Emissivity of black plated open honeycomb and black coatings at cryogenic temperatures

Abstract

A cryogenic radiator with high emissivity is required for ultra-sensitive astronomical observation missions. The use of a three-dimensional structure as well as black coatings is effective to achieve high emissivity at cryogenic temperatures. We focused on an open honeycomb with black plating, which has an advantage of low outgassing compared to painting. The emissivity of the open honeycomb with or without black plating and the flat surface with several black coatings was measured using calorimetric methods at 20-80K. The emissivity of the flat surface with a black coating showed a strong dependence on temperature. The black-plated open honeycomb had the highest emissivity up to 0.9, while the emissivity was around 0.5 in the case without black plating. The results suggest that the combination of an open honeycomb and black plating offers a promising solution to achieving high emissivity. © Published under licence by IOP Publishing Ltd.