„Coral traps“ for light
A team of astrophysicists from the University of Surrey in the United Kingdom believes they have found a practical solution.
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Their research shows that this problem can be solved by “Vantablack 310” – a special version of one of the darkest materials in the world, adapted for spacecraft.
The biggest drawback of artificial satellites (for example, SpaceX’s Starlink) is their shiny metal body, which acts like a huge mirror, reflecting sunlight back to Earth.
The scientists’ idea is simple: to coat these satellites with a “Vantablack 310” coating. In laboratory tests, this material demonstrated incredible results – it absorbs up to 98% of the light falling on it, which means that only 2 percent is reflected back.
Using an electron microscope, the researchers examined the structure of this coating and found that it creates miniature shapes resembling corals with deep cavities.
Light photons entering these “coral traps” simply get lost among the microscopic structures, turn into heat, and can no longer escape back into space.
An advantage over current SpaceX attempts
To assess the technology’s effectiveness, the researchers applied physics models, testing the reflections of the coated satellite in different orbital trajectories, such as flying over snowy areas or over the ocean.
The results were compared with the recommendations of the International Astronomical Union and current SpaceX attempts to reduce reflections.
A typical SpaceX satellite exhibited very high brightness – 3.7 points on the astronomical brightness scale. The lower the number, the brighter the object in the sky.
Astronomers recommend that satellite brightness in the sky should not exceed 7 points, making them as hard to see with the naked eye as possible.
Even under the most unfavorable conditions, the satellite coated with the black material reached a brightness of 6.7–7.0 points, and in many simulated orbits, the indicators dropped to safe 7.1–7.8 points.
This means that this coating performed better or was fully comparable to the special darkened versions developed by SpaceX, without requiring changes to the spacecraft design itself.
Test in real space
The scientists emphasize that this study covered only optical usefulness. The space environment is ruthless – there are extreme temperature differences, vacuum, and cosmic radiation, so the material must be extremely durable.
The next big step is already planned: a small satellite will be coated with “Vantablack 310” in the upcoming “Jovian-1” mission.
This will allow scientists to measure the real brightness of the satellite directly from Earth observatories as it orbits.
According to the researchers, it is encouraging that this technology allows moving from problem identification to real, fact-based solutions.
If humanity becomes increasingly dependent on satellite systems in the future, it should not cost us the ability to explore the night sky.
