Heat Shield Thermal Conductivity Measurement with Comparative Cut Bar Apparatus

The proposed research activity will be the thermal characterization of heat shield insulation materials used in Thermal Protection Systems (TPS) for planetary probes and space vehicles. The effective thermal conductivity of the porous materials will be experimentally determined through steady state thermal resistance measurements using a comparative cut bar apparatus. The testing will be conducted in a cryogenic vacuum environment to isolate the contributions of solid conduction, gas conduction, and radiation to the apparent thermal conductivity of the insulation materials. By utilizing multiple test samples with varying thicknesses, the contribution of the contact resistance on either side of the test samples will be removed from the calculated apparent thermal conductivity. The empirically determined parameters will enable the development of heat transfer models that will predict the behavior of the insulation materials over a range of environmental conditions. The apparatus will also enable the validation of the models, developed using the empirical parameters, by measuring the apparent thermal conductivity of the insulation materials at elevated pressures and temperatures while exposed to various gas compositions.