Advanced materials and processes for large, lightweight, space-based mirrors

The use of monolithic glass to produce large, rigid segmented members for lightweight space-based mirror systems has reached its limit due to the long lead times, high processing costs, and launch load/weight requirements. New material solutions and manufacturing processes are required to meet the Air Force's directed energy weapons, reconnaissance/surveillance, and secured communication needs. Mirror structural substrates made out of advanced composite materials (metal, ceramic, and polymer), foams, or microsphere arrays should allow for CTE and modulus tailorability, low-density, and high strength, stiffness, and toughness. Due to the multi-phase complexities of these new systems, mechanical polishing to visual specifications for figure and surface finish roughness requirements will be difficult. New methods of replication and sol-gel or polymer spinning will be required to produce the required optical finishes. In this paper selected material and process solutions will be discussed.(1)