Stress Coatings for Large Scale Membrane Mirrors

"The need for very large aperture (>10m) mirrors for space applications is pushingcurrent technology to its limits in providing a material and design that meet required launch restraints. The concept of using a membrane mirror would allow a light-weight and deployable primary to become a viable option in multi-meter sized apertureimaging and High Energy Laser systems. To maintain the required shape yet retain the pliability of a membrane, methods of applying thin-film optical coatings to counteract residual stress in the membrane to maintain a prescribed curvature will be developedusing evaporative deposition. This includes metrology techniques to measure the thickness and stress in such coatings, which will be prescribed by finite element analysis. The end result is a coating process to maintain a curvature in a membrane mirrorwith traceability to large-scale production. The successful demonstration of the proposed concept of using stress-coatings tomaintain a curvature in a membrane mirror will provide an immediate impact on manycurrent and future USAF, NASA, and other DoD space-based large aperture imaging orHigh Energy Laser (HEL)applications. Many require multi-meter apertures capable ofbeing deployed after launch. The development of this technology would enable suchdesigns to become a reality and also open the door for commercial parties that areinterested in the use of very large aperture mirrors. This would not be limite