Radio astronomers are raising alarm bells over SpaceX’s Starlink cellular technology

SpaceX and AST SpaceMobile are working to bring satellite connectivity to smartphones, but scientists say the technology risks disrupting radio astronomy.

“The proposed satellites with a direct connection to the cell would effectively eliminate the existence of radio quiet zones, which would significantly reduce the efficiency of existing radio telescopes,” says Catherine Lovekin, associate professor of physics at Mount Allison University in Canada.

Lovekin is among scientists and groups urging the FCC to regulate cellular satellites from interfering with radio astronomy equipment. Satellites effectively act as cell towers in low Earth orbit, routing radio signals and Internet data to phones on the ground.

SpaceX and AST SpaceMobile plan to operate hundreds of direct satellites to help carriers like T-Mobile and AT&T serve users in dead zones. But a growing number of astronomers and scientists say the constant radio interference from so many satellites poses an “existential threat” to radio astronomy.

Bluewalker Satellite (Credit: AST Spacemobile)

In its letter to the FCC, the American Astronomical Society states that scientists have made important discoveries through radio astronomy precisely because they had “clear access to the broad radio spectrum, either through the establishment of a radio quiet zone or the placement of observatories in remote locations. .

“This will no longer be possible with constant interference from overhead satellite transmissions. Without access across the wider spectrum, astronomical research will only be possible on a small slice of the spectrum allocated specifically for this purpose, greatly limiting the potential for discovery,” he added. warned the company, which has over 7,700 members.

The astronomers are speaking out after the FCC approved new rules in March that allow satellite providers to beam connectivity to consumer phones. But the commission said it was also well aware of concerns about interference, including radio astronomy. That’s because a month earlier, the National Science Foundation, an independent federal agency, released a white paper dedicated to studying the matter.

“Preliminary NSF analysis indicates significant impacts on radio astronomy systems,” the white paper noted, citing “power levels and all-sky visibility” from such satellite systems. The paper also warns that radio signals from satellites “may even damage radio astronomy hardware” if the satellite’s transmitter passes directly in front of the radio astronomy receiver.

“While it is possible that the severity of damage to radio astronomy can be mitigated by careful coordination and selection of the absolute minimum bandwidths and power levels necessary for any permitted SCS, radio astronomy will be adversely affected under any implementation scenario,” the NSF went on to say.

(Photo by Paul Hennessy/NurPhoto via Getty Images)

SpaceX and AST SpaceMobile did not immediately respond to a request for comment, though both say they are working with the astronomy community on mitigation to avoid disrupting scientific research. But the key question remains whether cellular satellite technology can coexist with radio astronomy, or whether one must come at the expense of the other.

Meanwhile, scientists lobbying the FCC are demanding that companies like SpaceX and AST SpaceMobile demonstrate that their technology won’t interfere with radio astronomy before receiving commercial approval. This includes demonstrating “their ability to operate without directly illuminating, disabling or damaging receivers at radio astronomy observatories,” the National Radio Astronomy Observatory said in its own filing.

This is not the first time that astronomers have expressed concern about large constellations of satellites. In recent years, they have also criticized satellites from SpaceX and AST SpaceMobile for photobombing their observations or emitting too much light into the night sky.

The FCC has not yet authorized SpaceX or AST SpaceMobile to commercially operate their mobile satellite systems. Scientists and astronomy groups are lobbying the FCC after it opened a public comment period on its new rules for cellular satellite coverage, which also seek to minimize the risks of interference.