Investigating the performance of a heat sink for satellite avionics thermal management: From ground-level testing to space-like conditions

The thermal management of electronics in space presents unique challenges due to high waste heat generation, miniaturised device footprints, and the absence of convective cooling in vacuum environments. This study investigates the behaviour of a metallic heat sink under varying pressure conditions, from atmospheric pressure to high-grade vacuum, using experimental and numerical approaches. The thermal response of a stainless steel heat sink featuring plate fins was investigated at two power levels to simulate different heat loads of satellite avionics. The experiments revealed a significant rise in operating temperatures under lower pressure conditions, with temperatures in high-grade vacuum exceeding those at atmospheric pressure by up to 66%. A reduced-order numerical model was formulated and validated against experimental data, demonstrating strong agreement and providing an efficient tool for predicting heat sink performance in vacuum conditions. The findings underscore the critical impact of pressure on heat dissipation mechanisms and highlight the need for advanced thermal management strategies tailored for space applications. This work contributes to the understanding of heat sink behaviour across varying pressure environments, offering insights for the design of more effective thermal control in aero- and astrospace technologies. • Experimental evaluation of a 3D-printed stainless steel heat sink. • Conditions assessed were atmospheric, low- grade vacuum, and high-grade vacuum. • Reduced-order numerical model for performance prediction with low computational effort.