Speaker
Description
Thermal management is critical for high-power density spacecraft electronics, requiring robust heat transport technologies embedded within electronic structures. Copper-water heat pipes are a robust and cost-effective technology where their relatively small size delivers substantial performance compared to traditional AGHP. Their internal wick structure allows for operating capabilities in adverse tilt, thus minimising the orientation restrictions at system level testing. In this context, ADS and Boyd carried out a qualification campaign based on the ECSS-E-ST-31-02C, tailored to the specific needs of the space application. Flight-representative heat pipes were subjected to a series of tests including thermal endurance, mechanical/pressure as well as gamma radiation exposure.
Functional performance tests were performed across a range of saturation temperatures, input powers, and operating angles relative to gravity to fully characterize performance and capture end-of-life (EOL) performance. Following the environmental exposure to the test conditions, including gamma radiation, the heat pipes demonstrated a minor reduction in their thermal transport limit. Targeted low temperature diagnostic tests identified that the reduction in the performance was predominantly attributed to an increased temperature gradient localised within the condenser region, indicating a potential generation of Non-Condensable Gas (NCG). Under nominal operating temperatures, this NCG is compressed into the end of the condenser and imposes no operational constraints while the performance was within specification range. An equivalent (evaporating and condensing) heat transfer coefficient in the range of 15,000 W/m²K was derived and the test data was subsequently used for flight prediction. This paper outlines the qualification methodology and qunatifies the performance degradation at the end of a mission’s life.