Ultrafast-laser-structured components cool better in space

Researchers at the Fraunhofer Heinrich-Hertz-Institut (HHI) in Berlin have found that satellite components and rocket nozzles structured with ultrashort-pulsed lasers showed improved heat dissipation when tested in space.

Etching micron-scale cones into aluminum and titanium material specimens is said to have resulted in a massive increase in thermal emissivity while remaining stable at high temperatures.

The team explains that because space is a vacuum, heat cannot be transferred to the surroundings by thermal conduction. “This poses a problem for any type of space-capable electronics, which can quickly overheat under these conditions,” they point out. “The only way to dissipate heat in space is through radiation into space.”

Research group leader Eike Hübner added: “Because smooth metal surfaces like the aluminum outer walls of satellites, the outer surfaces of rocket nozzles, or the cases for power electronics are very poor at dissipating heat, we use a laser to roughen them.

“The rough textured surface essentially acts like a radiator and radiates heat very effectively. We can functionalize all geometries, including complex shapes such as curved surfaces.”

Nanosecond laser switch

After using femtosecond lasers to roughen various metal surfaces, Hübner and colleagues found that the thermal emissivity increased from roughly 10 per cent for bare untreated metal to close to 100 per cent.

Textured surfaces also promise to cut launch costs, as the launch weight of carrier rockets is somewhat reduced by eliminating the paint coatings typically used to improve thermal radiation.

Several laser-structured aluminum and titanium specimens fabricated by the Fraunhofer HHI team have been in space for testing since December 2024. In a collaboration with the European Space Agency (ESA) and space engineering experts at Azimut Space GmbH, the high thermal-emissivity surfaces were mounted on the outer hull of the International Space Station (ISS) in the direction of flight as radiative heat sinks for evaluation under real-world conditions.

Those metal specimens are now on their way back to Earth. “The analysis and examination for material aging, potential damage and changes in thermal radiation are therefore still pending,” says Hübner.

Despite that, Hübner and colleagues Hanan Al-Haddar and Ahmad Abdalwareth are already looking to commercialize their approach via a new startup company called Dythalis, primarily targeting manufacturers of satellites and thrusters.

Because the femtosecond laser process used thus far is relatively costly, they plan to use a more affordable and robust nanosecond laser approach that can generate comparable milled structures in metal surfaces under a reactive gas atmosphere such as pure oxygen.

“Although this will slow down the process and we will only achieve a thermal emissivity of roughly 85 per cent, it will significantly reduce investment costs,” said Hübner.

Next week HHI researchers will present electronic boxes and nozzles structured using femtosecond lasers at the joint Fraunhofer Space booth during the ILA 2026 aerospace trade fair, which is taking place in Berlin.