&lt;title&gt;Final results of the Subscale Beryllium Mirror Demonstrator (SBMD) program&lt;/title&gt;

Reed, Timothy; Kendrick, Stephen E.; Brown, Robert; Hadaway, James B.; Byrd, Donald A.

doi:10.1117/12.453614

Cited by 10 publications

(6 citation statements)

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“…The deposited gold coating introduced no discernible cryogenic surface figure distortion into SBMD. The uncoated SBMD's 30 K surface figure was 52.8 nm rms, and its coated 30 K surface figure was 53.9 nm rms 35 (Fig. 9).…”

Section: Requirements Verificationmentioning

confidence: 95%

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Webb Space Telescope primary mirror development: summary and lessons learned

Stahl

2024

J. Astron. Telesc. Instrum. Syst.

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The primary mirror is central to the success of the Webb Space Telescope and the product of 100s of engineers and technologists who invented technologies and processes for its manufacture and test. We summarize the Webb mirror technology development program, explain how the technology was demonstrated to be TRL-6 (including the importance of an Engineering Development Unit), and list some of the author's personal lessons learned.

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Section: Requirements Verificationmentioning

confidence: 95%

“…The predicted final cryogenic surface figure was 14.4 nm rms. The actual final cryogenic surface error was 18.8 nm rms 35 (Fig. 13).…”

Section: Requirements Verificationmentioning

confidence: 98%

Webb Space Telescope primary mirror development: summary and lessons learned

Stahl

2024

J. Astron. Telesc. Instrum. Syst.

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“…With a diameter of approximately 0.5 m and an adjustable RoC, the SBMD showed, among other requirements, a surface figure roughness of less than λ/4 p-v at λ = 633 nm under cryogenic vacuum conditions. 12 Experience from SBMD was applied to the Advanced Mirror System Demonstrator (AMSD), a 1.4 m diameter rib-stiffened beryllium hexagonal mirror segment with four degrees of freedom (piston, tip/tilt, RoC). Cryogenic performance of this mirror also met requirements and results were used to guide JWST segment design.…”

Section: Prior Workmentioning

confidence: 99%

Minimizing actuator-induced errors in active space telescope mirrors

Smith

Miller

2010

SPIE Proceedings

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The trend in future space telescopes points toward increased primary mirror diameter, which improves resolution and sensitivity. However, given the constraints on mass and volume deliverable to orbit by current launch vehicles, creative design solutions are needed to enable increased mirror size while keeping mass and volume within acceptable limits. Lightweight, segmented, rib-stiffened, actively controlled primary mirrors have emerged as a potential solution. Embedded surface-parallel actuators can be used to change the mirror prescription onorbit, lowering mirror mass overall by enabling lighter substrate materials such as silicon carbide (SiC) and relaxing manufacturing constraints. However, the discrete nature of the actuators causes high spatial frequency residual errors when commanding low-order prescription changes. A parameterized finite element model is used to simulate actuator-induced residual error and investigate design solutions that mitigate this error source. Judicious specification of mirror substrate geometry and actuator length is shown to reduce actuator-induced residual while keeping areal density constant. Specifically, a sinusoidally-varying rib shaping function is found to increase actuator influence functions and decrease residual. Likewise, longer actuators are found to offer reduced residual. Other options for geometric shaping are discussed, such as rib-to-facesheet blending and the use of two dimensional patch actuators.

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“…It was upgraded to allow for interferometric testing for the SBMD and NMSD programs by the addition of a helium shroud, a wavefront sensor support structure, and the development of a unique wavefront sensor pallet containing a suite of 3 wavefront and one distance measuring instruments. A series of successful measurements proved out the facility for further testing [4][5][6] .…”

Section: Introductionmentioning

confidence: 99%

<title>AMSD test error budget sensitivity analysis</title>

et al. 2001

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The AMSD testing program is all encompassing. Optical, mechanical, and modeling results are all being investigated, and each of these has a number of facets. The subject of this paper is the optical test program being conducted at the XRCF in Huntsville, AL. The focus of this paper is the cryogenic surface metrology of the mirrors at the NASA's XRay Cryogenic Facility (XRCF) at the Marshall Space Flight Center (MSFC). The paper presents the interferometer selection, null optics, and radius of curvature measurement method. The error budgeting process is also presented, and the initial test approach to successfully carry out the tests will be discussed.

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<title>Final results of the Subscale Beryllium Mirror Demonstrator (SBMD) program</title>

Cited by 10 publications

References 0 publications

Webb Space Telescope primary mirror development: summary and lessons learned

Webb Space Telescope primary mirror development: summary and lessons learned

Minimizing actuator-induced errors in active space telescope mirrors

<title>AMSD test error budget sensitivity analysis</title>

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