The scene, as far as a screen could hold one: on a Thursday in early February 2022, at a virtual press conference, the largest global organization of astronomers unveiled a new institution built for a single fight. The timing was not subtle. That same day SpaceX launched 49 more Starlink satellites, pushing the internet constellation past 2,000 machines, already by far the biggest satellite network in the sky. The new body, the “Centre for the Protection of the Dark and Quiet Sky from Satellite Constellation Interference”, came from the International Astronomical Union, the crowd of professionals from more than 90 countries best known to the public for demoting Pluto in 2006, and it would sit in two places at once: the National Science Foundation’s NOIRLab in Tucson, Arizona, and the Square Kilometer Array Observatory in Manchester, England. At the lectern for the launch was the union’s president, an American astronomer from Vassar College named Debra Elmegreen.
Her sentence that day became the movement’s shorthand. “Optical and infrared trails and radio transmission by satellite constellations pose an existential threat to astronomical observations from the ground”, Elmegreen said. The center’s first director, Piero Benvenuti of the University of Padova, framed the shift plainly: “In the past, the main source of interference was the light pollution from the ground”, he said. For a century the enemy had been sprawl: city glare drowning telescopes, radio stations and mobile networks jamming the quiet bands. Now, with batch after batch of satellites going up, the astronomers were looking at a sky that glowed back, and counting: Starlink alone served more than 100,000 users, and counting Starlink with Amazon’s Project Kuiper, China’s Starnet and Canada’s Telesat, orbit could hold 100,000 satellites within a few years.
On the ground, Elmegreen’s own record explains why she was the one saying it. A child of South Bend, Indiana, born in 1952, she reached Princeton University at a moment when the doors were just opening, graduating in 1975 as the first woman to earn an astrophysics degree there; Harvard followed, with a master’s and a doctorate, and in 1979 she became the first female post-doctoral researcher the Carnegie Observatories had ever taken on. Since 1985 she taught at Vassar, holding the Maria Mitchell Chair and rising to head its astronomy department; she led the American Astronomical Society from 2010 until 2012, served the International Astronomical Union as vice president and president-elect, and held its presidency from 2021 to 2024. The credentials are not decorative. She studies how stars are born and how galaxies change, work that needs exactly the dark, quiet sky she spent her presidency defending, across more than 200 scientific papers and a 1997 textbook.
The evidence had already arrived in the images. A team using the Zwicky Transient Facility at Palomar Observatory found that 18 percent of its twilight images taken in 2021 contained satellite streaks, against less than half a percent two years earlier, and lead author Przemek Mróz of the University of Warsaw was matter-of-fact about why: “Given that we are one of the largest field-of-view instruments and operate a significant fraction of the time in twilight, pointed as close to the sun as we are comfortable, it is not surprising that many ZTF images have a satellite streak”. He expected nearly all of their twilight images to carry streaks by the end of the decade, and satellite light to bedevil the Vera Rubin Observatory in Chile, whose first light was planned for the following year. Aaron Boley of the University of British Columbia, who with colleagues had estimated that at about 65,000 satellites the machines would make up “about one in 10 lights one can see in the night sky”, ticked through the costs: lost asteroid warning time, “This leads to the possibility of confusion, data loss, and ultimately a loss of warning time”, and, on the radio side, the plain verdict that “In 10 years, if there are no changes, we’ll have a very congested region in low Earth orbit. It results in a constant struggle to understand what’s real, what’s a natural phenomenon, and what’s not”.
The center opened with four hubs. One, SatHub, would pool trail images from professional and amateur telescopes while coaxing companies to share their data; another would talk to industry about building less reflective satellites; a third would draft national and international policy; the fourth, community engagement, reached outward, and its head, Jessica Heim of the University of Southern Queensland, carried the sharpest line of the day from the indigenous members of her working group, who see the constellations as a new form of colonization: “Satellites literally interrupt our relationship with the stars and ceremonial ways of connecting with them, and if light pollution is erasing indigenous stories, these satellites are rewriting them”. Behind the hubs sat two years of workshops and reports, SATCON 1 and 2 in the United States and the international Dark and Quiet Skies series, each arguing that far more needed doing, in a window the SATCON 2 report called “narrow and closing”.
The record shows what a presidency can and cannot do. Elmegreen’s term ran to 2024; the launches did not pause for it, and the sky kept brightening on schedule. What changed was that the astronomers stopped complaining privately and built an institution with a name as long as the problem, cohosted an ocean apart, pointed at once at the companies and the regulators. Her word for the threat was existential, which in astronomy is not a metaphor. The stars, as she reminded everyone, are the oldest dataset there is, and by nightfall on any given evening, more of the lights crossing them were made in factories.
