Key facts
- A new gold and silver nanoparticle coating has been developed to prevent the multipactor effect in satellites.
- The multipactor effect is an avalanche of electrons that can cause irreversible damage to satellite equipment.
- The nanoparticle coating reduces secondary electron emission by approximately 30% compared to the traditional Alodine treatment.
- The coating's cut-off energy threshold improves by up to 300% in some configurations.
- The technology is covered by a European patent application filed in July 2025 by CSIC and Nanostine.
A team from the Spanish National Research Council (CSIC), in collaboration with its spin-off Nanostine and supported by the European Space Agency (ESA), has developed an innovative coating for satellites designed to prevent the multipactor effect. This phenomenon, an avalanche of electrons occurring in a vacuum within components like antennas, can lead to irreparable damage to satellite systems and has been a concern for the ESA for over four decades.
The new coating utilizes gold and silver nanoparticles, applied at the nanometric scale to create a rough surface. This approach, unlike previous attempts focusing on micrometric structures, significantly reduces secondary electron emission, which triggers the damaging chain reaction. Tests conducted in ESA-accredited laboratories show that this nanoparticle coating reduces secondary electron emission by approximately 30% compared to Alodine, the chromium-based compound traditionally used for protection. Furthermore, the cut-off energy threshold, where a material begins generating more electrons than it receives, sees an improvement of up to 300% in some configurations.
Beyond its superior technical performance, the nanoparticle coating offers environmental and health benefits, as Alodine is harmful to handle and the environment, prompting European authorities to push for its ban. The new material has undergone rigorous six-month ageing tests and thermal treatments at 150°C, simulating conditions experienced by satellites, and maintained higher performance than freshly applied Alodine even after these stresses.
The technology has secured a joint European patent application filed in July 2025. Nanostine is set to lead the commercialization efforts, primarily targeting the aerospace sector. While the results are promising, researchers caution that bringing a new coating into actual space use typically requires about a decade of further testing and validation, though ESA has expressed satisfaction with the solution.