The Vera Rubin Observatory satellite interference problem has become a growing concern for astronomers preparing to open one of the world’s most advanced telescopes. Originally conceived in the 1990s and now located atop Chile’s Cerro Pachón, the observatory was expected to deliver pristine, sweeping views of the southern sky. However, the rise of satellite megaconstellations may now compromise its mission.
When construction began in 2015, astronomers had no idea the sky would soon change so drastically. In 2019, SpaceX launched the first Starlink satellites, and what started as a small constellation has rapidly expanded. With satellites orbiting just 340 miles (550 kilometers) above Earth, they now interfere with sensitive telescopes, including Vera Rubin, which features an exceptionally wide field of view.
Designed to capture the entire sky every three nights, the telescope’s 26-foot (8.4-meter) mirror and 3,200-megapixel camera make it incredibly sensitive. Unfortunately, this also means it is highly susceptible to light trails from satellites. According to astronomer Meredith Rawls of the University of Washington, these streaks are already a concern. “Everything that makes this telescope amazing also makes it vulnerable to these satellites,” she explained.
After launch, satellites appear especially bright. A 2019 image taken from a neighboring telescope revealed 19 Starlink satellites streaking through the sky shortly after deployment. Vera Rubin’s team now expects as much as 40% of its images to be affected by such streaks. This could translate to over 4 million degraded images during the observatory’s 10-year mission.
Rawls has worked with the observatory team since 2016. Initially, she focused on refining image quality and identifying rare celestial events. But satellite interference forced her to change direction. Now, she develops algorithms to detect and flag streaks, using multiple exposures to identify and eliminate passing satellites from datasets.
Although the situation is frustrating, Rawls remains optimistic. She describes satellite trails as “bugs on a windshield”—obstructive, but not catastrophic. Each camera detector holds 4,000 pixels, and even when streaks appear, only a small fraction of pixels are affected.
Still, the scale of the issue is growing fast. SpaceX’s Starlink constellation may reach 42,000 satellites. Other players, including Amazon’s Kuiper and China’s Guowang, Qianfan, and Geespace, plan to add tens of thousands more. This could push the total number of active satellites to over 100,000 in the next decade.
Some incidents show how serious the problem can become. In 2021, a group of astronomers mistakenly believed they had witnessed a stellar explosion. Later analysis revealed the light source was a piece of space debris reflecting sunlight, not a supernova. Such false readings could pollute data and skew results.
Beyond Starlink, other satellite systems also pose a challenge. AST SpaceMobile has launched BlueBird satellites, massive 693-square-foot antennas designed to deliver direct-to-phone 5G service. These units are so bright that Vera Rubin’s team must plan observations to avoid them. As Rawls noted, “You don’t want to waste time pointing the telescope at a sky full of glare.”
Solutions are emerging, though progress remains slow. SpaceX has attempted to reduce satellite brightness, but results have been limited. The International Astronomical Union recommends satellites stay below magnitude 7 in brightness, making them invisible to the naked eye. However, most Starlink satellites measure between magnitudes 3 and 5, making them far too visible for sensitive equipment.
Fortunately, new technology may help. A U.K. company, Surrey NanoSystems, has introduced an ultra-dark space paint. It is durable, space-tested, and capable of reducing reflectivity to meet IAU guidelines. If satellite manufacturers adopt such coatings, the impact on ground-based astronomy could shrink dramatically.
The true extent of the Vera Rubin Observatory satellite interference remains to be seen. However, scientists hope cooperation between satellite companies and astronomers can keep the sky open for discovery. Rawls remains focused on solutions, not setbacks. “We’re not giving up. We’re adapting.”
