A study from astronomers has found that Starlink satellites can interfere with radio telescopes by leaking excess radiation. On Wednesday, astronomers in Europe publicized the study, warning that second-generation Starlink satellites can “emit up to 32 times brighter unintended radio waves” compared to first-generation satellites used from 2019 to 2021. The effects can potentially “blind” the radio telescopes, derailing astronomy research, according to ASTRON, the Netherlands Institute for Radio Astronomy. “This research highlights the necessity for stricter regulations surrounding satellite unintended radiation to preserve the sanctity of radio astronomical observations,” the institute said. ASTRON also runs LOFAR, a large radio telescope based in Europe. In July, astronomers decided to examine the impact of Starlink on radio telescopes by using LOFAR to take a pair of one-hour observations of the night sky in certain radio bands.
(ASTRON)
The study found 147 and then 97 Starlink satellites passing through the two observations. Standing out were the second-generation “V2-Mini” and “direct-to-cell” Starlink satellites, which emitted a higher level of unintended electromagnetic radiation over a broader frequency range compared to the first-generation satellites. Specifically, the second-gen satellites can be up to 32 times brighter than the first-gen, but only about 5 times brighter compared to the “v1.5” Starlink satellites, which began launching in 2021. ASTRON has also published a video clip, showing how the Starlink satellites can appear in real-time over a radio telescope. The presence of Starlink is subtle, appearing more like twinkling stars streaking through the night sky.
Still, ASTRON says the unintended electromagnetic radiation can appear about 10 million times brighter than the faintest stars observed over LOFAR, making it harder for radio telescopes to detect far-off astronomical objects across the universe. “This difference is similar to the faintest stars visible to the naked eye and the brightness of the full Moon,” said the astronomer Cees Bassa, lead author of the study. The institute is also concerned given that SpaceX and other companies plan on launching tens of thousands of low-Earth orbiting satellites, increasing the interference risk. In addition, SpaceX wants to orbit more Starlink satellites closer to Earth while amplifying their signal output. “Given that low-frequency radio telescopes are primarily built for their large fields of view, the large numbers of satellites from current and future satellite constellations may lead to the situation that one or more satellites are present in the telescope’s field of view at any given time,” the study from ASTRON also says.
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Distances and power flux density measurements of Starlink satellites that passed through the observations. (ASTRON)
It’s not the first time scientists have sounded the alarms about Starlink’s impact on radio astronomy. Back in May, they began urging the US Federal Communications Commission to regulate SpaceX’s Starlink satellites from interfering with radio telescope equipment.Although SpaceX didn’t immediately respond to a request for comment, the company has already been cooperating with the scientists on preventing Starlink satellites from disrupting astronomy-related research. This has included working with observatories in the US to prevent Starlink satellites from emitting radio waves toward the “eye” of radio telescopes, which can blind them. In the meantime, ASTRON is hopeful it can collaborate with SpaceX to address the excess radiation from the Starlink satellites. “We have the solutions for this symbiosis in space as well – we just need the regulators to support us, and the industry to meet us half-way,” said ASTRON scientific director Jessica Dempsey. “Without mitigations, very soon the only constellations we will see will be human-made.”
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About Michael Kan
Senior Reporter
I’ve been working as a journalist for over 15 years—I got my start as a schools and cities reporter in Kansas City and joined PCMag in 2017.
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