More than 14,000 satellites are circling the planet, and every bright hull can drag a streak across a telescope’s long exposure – a problem astronomers have watched build for years as launches accelerate. A team in the UK has now tested one of the blackest materials ever made as a fix, and the numbers look promising.
The answer they tested is Vantablack 310, an ultra-black coating made by Surrey NanoSystems, a University of Surrey spinout that co-authored the new study, published in Monthly Notices of the Royal Astronomical Society. In lab tests, surfaces coated with it bounced back only about 2 percent of the light that struck them. Think of it like the difference between a glossy car hood and a matte-black one: the light that comes off scatters diffusely instead of flashing, and flat reflections are far kinder to telescope images than sharp glints.
The team measured the coating’s reflectance across a range of lighting and viewing angles, then simulated how a coated craft would look from the ground. On the AB magnitude scale astronomers use, lower numbers mean brighter. At its most reflective – over snow rather than open ocean – the coated craft measured 6.7 to 7.0, a hair on the bright side of the magnitude 7 limit the International Astronomical Union recommends. Most simulated orbits came in fainter still, at 7.1 to 7.8. An uncoated SpaceX satellite the team also tested scored 3.7, dramatically brighter. “Under identical geometric and areal assumptions, the coated surface yields peak brightness values that are fainter than those reported for uncoated Starlink chassis, and comparable to or fainter than DarkSat and VisorSat variants,” the researchers write.
Under an electron microscope, the coating turns out to have “coral-like features with cavity-like depressions” – the physical structure that traps the light. It is a newer formulation, built to go on more easily and take more punishment than the original. The team is explicit about what it has not shown: “We emphasize that this study addresses optical performance only,” they write, and “Spacecraft-level thermal behavior, environmental durability, and system integration require dedicated thermal-vacuum testing and in-orbit validation and are therefore beyond the scope of this work.”
The next step is already scheduled. A CubeSat called Jovian-1, a student-led mission with teams at Surrey, Portsmouth and Southampton, will carry the coating into orbit so astronomers can measure its real-world brightness from the ground. Projections put as many as 60,000 satellites in orbit by 2030. “The night sky is one of humanity’s oldest windows into the Universe,” says lead author Astha Chaturvedi of the University of Surrey. “But it is becoming increasingly difficult to see things.”
The practical upshot: “Our results show that relatively simple material choices could make a meaningful difference to how satellites affect astronomical observations without requiring major changes to mission design,” Chaturvedi says. Noelia Noël, who leads Surrey’s wider Light Pollution and Sustainable Space initiative, sees the bigger picture: “What is encouraging about this research is that it moves us beyond simply identifying the problem and towards developing practical, evidence-based solutions.” The coating still has to survive the brutal environment of orbit – but if it does, the blackest paint ever made could help keep the oldest window we have worth looking through.
Sources
- Vantablack: World's Blackest Paint Could Solve A Major Problem For Astronomy : ScienceAlert
- Scientific Frontline: Vantablack 310: Satellite Light Pollution Solution
