High Structural Efficiency, Silicon Lightweight Mirrors (SLMS)

"Schafer proposes to further develop Silicon Lightweight Mirrors (SLMs) technology, an all silicon foam-core composite mirror material that is extremely stiff, highly polishable and low cost. High structural efficiency primary mirrors are required for theAir Force Deployable Optical Telescope System (DOTS) and the Airborne Laser (ABL). SLMS technology would greatly reduce the weight of the ABL telescope. SLMS technology has an order of magnitude higher specific stiffness than ULE and offers a potentialweight savings of the PM of >250 lbs. Thus, 600 lbs or more are realizable in just the Telescope Assembly of ABL. The complete Turret Ball Assembly weight savings is estimated to be greater than this due to weight savings in the Gimbal Assembly.In the Phase I project, Schafer and teammates Brashear LP and ERG would produce two, spherical, 12.7 cm diameter lightweight SLMs mirrors that demonstrate the DOTS performance goals. During the Phase II project we would leverage the experience gained fromthe Phase I project, to manufacture two 60 cm diameter DOTS primary mirrors. Finally, in Phase II, the team would initiate the activities required to produce a near-net shape 1.5 meter diameter SLMs substrate for use as an ABL primary mirror prototype. The competitive advantages of SLMs technology as opposed to other materials for high-energy laser beam director are its superior properties and ease of fabrication. Optical glasses, such as ultral