Ultra-Black Coating Could Mitigate Light Pollution Caused by Satellites

There is no doubt that the night sky is changing. Satellites are regularly passing overhead, creating bright light trails that interfere with stargazing and backyard astronomy. These satellites also pose a significant threat to natural ecosystems. The problem stems from the design of the satellites themselves. Many satellites include large solar arrays that reflect sunlight. This reflection creates an artificial, diffuse glow that brightens the night sky. As a result, the light from natural objects, such as the Moon, the planets, and distant stars, becomes difficult to see.

With 1.7 million satellites expected to be launched into orbit in the coming years, the situation may worsen. Some experts worry that the problem may reach a point where children look up and wonder why the Moon and the few remaining natural objects visible are not streaking across the sky. To mitigate this problem, a team of researchers from the University of Surrey has developed a new ultra-black coating material for satellites. This new material could drastically reduce the amount of light the satellites reflect.

The presence of satellites in the night sky is something humanity has come to expect. This expectation began ever since the launch of Sputnik 1 in 1958. Sunlight reflected from these early satellites could create bright streaks and flares. At the best of times, these light patterns can be visually appealing to observers on Earth. However, the number of active satellites in Low Earth Orbit (LEO) has risen rapidly. At the time of the study, there were approximately 20,000 active satellites, and this number continued to grow. There are increasing concerns that these streaks could interfere with telescope observations. They also pose challenges for large-scale surveys of the night sky.

Some major scientific projects are already affected by this issue. An example is the Legacy Survey of Space and Time (LSST). This survey is currently underway at the Vera C. Rubin Observatory. Among its many objectives, this ten-year survey will create an inventory of the Solar System. This inventory will include Near-Earth Asteroids (NEAs), objects in the Main Asteroid Belt, and many more types of celestial bodies. Another major objective is to explore the transient optical sky. Scientists want to study objects that move or change in brightness. This task will be very difficult with so many streaks and bright spots filling the sky.

In their study, which appeared in the Monthly Notices of the Royal Astronomical Society, the researchers demonstrated how Vantablack® 310 could significantly reduce light pollution. Vantablack® 310 is an ultra-black coating developed by a company spun off from the University of Surrey. The company is called Surrey NanoSystems. The technology grew out of work involving Professor Ravi Silva. He is the director of the Advanced Technology Institute (ATI) at the University of Surrey and the head of its NanoElectronics Center. He was not directly associated with this specific study.

With development and commercialization provided by Surrey NanoSystems, the team rigorously tested this material. They did this as part of a broader effort to develop and evaluate future coatings. The goal was to find satellite surface designs that would protect astronomical observations and the night sky. James Whitfield was the Applications Scientist at Surrey NanoSystems and a co-author of the study. He stated that satellite constellations offer enormous benefits to society. However, their growing brightness presents a serious challenge for ground-based astronomy. He noted that Vantablack® 310 combines ultra-black performance across a wide range of viewing angles. It also has the durability needed for low-Earth orbit. He said the team is proud to work with the University of Surrey to help protect the night sky while supporting innovation in satellite technology.

In computer simulations, the coating proved effective at making satellite surfaces significantly fainter. The results showed that the satellites became faint enough to be close to the International Astronomical Union's recommended limit. The findings suggest that ultra-black coatings could provide a practical way to reduce the impact of future satellites on astronomy. It offers a way to protect the night sky from excessive light pollution.

Astha Chaturvedi is the lead author of the study. She is a postgraduate researcher at the University of Surrey. She said the night sky is one of humanity's oldest windows into the Universe. However, it is becoming increasingly difficult to see things clearly. She explained that their results show relatively simple material choices could make a meaningful difference. These choices can reduce how satellites affect astronomical observations. Importantly, this solution does not require major changes to mission design. This makes the approach much easier to implement.

Study co-author Dr. Noelia Noël is a Senior Lecturer in Astrophysics at the University of Surrey. She said space is becoming increasingly crowded. This creates challenges not only for astronomers but for everyone who values an unspoilt night sky. She said what is encouraging about this research is that it moves us beyond simply identifying the problem. It moves us toward developing practical, evidence-based solutions. As an astrophysicist at Surrey, she is particularly proud that a potential solution to this astronomical challenge has emerged from pioneering materials research at their own university.

The team is now preparing for an in-orbit demonstration. This demonstration will involve the student-led Jovian-1 CubeSat mission. This is a cooperative satellite program involving the universities of Surrey, Portsmouth, and Southampton. The demonstration will test the coating's performance in space. It will also determine whether changes in brightness can be measured from the ground. This real-world test is crucial for validating the simulation results.

Astha Chaturvedi, the lead author on the study, will present their research at the 2026 United Nations Workshop on Dark and Quiet Skies in Vienna. She indicated that their paper is fundamentally about addressing an important challenge for astronomy. They are using an evidence-based approach to solve the problem. The research shows how the astronomical community is working together with engineers and industry. They are developing realistic, scientifically grounded mitigation strategies. These strategies are designed to benefit both space activities and the protection of the night sky. This collaboration highlights a growing global effort to balance technological progress with the preservation of our natural environment.