Finite Element Analysis of PCM-Enhanced Passive Thermal Regulation for CubeSats

The thermal environment of outer space poses severe challenges due to the absence of atmosphere, lack of convective heat transfer, microgravity, and extreme temperature variations—from over +120°C in direct sunlight to below −100°C in shadow. Unlike Earth, space systems must operate in a vacuum, where thermal regulation depends solely on conduction and radiation. In such an environment, traditional cooling techniques that rely on fluid-based (hydraulic) or air-based mechanisms are inapplicable. Additionally, mechanical stresses during launch, radiation exposure, and mass and power limitations further constrain thermal management, especially in miniaturized satellites. This study was inspired by a key observation during research on microgravity thermal behaviour and space mission failures — many CubeSats and nano-satellites suffered thermal-induced malfunctions due to poor heat regulation. Recognizing this gap, we proposed the use of Phase Change Materials (PCMs) as a passive thermal control solution. The idea emerged from understanding that PCMs, used in terrestrial energy storage systems, could be re-engineered for space to store and release latent heat during orbital cycles, stabilizing internal satellite temperatures. We targeted CubeSats and small Earth observation satellites due to their growing use in Low Earth Orbit (LEO) missions and their vulnerability to thermal extremes. Our approach began with identifying critical thermal challenges, followed by a comparative study of atmospheric vs. space thermodynamic behaviour. Based on this, we employed a multi-criteria PCM selection process, considering factors such as latent heat capacity, melting point, vacuum compatibility, non- flammability, and long-term stability. Using Finite Element Analysis (FEA) in ANSYS, we simulated real orbital heating and cooling cycles. To counteract the absence of convection, conductive fins, graphene-enhanced spreaders, and radiation-optimized enclosures were integrated with the PCM. Structural design also addressed launch survivability through mechanical reinforcement techniques. The resulting system demonstrated improved thermal uniformity, reduced temperature spikes, and enhanced electronic reliability without adding significant mass or power consumption. This approach provides a sustainable, efficient, and scalable thermal regulation solution for future satellite missions—particularly those in the budget- and volume-constrained CubeSat segment.