Enabling Materials and Processes for Large Aerospace Mirrors

摘要

The use of monolithic glass to produce large, rigid segmented members for lightweight space-based mirrorsystems appears to have reached its limits due to the long production lead times, high processing costs, and launchload/weight requirements. New material solutions and processes are required to meet the US Air Force's optical needsfor directed energy, reconnaissance/surveillance, and communications. Mirror structural substrates made out ofadvanced materials (metal, ceramic, and polymer), composites, foams, and microsphere arrays should allow for CTE andmodulus tailorability, low-density, and high values in strength, stiffness, thermal conductivity and toughness.Conventional mechanical polishing to visual specifications for figure and surface finish roughness requirements will bedifficult, due to the multi-phase complexities of these new systems. Advances in surface removal technologies as well asreplication processes will be required to produce the required optical finishes with reduced schedule and cost. In thispaper selected material and process solutions being considered will be discussed.