Ultra-Lightweight "Meter" Class Optics

This program will provide meter class CERAFORM (TM) Silicon Carbide mirrors with an areal density of < 2 kg/mm2 for use in space based laser and surveillance systems. Providing larger, stiffer structures, CERAFORM (TM) SiC provides optical, structural and thermal properties which exceed that of the glasses such as Zerodur and ULE, the composites such as graphite epoxy, and the metals such as aluminum and beryllium. Lightweight glass designs have been produced with an areal density of < 15 kg/mm2 by using costly diamond milling techniaues. Recent developments in SiC forming have produced SiC mirrors with areal density of < 7.5 kg/mm2 with a potential to achieve an areal density of < 2 kg/mm2. These will provide the needed optical material for the next generation of flight based optical systems providing significant technical advantage over current material and fabrication techniques. Phase I will provide a representative-scale demonstration article, a set of designs, performance predictions and manufacturing plans for the meter class SiC mirror. Phase II will fabricate a (nominal) 1 meter scale demonstration article, designed to have wall and facesheet thickness commensurate with the 2 kg/mm2. Critical performance requirements of low temperature thermal response and structural response to launch loads and low level dynamic environment will be among the properties of the test article to be demonstrated. Other issues are the facility cost, environmental impact of the fabrication process, and the risk of development of all manufacturing processes, including demonstration of high quality optical surfaces without print-through. - Mirror for NASA based missions such as Next Generation Space Systems (NGSS) and Space Infra Red Telescope Facility (SIRTF). - Lightweight stiff mirror applications, including high speed tip-tilt mirrors and secondary mirrors for ground based telescope systems, particularly those in a stressing thermal environment.