Physical
◦ Lightweight Gas-Fusion mirrors available in excess of 1 m diameter
◦ Gas-Fusion bonding results in 100% bubble-free, monolithic joints; no frits used
◦ Faceplate thickness from 3 mm to 12 mm
◦ Rib thickness from 1 mm to 5 mm
◦ Virtually any outline available: circular, octagonal, rectangular, etc. (see Design Flexibility below.)
◦ Central perforations available
◦ Fused neutral plane mounting bosses
◦ Slumping in meniscus forms, both concave and convex, to f/0.5 while keeping 6:1 aspect ratio
◦ Up to 85% lightweighting available in raw blank; further weight reduction possible during optical fabrication
◦ Areal Densities below 10 kg/m2. (Details)
MATERIAL SPECIFIC DATA: Schott Glass Data Sheet
Mechanical
◦ Self-weight deflection less than a solid blank of same dimensions
◦ Will withstand in excess of 35 g uniform loading
◦ Successfully launched into space in a satellite
◦ Successfully used in turboprop airborne optical systems
◦ Typical residual faceplate stresses are 10nm/cm
◦ All rib-faceplate and rib-rib joints are smooth fillets
◦ Lightweight blanks create equivalent weight saving flow down in supporting structures
Thermal
◦ Thermal CTE is 3.2 X 10-6/°C
◦ Thermal time constant shorter than a solid in proportion to degree of lightweighting
◦ Gas-Fusion™ borosilicate mirrors perform extremely well at cryogenic temperatures, and have been tested at 79°K with less than 1/10l p-v figure change from room tempertature
CRYOGENIC DATA:Cryo_Summary.pdf download
Optical
◦ Figure accuracies of less that 1/20l p-v readily achievable on 0.8 m diameter plano mirrors
◦ 1 m diameter, f/0.5 sphere polished to 1/20l rms
◦ Gas-Fusion mirrors durably coated with all metals and high efficiency dielectric stacks
◦ More on Optical Capabilities
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