Once completed, the Square Kilometer Array Observatory (SKAO) will be the world’s most sensitive and powerful radio telescope, as long as SpaceX’s Starlink satellites do not impair its view.

Private companies have begun launching dozens of “constellations” of communications satellites into low- and medium-Earth orbits with the goal of covering the entire world with high-speed Internet access, real-time surface monitoring and more. Leading this responsibility is SpaceX, which has launched more than 4,600 Starlink satellites into space so far and plans to place 42,000 satellites into orbit in the next decade.

Other companies, such as Amazon, plan to follow their own constellations. While global high-speed Internet access is certainly a good thing, these constellations have implications for astronomy. Astronomers around the world have already warned that Starlink is starting to disrupt their ground-based observations and that the glow from all the satellites will make the night sky brighter around the world.

Radio astronomers face similar challenges posed by Starlink. First, the Netherlands-based LOFAR collaboration found evidence that Starlink’s broadcasts were jamming signals from some astronomical targets. And now the team of astronomers who helped develop SKAO have conducted preliminary tests and come up with some disturbing conclusions, and they’ve published them in a paper on the arXiv preprint database.

The researchers used a network of radio antennas called Engineering Development Array 2 (EDA2) located in the deserts of Western Australia. EDA2 is a testing platform that will help develop the full version of SKAO, which is expected to be completed in 2028. Combining facilities in Western Australia and South Africa, SKAO will be the world’s leading radio telescope whose primary mission will be to map neutral hydrogen. A cosmological period known as the Cosmic Dawn was the period that filled our universe before the first stars went up in flames.

Researchers were able to detect Starlink emissions with EDA2, and these emissions were much brighter than future SKAO astronomical targets. It is noteworthy that they found two sources of pollution. Only one signal was expected: the usual broadcasts that satellites send to each other on Earth. But another type was unintentional: radio signals produced by the electronics of individual satellites. EDA2 and the future SKAO are so sensitive that they can easily detect such unintentional emissions.

The authors of the article were careful to point out that some international governing bodies reserve some radio frequencies for astronomical use only, and signals from Starlink satellites are not in these protected bands. Therefore, SpaceX is not violating any international agreements regarding intentional or unintentional radio emissions.