This paper reviews the key physical properties of ULE glass and the various fabrication techniques available for making lightweight mirrors. Special emphasis is given to ULE's mechanical behavior which controls the long-term reliability of mirror blanks during fabrication, shipping, installation, and operation. It describes the 8-meter class mirror blank manufacturing process and the stress/time histories to which such blanks are exposed. These parameters, together with strength and fatigue data, were used to optimize surface finish for adequate strength and to evaluate an 8-meter blank support system to ensure long-term reliability of the blank during transportation. The paper concludes with recent advances and development programs in support of the manufacture of precision optical mirror blanks.
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Suresh T. Gulati, Mary J. Edwards, "ULE - Zero expansion, low density, and dimensionally stable material for lightweight optical systems," Proc. SPIE 10289, Advanced Materials for Optics and Precision Structures: A Critical Review, 1028909 (28 July 1997);