Astronomers set up center to counter threat of satellite swarms

6th February, 2022.      //   Space Travel, Uncategorized  // 

A pass of the Starlink 4 train of satellites in a night sky.

Three years ago, astronomers were reeling from the launch of the first 60 satellites of SpaceX’s Starlink constellation, which aims to provide broadband internet access worldwide. The satellites left bright traces on astronomical images, posing “an existential threat to observation from the ground,” said astronomer Debra Elmegreen, president of the International Astronomical Union (IAU), at a briefing today. Without much coordination, different groups of astronomers scrambled to understand the problem and to mitigate it by working with satellite operators. But now, astronomers are getting organized about it.

IAU announced today it is setting up the Centre for the Protection of the Dark and Quiet Sky from Satellite Constellation Interference. The IAU center will coordinate efforts to study the impacts of the new swarms on astronomy, negotiate with their operators, and lobby for laws to protect the night skies, says center director, Piero Benvenuti of the University of Padua, a former IAU president. The center will begin operations on 1 April with funding for seven staff. Funding will come mostly from IAU and two partner institutions, the U.S. National Optical-Infrared Astronomy Research Laboratory (NOIRLab) and the Square Kilometre Array observatory.

At the start of this year, constellation operators had launched about 2800 satellites—mostly SpaceX but some from U.K.-based OneWeb—already overtaking the 2200 satellites that were active at the time of Starlink’s first launch. Those and other companies have sought approval for plans that would loft as many as 50,000 satellites into low-Earth orbit. “Hundreds will be visible to the eye on any night,” says NOIRLab’s Connie Walker, who will be co-director of the IAU center. “It will have a substantial impact on all telescope operations.”

Assessing the impact of future constellations is one goal for the center. Studies have already shown that survey telescopes with wide fields of view will be the worst affected. For instance, the Vera C. Rubin Observatory, due for first light in 2023, will have as many as one-third of its images ruined by satellite streaks during part of the night. Radio telescopes could also be affected by interference from radio downlinks that satellite constellations use to communicate with the ground.

A second task will be to work with industry to develop protocols for reducing reflections and tracking satellite positions so telescopes can avoid them. After Starlink’s debut, astronomers worked with SpaceX to reduce the satellites’ impact by installing “visors” that shade reflective surfaces. Benvenuti says astronomers are already in dialogue with two other operators—OneWeb and Amazon’s Project Kuiper. “We’re happy with what has happened so far,” he says. “The example they made should be followed by other companies.”

But astronomers don’t want to rely on companies’ goodwill. Another role for the center will be to create national and international laws and norms for what regulators allow in orbit. “We need to codify these good intentions, to have some backup,” says Richard Green of the University of Arizona’s Steward Observatory. “We’ll take a two-pronged approach: Cooperate and develop legislation to apply if necessary.” IAU and other bodies are working to convince the United Nations’s Committee on the Peaceful Uses of Outer Space of the need for legislation. “We are confident that we will have guidelines that will have to be followed by companies in the near future,” Benvenuti says. Cosmologist Aparna Venkatesan of the University of San Francisco says it would be good if there were laws in the United States and elsewhere that echoed the influential U.S. Clean Air Act: “Many of us dream of a Clean Skies Act.”

A last job for the center will be to alert and seek help from other affected groups, including amateur astronomers, astrotourism operators, and Indigenous communities that observe the sky in their cultural practices. Satellite constellations, says Jessica Heim, an expert in cultural astronomy at the University of Southern Queensland, “interrupt our relationship with the stars.”

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