground support equipment (MGSE). The primary mirror adjusting MGSE consists of three 3-axis linear stages and point contact platforms, which hold the mirror while avoid the rotated movement when adjusting the stage. This MGSE provide the adjustment of tilt and height for the mirror. After the CMM measurement, the coordinates of measured point on the mirror will be analyzed by the software based on least square fitting to find the radius of curvature, conic constant, de-center and tilt, etc. According to these results, the mirror posture will be adjusted to reduce de-center and tilt by the designed MGSE. The tilt in x and y direction are reduced within 0.001 degrees and the distance deviation from the best fitted profile of the mirror to the main plate shall be less than 0.008mm.

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Survey of interferometric techniques used to test JWST optical components

Cited by 13 publications

References 0 publications

Habitable-Zone Exoplanet Observatory baseline 4-m telescope: systems-engineering design process and predicted structural thermal optical performance

Habitable-Zone Exoplanet Observatory baseline 4-m telescope: systems-engineering design process and predicted structural thermal optical performance

The alignment and isostatic mount bonding technique of the aerospace Cassegrain telescope primary mirror

The alignment of the aerospace Cassegrain telescope primary mirror and iso-static mount by using CMM

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