Scientists and engineers are raising alarms about the growing radio interference from satellite constellations. This issue is sparking calls for stricter performance standards from operators.
For astronomers, the interference from satellites in Low Earth Orbit is a long-standing problem. Many satellites, like SpaceX’s Starlink, can disrupt both optical and radio observations due to their signals clashing with scientific research bands.
In a recent chat with The Register, Tudor Williams, the CTO of Filtronic, a company specializing in high-frequency RF communications, highlighted the main concerns. He explained that the interference primarily stems from satellite-to-ground communications rather than satellite-to-satellite connections.
Williams pointed out that poorly designed antennas can cause signals to spread unintentionally. This overlap of communication and observation bands is especially frustrating for radio astronomers trying to capture clear signals from the universe.
Historically, the issue was not well understood during initial satellite testing, leading to gaps in regulations. Williams suggested that regulations may have been too lenient when satellites first launched, saying, “As we gather more data, we can create stricter guard bands and regulations.” A guard band is a buffer in the radio spectrum that prevents interference from different channels.
The challenge lies in the design flaws of antennas, which can unintentionally send strong signals in various directions. Williams remarked, “Designers do their best, but errors can occur, leading to leaks in the spectrum. Authorities will need to define acceptable levels of interference.”
As the number of satellites grows, astronomers face increased interference. Yet, Williams believes that as the technology evolves and satellite operators collaborate with scientists and regulators, improvements can be made. For existing satellites, retrofitting is tough but tweaking waveforms could help lessen interference. “Optimizing waveforms, potentially with AI, could reduce distortion even with current hardware,” he said.
He highlighted that there’s a mutual understanding among satellite operators and scientists about these challenges. Operators are under pressure to manage their spectrum effectively to maintain their licenses. “We’re looking for a balance between scientific missions and broadband communications,” Williams noted.
With satellites like Starlink designed for shorter lifespans—around five years—there’s a chance for hardware changes as regulations tighten. Williams pondered, “Will it cost more to improve signal control? Yes, likely, because complicated designs can push up manufacturing costs.”
The rapid increase in satellite constellations has led to unexpected levels of radio frequency interference, not just visual pollution from the night sky. Williams concluded that as feedback filters back into standards bodies, satellite operators will have to enhance their performance standards moving forward.
