Experimental setup recreates wide temperature swings of space for heat transfer materials testing

The approach covers background temperatures from 80 to 800 Kelvin to evaluate novel variable-emittance coatings for spacecraft thermal control. In extreme temperature environments, radiative heat transfer dominates the thermal design of spacecraft, making the study of dynamic radiative processes essential. Several variable-emittance coatings have been proposed, capable of passive tuning by temperature or active control by external stimuli, yet there was no established method to thermally test them in a space-like environment. A new experimental setup was developed to test self-adaptive dynamic radiative heat transfer with variable-emittance coatings under space-like thermal conditions. Samples were housed in a vacuum cryostat using a cold trap. An absorptive black coating and highly reflective tungsten mirrors were calibrated to account for energy consumed by auxiliary components, termed the parasitic head load, and to calibrate heat flux sensor sensitivity. The device can detect coating temperature and variable radiative heat dissipation under differing thermal loads within background temperatures ranging from 80 to 800 Kelvin.

“Our approach provides a way to directly demonstrate thermal homeostasis and thermal rectification, which are important for maintaining a spacecraft’s temperature within operational range with reduced power consumption,” said author Liping Wang.

Keywords: variable-emittance coatings, space environment, radiative heat transfer, thermal homeostasis, thermal rectification, vacuum cryostat, parasitic head load, heat flux sensor calibration.

AIP.ORG — 2025-11-21

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