SpaceX’s Starlink Internet satellites “leak” so much radiation that it harms radio astronomy, scientists say

The hum of onboard electronics that power SpaceX’s Starlink satellites could be disrupting radio astronomy observations, according to a new study.

Experts have long warned about how astronomy suffers from megaconstellations of satellites in low Earth orbit such as SpaceX‘S Stellar connection. The stripes those satellites leave the observations of telescopes even in the most remote locations in the astronomical images. The reflection of sunlight from these satellites could lead to a unwanted brightening of the night sky even in areas far from urban light pollution. And the radio waves used by these satellites to carry out their communications could hinder the observations of sensitive radio telescopes.

But a new, unexpected source of scientific clutter has now emerged thanks to a new study by researchers using the Low Frequency Array (LOFAR) telescope in the Netherlands: radiation from on-board electronics inside Starlink satellites.

Related: Megaconstellations like SpaceX’s Starlink could interfere with world’s largest radio telescope’s search for life

LOFAR is a network of over 40 radio masts spread across the Netherlands, Germany and some other European countries. The telescope can detect the longer wavelengths of radiation emitted by objects in the cosmos. However, as it turns out, radio frequencies similar to what LOFAR is designed to detect are also being emitted unintentionally by Starlink satellites. In the new study, researchers described the detection of this unwanted low-frequency radio hum from nearly 50 Starlink spacecraft.

“With LOFAR, we detected radiation between 110 and 188 MHz from 47 of the 68 satellites that were observed,” Cees Bassa, an astronomer at the Netherlands Institute of Radio Astronomy (ASTRON), which manages the LOFAR array, and a co-ha said the author of the recent article in a statement. “This frequency range includes a protected band between 150.05 and 153 MHz specifically assigned to radio astronomy by the International Telecommunication Union.”

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The discovery worries next-generation large-scale radio observatories, such as the Square Kilometer Array Observatory (SKAO), currently under construction at two remote sites in Australia and South Africa. To maximize the telescope’s ability to detect even the weakest signals, regulators have placed quiet zones around sites where the use of cell phones, terrestrial TV or radio is not permitted. Starlink satellite constellations (and other Internet broadcasts), however, can travel freely over those places and, due to their low-altitude observations, are disturbing.

The ASTRON team added in their statement that SpaceX does not violate any rules as this type of radiation from satellites is not regulated by any guidelines, unlike that from ground-based devices.

“This study represents the latest effort to better understand the impact of satellite constellations on radio astronomy,” said lead author of the study and SKAO spectrum manager Federico Di Vruno. “Previous Dark and Quiet Skies workshops have theorized about this radiation, our observations confirm that it is measurable.”

The researchers further modeled the impact of this ‘unintentional’ radiation from a larger number of satellites. The simulations showed that the side effects would become more pronounced with the size of the constellation.

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“Our simulations show that the larger the constellation, the more important this effect becomes as the radiation from all the satellites adds up,” said co-author Benjamin Winkel of the Max-Planck-Institute for Radio Astronomy (MPIfR) in Germany . “This makes us concerned not only about the existing constellations but even more about the planned ones. And also about the absence of a clear regulation that protects the radio astronomy bands from unwanted radiation”.

The authors added that SpaceX is collaborating with astronomers to find solutions that allow the constellation and astronomy to coexist without negative impacts.

SpaceX has already launched more than 4,000 Starlink satellites, according to astrophysicist and satellite tracker Jonathan McDowell. The company already has regulatory approval to deploy 12,000 broadband communications satellites and has filed for approval to launch an additional 30,000 Starlink aircraft.

I study was published in the journal Astronomy & Astrophysics on Wednesday 5 July.