The Current and Future State-ofthe-art Glass Optics for Space-based Astronomical Observatories

Recent technology advancements show significant promise in the ability to reduce the cost, schedule and risk associated with producing segmented Primary Mirrors (PMs) as well as monolithic optics larger than Hubble Space Telescope (HST) scale to the surface figure and smoothness required of current and future astronomical systems. This paper describes the present state-of-the art technology for glass mirrors at ITT and a path to next generation technology for use in a wide range of applications. In-process development activities will be discussed as well as the areas in which future investments can further enhance glass PM technologies. Active, passive, monolithic, and segmented mirror technologies will be discussed along with some basic descriptions of the different ways by which light-weighted glass mirror blanks are fabricated. There will be an emphasis on Corning’s Ultra Low Expansion (ULE) and borosilicate optics, with some discussion of glass ceramics and other material substrates. The paper closes with a table that summarizes potential areas of investment that will continue to advance the state of the art for the use of glass and other materials in optical systems.