Stress Coatings for Large Scale Membrane Mirrors

Advanced manufacturing methods have been developed that enable the production of lightweight membrane mirrors from space rated polymer materials (CP1-DE). These materials can be produced with excellent optical quality surface characteristics, ideal forfront surface mirrors, and cast into aspherical shapes for imaging applications. These precision cast membrane mirrors have the potential for reducing the aerial density, packaging volume, and cost of space-based optics by an order of magnitude. Theoptical surface quality of these mirrors is excellent, however, a method is needed to establish and maintain the global figure of these mirrors once deployed. The feasibility of using the intrinsic stress of energetically deposited optical coatings tocontrol the global figure of the membrane mirrors has been demonstrated in previous research on small scale mirrors. This program will demonstrate that method can be applied to manufacture net shape membrane mirrors of large apertures. Recently developedlarge scale casting and coating facilities will be used to demonstrate the technology for a 1.5 meter net shape membrane mirror. At this scale, membrane mirror technology begins to be beneficial to a large class of applications. Additionally this work willshow scalability of the process to much larger sizes.