Actively Cooled Sapphire Windows

"MSI will design and fabricate actively-cooled sapphire windows containing internal channels for a cooling fluid. The windows will be fabricated from two sapphire plates bonded together with an already-demonstrated index-matching glass. In Phase I, MSIwill (1) develop a preliminary flat sapphire window design based on an analysis of the thermal environment, heat extraction using a cooling fluid (e.g., water), and optical requirements, (2) fabricate a subscale demonstration sapphire window, and (3)develop concepts for integrating the window into a frame that interfaces with the cooling system. In the Phase I Option, MSI will (1) refine concepts for integrating the actively-cooled window into the missile system and (2) initiate the detailed designof the window itself. In Phase II, MSI will design, build, and test a prototype system to demonstrate its efficacy at air speeds up to Mach 3 and altitudes as low as 1000 ft. The applicability of the actively-cooled window system to non-planar windowgeometries will also be demonstrated. This program will provide new actively-cooled sapphire IR windows capable of full optical performance during hypersonic flight conditions, thereby enhancing the performance and reliability of surface-to-air interceptormissiles and tactical aircraft."