Lightweight Primary Mirror Technology

The technical objectives of this Phase 2 activity are to: 1) finalize the design, analysis, and generate drawings for an ultra lightweight primary mirror designed to meet the requirements currently specified on ABL, and 2) design, develop and generate asubscale, aggressively light-weighted primary mirror capable of demonstrating scalability and establishing a foundation for extruded core technology. The specific deliverable item to AFRL for this Phase 2 will be a 0.5 meter extruded core Fused Silicapolished mirror (not coated) made with existing extrusion technology and dies assembled from 5 inch by 5 inch extruded core segments fused to a common face plate and back plate of appropriate thickness to demonstrate that a core with an areal density ofless than 35 kg/m^2 can be manufactured with a curved surface. Additional parameters of the blank envisioned at this time include 0.25 inch by 0.25 inch square cells with 0.030 to 0.040 inch thick cell walls. These parameters may change as other dies forthe extruded process are examined and evaluated for application to mirror technology.