The emitted radio waves from the Starlink satellites obscure the cosmos

While SpaceX's Starlink satellites enable internet access and cellular communications around the globe, they also pose a threat to radio astronomy, according to a new study.

In some wavelength ranges, the accidental leakage of electromagnetic radiation from the latest generation of satellites is more than 30 times brighter than emissions from previous versions, Cees Bassa, a radio astronomer at the Netherlands Institute for Radio Astronomy in Dwingeloo, and his colleagues report Sept. 18 Astronomy and astrophysics. Because the latest generation of Starlink satellites will orbit up to 100 kilometers lower than previous satellites, they will appear even brighter to ground-based telescopes. Overall, their brightness could easily obscure the observation of dimmer objects such as distant galaxies or stars.

Instead of collecting visible light, radio telescopes collect lower energy waves from sources that emit radiation at longer wavelengths. Bassa and his team used six radio telescopes at an observatory near Exloo, Netherlands, to characterize emissions from Starlink satellites during two-hour sessions in July. Although the satellites only passed through the telescopes' field of view for between 12 and 40 seconds, they were very bright: Compared to the faintest astronomical sources that can be observed with these telescopes, Starlink satellites are about 10 million times brighter, Bassa and his report Team noted.

And the problem is likely to get worse: SpaceX is launching about 40 second-generation Starlink satellites every week, the researchers note, with more than 6,000 already in orbit (SN: 03/03/23). Bassa and his colleagues have discovered that other companies' satellites can also be detected by radio telescopes, and they are working to measure these emissions as well.

Bassa and his colleagues hope that their continued observations will encourage developers of such satellites to redesign their equipment, if possible, to reduce unintentional radio emissions.