The problem arrived in a neat row of moving lights. In May 2019, SpaceX lifted 60 satellites, each about 500 pounds, into low orbit, and within days amateur skywatchers were photographing them: a line of craft shining as brightly as Polaris, the North Star. Astronomers, who had known the launch was coming, reacted with something close to alarm, because those 60 were only the first instalment of a planned mega-constellation called Starlink, meant to connect the planet to the internet.
The brightness was the headline worry. Each satellite carries a solar panel that gathers sunlight and reflects it back down; oriented just right, a craft can briefly flare to rival Sirius, the brightest star in the sky. Elon Musk offered assurances that the satellites would be visible only in the hours around dusk and dawn, and only faintly, but early images led many scientists to question that, with some estimating naked-eye visibility through summer nights. Every pass through a long-exposure image leaves a bright streak that typically ruins the frame. One estimate had the 8.4-meter Large Synoptic Survey Telescope, then under construction on a Chilean mountaintop, facing a Starlink craft in every couple of images taken during the first hours of twilight. “This has the potential to change what a natural sky looks like,” said Tyler Nordgren, an astronomer who promotes night skies. Ronald Drimmel of the Turin Astrophysical Observatory put it more bluntly: “We’re really at that point where we have to assess what we’re going to do”.
Light is only half of it. The satellites also emit radio waves, and radio astronomers build their dishes in remote quiet zones precisely to escape such noise. Starlink’s plan to operate on two frequency ranges that scientists use to map gas across the universe drew particular concern. “If those frequency channels become inaccessible, it’s extremely limiting to what we can learn about the early universe,” said Caitlin Casey of the University of Texas at Austin. The worries were not new: Iridium’s phone-network satellites made their own flashes in the 1990s.
Seven years on, the constellation is no longer a fear but a fact. Proposed in 2015 and filed with the Federal Communications Commission in 2016 as a 4,425-satellite system, later expanded toward nearly 12,000, Starlink has grown past 7,000 deployed satellites serving more than one hundred countries, with newer craft adding laser links between them.
The 2019 debate never closed. Amazon, Telesat and OneWeb lined up behind their own space-internet plans, and the Outer Space Treaty of 1967, with its vision of space as the province of all mankind, sits uneasily beside a sky filling with commercial light. What began as a bright train over the world’s backyards is now the default night sky for a generation of stargazers.
Sources
- Starlink Satellite Constellation – eoPortal
- After SpaceX Starlink Launch, a Fear of Satellites That Outnumber All Visible Stars – The New York Times
