Satellites in low orbit are sending out radio signals that block astronomy work

Low-earth orbit communication satellites are giving off radio signals that block astronomy work across various frequencies, according to a study published in the Monthly Notices of the Royal Astronomical Society. The study came out of a satellite radiation monitoring programme named SNIFFLES.

The Study

The researchers used the Mopra radio telescope and the Australia Telescope Compact Array to track satellites from the Starlink, OneWeb, and China's Guowang constellations. They tracked these satellites for nearly 376 hours starting in April 2024. Based on what they saw, the team sorted the radiation into three groups: intended, unwanted, and unintended. Intended transmissions involved direct-to-cell signals from Starlink satellites. Unwanted transmissions covered emissions from transmitters, including signals at multiples of the transmission frequency known as harmonics. Unintended radiation meant stray emissions coming from electronic parts like computers and power converters.

Specific Findings

The study found a signal from the OneWeb constellation at 1,613.19 megahertz that could interfere with telescopes studying hydroxyl ions in space. The team also spotted radiation at 2,700 Hz appearing in nearly 77% of observations from a certain version of Starlink satellites. Some signals were even 100-billion-times brighter than typical sources in space, which could easily overwhelm telescopes.

Context

Protecting the work of astronomers means operators will need to regulate both their licensed transmissions and stray radiation coming from onboard electronics. Experts suggest that applying existing international rules about radio transmissions through the atmosphere could help control these space emissions.