Design and thermal modeling of a radiometer for thermal control coatings in situ measurement

To solve the problem of thermal control coatings degradation in space environment, it is necessary to study coatings degradation law in simulated space environment, thus a radiometer design based on calorimetry was proposed for in situ measurement of thermal control coatings solar absorptance. The radiometer structure was designed according to the requirement of in situ measurement. By conducting thermal analysis on radiometer, the heat transfer equations were built and a calculation model based on transient thermal equilibrium was established by energy conservation principle. A SR107 thermal control coating was tested in isoperibol. The experiment result shows a within 3% relative error between the solar absorptance of SR107 and the coating calibration value, with a 5.24% measurement uncertainty. It validates the effectiveness of radiometer experiment and lays a foundation for further development of thermal control coating performance test.