Thermal Control for Small Satellites

The Air Force seeks to provide next-generation thermal control technology to enable high performance, resilient small satellites for the hybrid space architecture. Technologies must be leveraged to reduce spacecraft overall size, weight, power, cost, and operational constraints and increase spacecraft overall reliability, capability, and operational agility.     Thermal control is generally provided by heat pipes coupled to heat sinks or phase change materials (PCMs), with paraffin and other similar materials that undergo a solid-liquid transformation being the most common. The liquid phase of PCM requires encapsulation in the vacuum environment of space to prevent boiling and material loss. Aluminum is commonly used to encapsulate the PCM, and its energy storage is minor. At the same time, paraffin-like PCMs have very low thermal conductivity and as a result, charge and discharge slowly. The structure of the aluminum container can help channel heat into the PCM but at the cost of additional aluminum. Triton systems proposes to develop an alternative PCM that undergoes a solid-solid phase transformation and that has thermal conductivity about 10 times that of paraffin PCMs. We propose that this material be substituted for aluminum as an encapsulant for paraffin PCM. While its thermal conductivity is lower than aluminum, it has a very high volumetric latent heat. PCM thermal management systems of this type have been shown to outperform aluminum encapsulated paraffin and will result in reduced PCM system volume and high-rate thermal charging. This technology will help the Air Force achieve their objectives in next generation small satellites.