IAU “deeply concerned” about satellite mega-constellations

A time exposure taken near Carson National Forrest in New Mexico shows Starlink satellite trails shortly after launch. Image: RAS/M. Lewinsky/Creative Commons Attribution 2.0

The International Astronomical Union has selected the Square Kilometre Array Organisation, or SKAO, in the UK and NOIRLab in the United States as co-hosts of the newly formed IAU Centre for the Protection of the Dark and Quiet Sky from Satellite Constellation Interference.

The convoluted name refers to increasing concern across the astronomical community about the impact of so-called “mega-constellations” of small internet and data relay satellites like those operated by SpaceX’s Starlink and OneWeb and fleets proposed by Amazon and other entities.

“The International Astronomical Union is deeply concerned about the increasing number of launched and planned satellite constellations in mainly low-Earth orbits,” the organisation said in a statement. “The IAU embraces the principle of a dark and radio-quiet sky, not only as essential to advancing our understanding of the Universe of which we are a part, but also for the cultural heritage of all humanity and for the protection of nocturnal wildlife.”

The IAU proposed the centre in June 2021. Its mission is “to coordinate efforts and unify voices across the global astronomical community with regard to the protection of the dark and quiet sky from satellite constellation interference.”

The Royal Astronomical Society says as many as 100,000 spacecraft are expected to populate low-Earth orbit by the end of the decade. SpaceX alone has now launched more than 2,000 Starlink internet satellites and has U.S. regulatory approval to launch thousands more as it builds out a global space-based broadband service.

SpaceX has been responsive to astronomers’ concerns, altering the designs of their spacecraft to minimise their visibility. But the sheer number of planned satellites poses a major challenge.

“The most obvious impact is the appearance of many more trails across images made with optical observatories, both on the ground and in space, which require time-consuming and expensive mitigation with software or repeat observations, and in some cases render data useless,” the RAS says.

Radio astronomy also is threatened, researchers say. Satellite downlink signals are up to 10 trillion times more powerful than signals from astronomical sources.

“The Society is arguing for changes to the space licensing regime that ensure our science is protected, at a national and global level, and strongly supported the creation of the new IAU centre,” the RAS said.