Variable Emission Thermal Radiators

Thermal management is an enduring need for a wide range of military and civilian space platforms. In orbit, satellites are regularly exposed to extreme temperature fluctuations. Depending on whether the satellite is exposed to direct sunlight, planet albedo, or if it is in eclipse, temperatures may range from less than -120°C to over 150°C. Traditionally, heaters have been utilized for maintaining warmth of sensitive electronics. These battery-operated heaters significantly increase the satellite’s weight and power usage. Conversely, radiators and reflectors are used to dissipate waste heat and reject thermal loading, respectively, to prevent satellite overheating. The development of autoregulating thermal radiator coatings will therefore greatly improve the thermal control system by minimizing, if not eliminating, the role of active onboard heaters while maintaining necessary radiative and reflective properties. Plasmonics Inc. and Sandia National Laboratories (SNL) proposes to leverage its expertise in design and fabrication of metamaterials and its extensive experience in VO2 thin film processing to develop metasurfaces with optimized temperature-dependent spectral properties to function as variable emissivity thermal control coatings for orbital assets. The band selection afforded by metasurfaces will allow emission to be maximized relative to the expected operating temperature and allow the absorption to be tuned outside of the thermal band.