High Temperature Lightweight Heat Pipe Panel Technology Development

Lightweight, high temperature capable heat pipe panels are needed for the radiator element of a space nuclear power system. An approach was developed to provide technology for space heat pipe radiators that are lightweight and can reject heat at temperatures in the range from 300 - 550K. The approach resulted from a trade-off of alternative heat pipe and radiator panel materials and configurations. A high conductivity, high temperature capable, organic matrix graphite fiber reinforced composite material was developed to provide the fin for radiating heat from titanium / water heat pipes. A face sheet having a thickness of less than 0.2mm was demonstrated. Graphite foam saddles were used to bridge the round heat pipe configuration to a flat panel design having optimal structural properties. A panel coupon was fabricated from representative materials, assembled and tested at design temperatures in a vacuum to evaluate the durability of organic resins as both the matrix and adhesive material for the sandwich panel. The test showed the ability of GFRC to provide a suitable, lightweight radiator panel at these temperatures.