Cryogenic Testing Of Reflective Optical Components And Telescope Systems
11 Oct 1989-Vol. 1113, pp 249-256
TL;DR: In this article, the optical performance of metal mirrors at cryogenic temperatures is investigated and a detailed discussion of the design and fabrication of these mirrors is provided along with a summary of the driving design performance constraints on cryogenic infrared optics.
Abstract: This paper documents and investigates the optical performance of metal mirrors at cryogenic temperatures. It also reviews the telescope system level optical performance for several telescope systems designed and fabricated at SSG. These include data on the LAIRTS Telescope (Large Aperture Infrared Telescope Sensor), the CLAES Telescope (Cryogenic Limb Array Etalon Spectrometer), and the SPIRIT II Telescope (Spatial Infrared Rocketborne Interferometer Telescope). A brief discussion of the design and fabrication of these mirrors is included along with a summary of the driving design performance constraints on cryogenic infrared optics. A review of the test techniques and cryogenic test facilities is given. Interferometric testing is the primary tool used to test these mirrors and systems. This section of the paper also discusses the data analysis methods utilized to determine the cryogenic optical performance of these mirrors.
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18 Apr 2008
TL;DR: In this article, a retrospective is provided on space-based astronomy missions and the prominent role the US Defense Department (DoD), particularly the Air Force, played in early days of infrared astronomy and the technology development that was transitioned to the infrared astronomical community.
Abstract: : A retrospective is provided on space-based astronomy missions and the prominent role the US Defense Department (DoD), particularly the Air Force, played in early days of infrared astronomy and the technology development that was transitioned to the infrared astronomical community The geophysics programs at the Air Force Cambridge Research Laboratories (AFCRL) and successor organizations (AFGL) at Hanscom Air Force Base are described in order to provide a context for the DoD infrared astronomy program AFCRL and AFGL conducted the early mid-infrared probe-rocket based surveys as well as supporting related experiments under university contracts The succession of subsequent orbital experiments is also described
61 citations
Cites background from "Cryogenic Testing Of Reflective Opt..."
...Mather and Smoot shared the 2006 Nobel Prize in Physics for their cosmic background discoveries, particularly for the COBE contributions. Boggess et al. (1992) provide an overview of the COBE instrumentation, mission and initial results....
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13 Oct 1997
TL;DR: In this article, the authors compared the performance of a plated metal mirror with a typical mirror substrate material such as aluminum, using a design example from a near-infrared spectrograph (GNIRS).
Abstract: The optical surfaces of metal mirrors are often plated with electroless nickel to reduce light scattering. The thermalcoefficient of expansion of electroless nickel, 13.5 x 106 rn/rn-K, is significantly different from that of a typical mirrorsubstrate material such as aluminum. A change in temperature produces a "bi-metallic" bending stress in an electrolessnickel plated mirror, which can induce optical surface distortion. Possible solutions to the "bi-metallic" bending effectinclude: metal matrix composites with a thermal coefficient matched to that of the plating, thick mirrors with sufficientstiffness to resist bending, symmetric cross sections producing equal and opposite bending, and plating of both sides of themirror to balance bending deformations. These solutions are compared using a design example from a cryogenic instrument,the Gemini Near Infrared Spectrograph (GNIRS). Deflections are calculated using both finite element and closed formsolutions. The closed form solution produces an order of magnitude estimate, which may not be a reliable guide to the actualtherm-optic performance of a plated metal mirror. More sophisticated analytical techniques, which determine the actual typeof optical surface error, such as focus, piston, and aberration terms, are required to determine the performance of a mirrorundergoing "bi-metallic" bending.Keywords: bi-metallic bending, athermalization, cryogenic optics, metal mirrors, electroless nickel plating, Gemini 8-mtelescope, near-infrared spectrograph, opto-mechanical design
19 citations
DOI•
11 Jul 2017
TL;DR: In this article, the authors consider the self-weight deflection of lightweight mirrors and propose a scaling law to estimate the mirror weight during preliminary design, which can be used to optimize both mirror and mount.
Abstract: Design of lightweight mirrors is a complex problem, involving optimization of both mirror and mount. The expense and complexity of lightweight mirrors requires careful consideration of design requirements. Scaling laws provide rapid estimates of mirror weight during preliminary design. A significant issue is self-weight deflection of lightweight mirrors. The simplest type of lightweight mirror is the contoured back mirror, of which there are three types: symmetric, single arch, and double arch. The sandwich mirror offers the best stiffness-to-weight ratio of any lightweight mirror but is complex to design and fabricate. Open-back mirrors are low in stiffness but are relatively easy to fabricate. Mounting must be considered as part of the mirror design problem.
6 citations
21 Jan 1993
TL;DR: The SPIRIT III instrument as discussed by the authors is the primary infrared instrument on the Mid-Course Space Experiment (MSX) and was designed and built to integrate with a multicolor radiometer and a Michelson interferometer.
Abstract: This paper documents the development of the SPIRIT III telescope from the design through its test activities. The SPIRIT III Instrument is the primary infrared instrument on the Mid-Course Space Experiment (MSX). The telescope is an all reflective optical system consisting of twelve mirrors. The nominal collecting apertures is 14 inches. It was designed and built to integrate with a multicolor radiometer and a Michelson interferometer built by the Space Dynamics Laboratory at Utah State University. Key performance features are discussed, and measured test data is presented. The structural/thermal trade-off issues of a satellite-based cryogenic instrument are presented along with a review of the test techniques and test equipment.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
5 citations