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21 February 1986 Thermal Stability of Lightweight Graphite Glass Sandwich Reflectors for Far Infrared Astronomy
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Graphite fiber reinforced glass matrix composites are being developed for a variety of structural applications requiring excellent thermomechanical stability. These materials are ideally suited for lightweight, high strength, thermally stable infrared mirrors because of their low density, low thermal expansion, high strength and stiffness, and their ability to be machined, replicated and figured using standard polishing techniques. These properties are particularly promising for applications such as a three-meter balloon-borne far-infrared and submillimeter telescope mirror which must be both very lightweight and able to retain its figure accuracy when cycled between room temperature and its operating temperature of -50°C. This paper presents the results of a set of low temperature optical tests conducted to determine the figure stability of a 30 centimeter diameter frit bonded graphite-glass mir-ror in the +20 to -60°C temperature range using a 10.6 micrometer laser interferometer. The results indicate that the residual change in figure was less than 0.3 micrometers rms.
© (1986) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
John H. Bluege, Ramon A. Mayor, and William F. Hoffman "Thermal Stability of Lightweight Graphite Glass Sandwich Reflectors for Far Infrared Astronomy", Proc. SPIE 0571, Large Optics Technology, (21 February 1986);


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