LOW-MASS INTRINSICALLY-HARD HIGH TEMPERATURE RADIATOR

STRATEGIC DEFENSE REQUIREMENTS FOR HIGH-TEMPERATURE WASTE HEAT REJECTION INCLUDE A NEED FOR HARDENED, LIGHTWEIGHT RADIATOR EQUIPMENT TO OPERATE NEAR 875 DEGREES KELVIN. CURRENT DESIGNS UNDER CONSIDERATION PLANS TO USE MATERIALS SUCH AS ITIANIUM COMPOSITE AS THE HEAT PIPE RADIATOR WALL MATERIAL. THIS MATERIAL IS POTENTIALLY DIFFICULT TO FABRICATE IN A THIN-WALLED VACUUM-TIGHT VESSEL. IT IS ALSO RELATIVELY VULNERABLE TO THREATS COMPARED TO REFRACTORYMETAL DESIGNS DUE TO ITS RELATIVELY LOW-MELTING POINT. A NEW NIOBIUM COMPOSITE MATERIAL IS BEING DEVELOPED IN THIS STUDY AS AN ALTERNATIVE TO TITANIUM COMPOSITES. THIS MATERIALS SHOWS PROMISE FOR SURVIVABILITY, WELDABILITY, NEUTRON ABSORBTIVITY, DEBRIS AND MICROMETEOROID RESISTANCE, AND 3 TO 5 KG/M2 RADIATOR MASS WHILE SERVING AS A WALL MATERIAL FOR HIGH TEMPERATURE RADIATOR COMPONENTS. IN THIS PROGRAM, THE FEASIBILITY OF ADVANCED REFRACTORY COMPOSITES AS A HARDENED RADIATOR WALL MATERIAL IS BEING INVESTIGATED. REQUIREMENTS ARE BEING DEFINED AND USED AS A BASIS FOR A COMPLETE 875 DEGREE KELVIN HEAT REJECTION SYSTEM DESIGN. IMPROVED RESISTANCE TO THREATS ARE BEING DEMONSTRATED BY ANALYSIS. A VACUUM TIGHT LIQUID METAL HEAT PIPE IS BEING FABRICATED USING A NIOBIUM COMPOSITE MATERIAL. HYPERVELOCITY PARTICLE BUMPERING CAPABILITY IS BEING DEMONSTRATED BY EXPERIMENT. SUCCESSFUL DEVELOPMENT OF THIS MATERIAL INTO A HEAT PIPE RADIATOR WOULD PROVIDE STATE-OF-THE-ART LIGHTWEIGHT HIGH TEMPERATURE RADIATORS. THIS MATERIAL WOULD ALSO BE AN IMPORTANT AEROSPACE MATERIAL ALTERNATIVE FOR APPLICATIONS. IT WOULD ALSO REPRESENT A SIGNIFICANT ADVANCE IN REDUCTION OF WALL THICKNESS FOR VACUUM-TIGHT ENVELOPES TO BE OPERATED AT 1000 DEGREES CELSIUS AND ABOVE.