MIXED HAFNIUM-TANTALUM CARBIDE ROCKET THRUSTER DEVELOPMENT

RECENT AIR FORCE-FUNDED, ARC-JET MATERIALS TESTING HAS DEMONSTRATED THAT A MIXED HFC-TAC COMPOSITE CERAMIC MATERIAL EXHIBITS THE LOWEST MASS LOSS OF ANY MATERIAL TESTED, INCLUDING HAFNIUM CARBIDE AND HAFNIUM DIBORIDE CERAMIC COMPOSITES. A HYDROGEN-OXYGEN PROPELLANT ROCKET THRUSTER, BASED ON THE MIXED HAFNIUM-TANTALUM-CARBIDE CERAMIC COMPOSITE, IS EXPECTED TO DEMONSTRATE SUPERIOR HIGH-TEMPERATURE DURABILITY UNDER STOICHIOMETRIC HYDROGEN-OXYGEN PROPULSION CONDITIONS, WHEN OPERATED EXCLUSIVELY AS A RADIATION-COOLED THRUSTER. PHASE I INCLUDES THE DEVELOPMENT OF TUBULAR COMPOSITES OF HFC-TAC MATRIX WITH GRAPHITE-FIBER REINFORCEMENT. FABRICATION OF CONVERGENT-DIVERGENT SECTIONS WILL BE PERFORMED AS WELL. PROTOTYPE THRUSTER ARTICLES SUITABLE FOR STOICHIOMETRIC HYDROGEN-OXYGEN COMBUSTION EVALUATION AT NASA-LEWIS WILL BE DELIVERED IN PHASE I. PHASE II WORK WOULD FOCUS ON THE DEVELOPMENT OF THRUSTERS IN THE 5,000 LB THRUST CLASS OR SMALLER. THE PAYOFFS FROM SUCH TECHNOLOGY ARE REDUCED THRUSTER WEIGHT, COST, AND COMPLEXITY. ALSO, DRAMATIC IMPROVEMENTS IN SPECIFIC IMPULSE RESULT FROM THE ELIMINATIONOF EXCESS FUEL, WHICH IS INJECTED IN THE COMBUSTION WALL REGION TO AVOID OVERHEATING TEMPERATURE-LIMITED METALLIC THRUSTERS. RECENT AIR FORCE-FUNDED, ARC-JET MATERIALS TESTING HAS DEMONSTRATED THAT A MIXED HFC-TAC COMPOSITE CERAMIC MATERIAL EXHIBITS THE LOWEST MASS LOSS OF ANY MATERIAL TESTED, INCLUDING HAFNIUM CARBIDE AND HAFNIUM DIBORIDE CERAMIC COMPOSITES. A HYDROGEN-OXYGEN PROPELLANT ROCKET THRUSTER, BASED ON THE MIXED HAFNIUM-TANTALUM-CARBIDE CERAMIC COMPOSITE, IS EXPECTED TO DEMONSTRATE SUPERIOR HIGH-TEMPERATURE DURABILITY UNDER STOICHIOMETRIC HYDROGEN-OXYGEN PROPULSION CONDITIONS, WHEN OPERATED EXCLUSIVELY AS A RADIATION-COOLED THRUSTER. PHASE I INCLUDES THE DEVELOPMENT OF TUBULAR COMPOSITES OF HFC-TAC MATRIX WITH GRAPHITE-FIBER REINFORCEMENT. FABRICATION OF CONVERGENT-DIVERGENT SECTIONS WILL BE PERFORMED AS WELL. PROTOTYPE THRUSTER ARTICLES SUITABLE FOR STOICHIOMETRIC HYDROGEN-OXYGEN COMBUSTION EVALUATION AT NASA-LEWIS WILL BE DELIVERED IN PHASE I. PHASE II WORK WOULD FOCUS ON THE DEVELOPMENT OF THRUSTERS IN THE 5,000 LB THRUST CLASS OR SMALLER. THE PAYOFFS FROM SUCH TECHNOLOGY ARE REDUCED THRUSTER WEIGHT, COST, AND COMPLEXITY. ALSO, DRAMATIC IMPROVEMENTS IN SPECIFIC IMPULSE RESULT FROM THE ELIMINATIONOF EXCESS FUEL, WHICH IS INJECTED IN THE COMBUSTION WALL REGION TO AVOID OVERHEATING TEMPERATURE-LIMITED METALLIC THRUSTERS.