Heat Flux-Based Calorimeter for Active Thermal Coatings

We propose to develop a space-ready instrument that can accurately measure the emissivities, absorptivities, and long term stabilities of several passive and active coatings or thermal structures simultaneously. This technique provides a direct measure of the heat flowing through the surface using heat flux sensors, so the performances of the thermal control materials mounted on these sensors are obtained directly. This technique makes the thermal properties and temperature history of the substrate on which the test surface is installed irrelevant to the emissivity/absorptivity measurement, eliminating the need for thermal insulation of the test surface from the rest of structure. This advantage enables our technique to test multiple samples on the same device or the monitoring for spatial variations across a single thermal device. The small size of the sensors will allow the necessary spatial resolution to resolve the performance variation across the active coatings or thermal structures. Our prototype will include the necessary electronics to perform tests and collect data while deployed in orbit. The required tests will be performed to insure the delivery of a space-certified system.