Researchers at the University of Surrey in the United Kingdom have tested a new ultra-black coating that could significantly reduce the brightness of satellites in low Earth orbit, offering a potential solution to the growing problem of light pollution from satellite constellations. The study, published last week in the Monthly Notices of the Royal Astronomical Society, demonstrates how the coating, known commercially as Vantablack 310, could help protect astronomical observations from the increasing number of spacecraft planned for launch.
With current proposals calling for more than 1.7 million satellites to be placed into orbit, astronomers worldwide have been urgently seeking ways to minimize the impact of these objects on night-sky observations. The reflective surfaces of satellites create bright trails and flares that interfere with telescope observations and wide-field sky surveys, making it more difficult to detect faint objects such as asteroids, distant galaxies, and other important astronomical phenomena.
Developed by Surrey NanoSystems, a spin-off company from the University of Surrey, Vantablack 310 is made from one of the darkest materials in the world—a polysiloxane-based substance with a siloxane backbone structure. The coating reflects only about two percent of incident light, and the small amount of light it does reflect is scattered more diffusely, reducing the bright flashes commonly produced by reflective satellite surfaces.
To assess the coating's effectiveness, the research team measured how Vantablack 310 reflects light under a range of different illumination and observation conditions. They then used these laboratory measurements to simulate how a satellite surface coated with the material would appear when viewed from Earth. The simulations showed that the coating could make spacecraft surfaces significantly dimmer, bringing their brightness close to the limit of AB magnitude 7 recommended by the International Astronomical Union (IAU) for the protection of astronomical observations.
The study's lead author, Astha Chaturvedi, emphasized the importance of evidence-based approaches to addressing the challenge. “Our study aims to tackle a major challenge for astronomy through an evidence-based approach,” Chaturvedi said. “It demonstrates how the astronomical community is collaborating with engineers and industry to develop realistic and scientifically grounded mitigation strategies, for the benefit of both space activities and the protection of the night sky.”
The findings suggest that relatively simple material choices could make a significant difference in how satellites affect astronomical data collection, without requiring major changes in mission design. The team is now preparing for an in-orbit demonstration aboard the Jovian-1 CubeSat mission, a student-led satellite program involving the universities of Surrey, Portsmouth, and Southampton. This demonstration will verify both the coating's performance in the space environment and the ability to measure the resulting brightness change from the ground.
The research has also gained international attention. Chaturvedi was invited to present the work at the United Nations workshop on dark and quiet skies, held in Vienna last December. The workshop focused on international efforts to preserve the night sky for scientific and cultural purposes, highlighting the growing global concern over satellite light pollution.
The study, titled “Reducing the impact of satellite brightness for astronomy: laboratory characterization and simulations,” was co-authored by A. Chaturvedi, N. E. D. Noël, K. Clifford, J. Whitfield, and K. A. Ryden. It appears in the Monthly Notices of the Royal Astronomical Society.