Multifunctional Nanostructures with Controllable Band Gap Giving Highly Stable Infrared Emissivity for Smart Thermal Management

Abstract

Thermal control is essential to guarantee the optimal performance of most advanced electronic devices or systems. In space, orbital satellites face the issues of high thermal gradients, heating, and different thermal loads mediated by differential illumination from the Sun. Todayś state-of-the-art thermal control systems provide protection; however, they are bulky and restrict the mass and power budgets for payloads. Here, we develop a lightweight optical superlattice nanobarrier structure to provide a smart thermal control solution. The structure consists of a moisture and outgassing physical barrier (MOB) coupled with atomic oxygen (AO)−UV protection functionality. The nanobarrier exhibits transmission and reflection of light by controlling the optical gap of individual layers to enable high infrared emissivity and variable solar absorptivity (minimum Δα S = 0.30) across other wavelengths. The multifunctional coating can be applied to heat-sensitive substrates by means of a bespoke room-temperature process. We demonstrate enhanced stability, energyharvesting capability, and power savings by facilitating the radiation cooling and facility for active self-reconfiguration in orbit. In this way, the reduction of the operating temperature from ∼120 to ∼60 °C on space-qualified and nonmechanically controlled composite structures is also demonstrated.

Opto-thermo-mechanical phenomena in satellite free-space optical communications: survey and challenges

“…Recent advances in spacecraft thermal control have been significant in both passive and active devices 181 , 182 . Research on passive components includes phase change materials for heat storage to reduce radiator size, 183 materials, such as graphene and aerosols, 184 and multifunctional nanostructure surfaces that modulate the emissivity and absorptivity to optimize the thermal performance 185 . Miniaturization of active thermal devices, such as cryocoolers 181 and pumped fluid loops for small satellites, 186 will be also relevant for future FSOC systems.…”