CARBON THERMOPHYSICAL PROPERTY MEASUREMENTS AT THE TRIPLE POINT

THE MELT TEMPERATURE, HEAT OF FUSION, LIQUID VISCOSITY, AND ULTRAHIGH TEMPERATURE STRENGTH OF GRAPHITE AND CARBON-CARBON MATERIALS ARE UNCERTAIN AND OF SUBSTANTIAL INTEREST RELATIVE TO NOSETIP PERFORMANCE IN ADVANCED EARTH ENTRY MISSIONS. THE OBJECTIVE OF THIS PROJECT IS TO USE COMPONENTS OF A UNIQUE AND AVAILABLE FACILITY--THE NASA AMES ELECTRIC ARC SHOCK TUBE (EAST)--TO RAPIDLY RESISTANCE HEAT CARBON SPECIMENS TO THE TRIPLE POINT, AND MEASURE THESE THERMOPHYSICAL PROPERTIES. THE HIGH ENERGY CAPACITY AT EAST (1.25 MJ) ENABLES MILLISECOND TIME SCALE HEATING WHICH HELPS TO CIRCUMVENT MANY OF THE PROBLEMS WHICH HAVE THWARTED PREVIOUS MEASUREMENTS ATTEMPTS. ON PHASE I, WE WILL EXPERIMENTALLY DEMONSTRATE THE BASIC FEASIBILITY OF THIS APPROACH AND DESIGN QUANTITATIVE MEASUREMENT EXPERIMENTS. ON PHASE II, WE WILL CARRY OUT THE DETAILED THERMOPHYSICAL PROPERTY MEASUREMENT TESTS.