Astronomers want to save the dark sky from satellite swarms

Last Thursday, on The same day that SpaceX launched 49 Starlink Internet Relay Satellites – joining more than 2,000 others on the world’s largest satellite network – the world’s largest astronomers’ organization launched a new institution to save the night sky from satellite brightness and radio interference. .

The new Center for the Protection of Dark and Quiet Skies from Satellite Disturbances comes from the International Astronomical Union, which includes professional astronomers from more than 90 countries, including those who famously (or sadly) lowered Pluto in 2006. The center will have two leading : NOIRLab of the National Science Foundation – named after optical and infrared astronomy, not noir fiction – in Tucson, Arizona, and the radio astronomy-focused observatory Square Kilometer Array in Manchester, England. The Center will coordinate research and advocacy to reduce the effects of light and radio interference on scientific observations.

“In the past, the main source of interference was light pollution from the earth,” said Piero Benvenuti, an honorary astronomer at the University of Padua in Italy and the center’s first director, at a virtual news conference last Thursday. Astronomers have long worried about scattered cities with ubiquitous outside lights obstructing their view as they try to peer into the sky with their telescopes, as well as radio stations and communications signals, including cell phones and wireless networks, interfering with their radio observations.

Now astronomers’ worries have changed and they are looking up. “Optical and infrared pathways and radio transmission from satellite constellations pose an existential threat to astronomical observations from Earth,” said Debra Elmegrin, president of the IAU and astronomer at Vassar College, at the same event.

In just a few years, after many launches of batches of satellites, SpaceX’s Starlink has become the largest artificial constellation in the sky. It now provides broadband internet access to more than 100,000 users, with more to come. Within a few years, including other satellite megastars such as Amazon Project Kuiper, China’s Starnet / GW and Canada’s Telesat, there could be up to 100,000 satellites in orbit, each emitting some light and sending radio signals.

Benvenuti and his colleagues are worried about how difficult it will be to pursue space science if satellites end up bombarding astronomers’ images. The creation of the new IAU center signals that maintaining the dark skies and tackling the effects of these constellations have already become international priorities. In the last two years, many of the leading astronomers at the new center have already organized online seminars producing detailed reports, including SATCON 1 and 2 in the US and the international Dark and Quiet Skies 1 and 2. Each report argues that much more needs to be done. do to deal with the effects of thousands of satellites in low Earth orbit; the window of opportunity is “narrow and closing”, as stated in the SATCON 2 report.

The new center includes four groups or “hubs”. One, called SatHub, will collect data from professional and amateur astronomers, including satellite imagery, while encouraging companies to share their data so astronomers can better minimize the effects of satellites on their work. Another will communicate with industry experts in the hope that companies will build their new satellites to be less reflective and avoid the radio frequencies that telescopes use. Another center will focus on making national and international policy recommendations. The latter will coordinate community engagement by collaborating with local communities, environmentalists, astro-tourism groups, the planetarium community and others with an interest in reducing light pollution and preserving the dark and quiet skies for all.