Satellites leak noise that interferes with telescopes and GPS. Here’s how to fix it
The problem is about to get much worse, with millions more satellites planned in coming years.
In the past decade, the number of operational satellites orbiting Earth has surged from around 2,000 to over 15,000, with many more planned. While the issue of space debris has garnered considerable attention, another problem remains largely unnoticed: the radio noise emitted by these satellites is interfering with telescopes and GPS systems. However, this issue may be solvable if action is taken promptly.
Radio telescopes are essential for studying the early universe, with the ability to detect signals from shortly after the Big Bang and pinpoint distant galaxies. These telescopes are also critical for anchoring technologies like GPS, which is used for positioning, navigation, and timing on Earth. Australia has a rich history in radio astronomy, with pioneering research conducted at Dover Heights in Sydney in the 1940s.
Today, Australia is home to world-leading telescopes such as the MWA, ASKAP, and the world's largest low-frequency radio telescope, SKA-Low, which is being built in Western Australia.
Unfortunately, these valuable telescopes face interference from satellite radio emissions. While satellite operators already take steps to shield electronics to prevent interference during launch, the leakage continues once the satellites are in orbit. The International Telecommunication Union sets regulations for radio spectrum use by both astronomers and commercial entities, based on simulations of what a satellite is designed to transmit. However, these regulations do not account for unintended radio energy.
CSIRO-led research in New South Wales demonstrated that satellite emissions exceed international limits between 50% and 70% of the time, far surpassing the acceptable 2% threshold. In Australia, measurements from Western Australia revealed that Starlink satellites are already spoiling over half (59%) of GPS geodetic measurements at the current satellite numbers. With only a fraction of the planned satellite count, every GPS measurement would be lost.
To address this issue, satellite operators must shield electronics over a broader range of radio frequencies and reduce the amount of radio energy that leaks. The window of opportunity to fix these problems before the satellite population explodes is currently open. Failure to act could result in the demise of radio astronomy and threaten essential technologies like GPS.
A crucial first step is implementing a system to routinely monitor satellite radio interference, ensuring the development of a more robust evidence base for policy decisions, standards work, and enforcement. Australia, with its existing telescopes, heritage, and clear skies, is well-positioned to take the lead in this crucial effort.
Written by urgent.news from The Conversation AU's reporting — not their text. Machine-written — may contain errors; check the original before relying on it.
