Astronomers designed the Square Kilometre Array Low (SKA-Low) over decades to detect neutral hydrogen signals from cosmic dawn—the first stars that flickered on roughly 13 billion years ago. Instead, they’re increasingly picking up electronic leakage from SpaceX’s Starlink satellites.
A research team from Curtin University analyzed approximately 76 million radio images collected over 29 days using the Engineering Development Array 2, a prototype SKA-Low station in Australia. The results, published in Astronomy & Astrophysics, reveal extensive contamination across the exact frequencies SKA-Low needs to operate.
Researchers catalogued 112,534 individual radio emissions from 1,806 unique Starlink satellites operating across 73–235 MHz. Some satellites emit periodic 13-kHz tones at roughly 137 MHz every 100 seconds. Critically, these aren’t scheduled transmissions that operators can plan around—they’re unpredictable hardware leakage that researchers cannot model or subtract from their observations.
The signal strength disparity is stark: Starlink’s leaked emissions reach up to 10⁶ Jy/beam, while the ancient hydrogen signals SKA-Low is designed to detect require sensitivity near 10⁻⁵ Jy. According to Curtin University’s Steven Tingay, the leaked emissions are comparable to the brightest natural radio sources in the sky. Starlink signals reportedly measure around 10,000 times stronger than the cosmic signals SKA-Low needs to detect. In some frequency ranges, up to 30% of images contained Starlink interference. Additionally, emissions were found inside two ITU-protected astronomy bands—73–74.6 MHz and 150.05–153 MHz—where such signals aren’t supposed to exist at all.
International regulatory frameworks create a significant gap: the International Telecommunication Union protects certain radio astronomy bands from intentional transmissions, but unintended electromagnetic radiation—hardware leakage—largely falls outside that protection. Current rules don’t technically cover accidental emissions, even when they contaminate protected spectrum.
SpaceX has engaged on related issues before. Satellite visors reduced optical brightness, and an NSF coordination agreement addressed higher-frequency radio bands. However, beam management doesn’t solve low-frequency hardware leakage. The company is reportedly open to dialogue on future hardware changes, and researchers shared their findings with SpaceX.
Algorithmic mitigation is being explored but remains “embryonic,” potentially requiring computing power that rivals the science processing itself. Engineering fixes—similar to design changes that addressed optical brightness—remain the most viable solution, though the Starlink constellation already exceeds 6,000 satellites.
Key facts
- Curtin University researchers detected 112,534 radio emissions from 1,806 unique Starlink satellites over 29 days using a SKA-Low prototype in Australia
- Starlink signals measure approximately 10,000 times stronger than the ancient hydrogen signals SKA-Low is designed to detect
- Emissions were found in two ITU-protected radio astronomy bands where they should not exist
- Up to 30% of radio images at some frequencies contained Starlink interference
- Current international regulations do not cover unintended electromagnetic radiation from satellites, leaving a regulatory gap