Variable Thermal Conductivity Metamaterials Applied to Passive Thermal Control of Satellites

Abstract

Active materials, such as the proposed variable thermal conductivity metamaterial, enables new thermal designs and low-cost, low-power, passive thermal control. Thermal control of satellites conventionally requires active thermal control systems that are expensive, large, inefficient, energy-intensive, and unavailable for CubeSats. For CubeSats, the thermal system's primary design consideration is the high-temperature operation case. The thermal path is designed to reject as much heat as possible to prevent overheating. In other cases, such as during a power anomaly, the oversized thermal path results in rapid cooling, culminating in mission failure due to thermal limits on the electronics or batteries. Improving the thermal control of CubeSats can enable new thermally challenging missions, increase satellite longevity, and increase mission success rate by controlling and dynamic thermal environment. The materials available for thermal management are limited, but new engineered materials provide unique opportunities to change how satellites adapt to dynamic environmental and thermal loads. This paper investigates using an adaptive metamaterial designed to passively change its thermal conductivity as a function of temperature to meet the needs of the satellite. The thermal performance of a CubeSat is evaluated with a variable thermal conductivity metamaterial located in the critical thermal path from the satellite to the radiator. The system's performance using two metamaterial configurations is compared to a baseline copper thermal path. Multiple satellite thermal operation cases are investigated to determine the operation ranges, and the metamaterial's performance in various conditions is quantified.