An interdisciplinary research team including mechanical science and engineering professor Mickey Clemon in The Grainger College of Engineering at the University of Illinois Urbana-Champaign is investigating cooling methods for heat sinks by performing experiments onboard a satellite currently orbiting the earth.
"University-sponsored satellites have a very low success rate of making it into space, so we're very happy that we made it into space and that our system works," Clemon said.
Thermal management for electronics in space poses a unique set of challenges due to high waste heat generation and the lack of convective cooling in a vacuum. Thus, systems operating in space must either effectively release heat through radiation or, more prohibitively, limit computing. To address these challenges, the team developed heat sinks that contain a wax-based phase change material that melts within the normal operating temperature range of the electronics. The melting wax is able to store energy more rapidly and keep the electronics cooler for longer.
"We're testing different duty cycles and cooling regimes with the fixed heat sinks that we've put up there," Clemon said. "The idea is for this to inform design and operating sequences for other electronics and computing in space."
The team deployed their test rig onboard a CubeSat, a miniaturized satellite comprised of cubic modules measuring 10 cm per side. The satellite launched in August 2024 (see its operational dashboard here ) with several payloads, including the heat sinks, as part of the Waratah Seed Mission . "We alternate our experiments with those of the other payloads," Clemon said.
The team's results thus far are promising—for one, the melting wax significantly increases the time that the electronics can operate within a safe temperature range. Furthermore, the microgravity environment does not impact the orientation of the wax on the heat sinks.
"We've developed some simplified models to predict the performance of these heat sinks that may provide a first direction for designers to test their designs against rather than having to build something and test it physically," Clemon said.
With more experiments planned, the team's explorations in space will continue.
"Our orbit is about 90 minutes, and because of that we have some sun exposure time and non-sun exposure time," Clemon explained. "There's an underlying heating profile from the sun itself, and we want to explore the effect of that on the computing time that's available for the electronics."
