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NSF and SpaceX reach agreement to reduce Starlink effects on astronomy

Gemini laser guide star
The coordination agreement between NSF and SpaceX includes several conditions intended to reduce the effects of Starlink satellites on astronomy, including SpaceX agreeing not to require observatories to turn off lasers used for adaptive optics systems when Starlink satellites pass overhead. Credit: Gemini Observatory/AURA image by Joy Pollard

SEATTLE — The National Science Foundation has reached an agreement with SpaceX to mitigate the effects of the company’s second-generation Starlink satellites on astronomy, even as another organization goes to court to block the constellation’s deployment.

NSF, which funds operations of several major observatories, announced Jan. 10 that is had completed an astronomy coordination agreement with SpaceX regarding its Gen2 Starlink constellation. The Federal Communications Commission granted a license Dec. 2 to allow SpaceX to deploy a quarter of that 30,000-satellite system while deferring consideration of the rest of the constellation.

That coordination agreement was a condition of the Gen2 FCC license, said Richard Green, an astronomer at the University of Arizona who has led efforts to address how satellite constellations could interfere with astronomy. “That’s what we wanted them to do, and that’s what they did,” he said during a session on satellite constellations at the 241st Meeting of the American Astronomical Society (AAS) Jan. 10. He noted SpaceX had voluntarily worked with the NSF on that agreement just before the FCC issued the license.

As part of that agreement, SpaceX said it would continue to work to dim its satellites to no brighter than the 7th magnitude, making them invisible to the naked eye and reducing, but not eliminating, their effect on sensitive astronomical instruments. SpaceX also agreed not to transmit when their satellites pass over major radio observatories.

SpaceX also agreed to remove its satellites from a database called the “Laser Clearinghouse” that is used by astronomers to determine when they have to turn off lasers used as artificial guide stars for adaptive optics systems. Such lasers can dazzle or damage optics on satellites. SpaceX determined the lasers posed no risk to the spacecraft, and NSF said that by removing the satellites from the database, astronomers will be saved “multiple closures” as Starlink satellites pass overhead.

The agreement is voluntary, since beyond the FCC requirement for such an agreement in the Gen2 Starlink license there is no law or policy requiring SpaceX or other satellite operators to mitigate the effects of their constellation on astronomy. “Policy is slow,” Green said. “The progress that we make in the short term relies entirely on the voluntary cooperation with industry, for which SpaceX has really been a leader in showing the way for other corporations.”

Starlink is not the only constellation astronomers are worried about. The launch in September of BlueWalker 3, a technology demonstration satellite for AST SpaceMobile’s constellation of direct-to-smartphone satellites has raised concerns, in part because of its large antenna made the spacecraft very bright.

“We’ve had conversations with the company,” said Connie Walker, co-director of the International Astronomical Union’s Center for the Protection of the Dark and Quiet Sky from Satellite Constellation Interference, at the AAS session. “AST SpaceMobile is very amenable to trying some mitigation solutions.”

One organization, though, is going to court to block Starlink’s deployment. The International Dark-Sky Association (IDA) filed an appeal of FCC’s order licensing the Starlink Gen 2 system with the U.S. Court of Appeals for the District of Columbia Dec. 29. The organization, which represents astronomers concerned about the effects of light pollution on the night sky, argued the FCC failed to follow environmental law in approving the constellation.

“It is unprecedented for IDA to resort to the court system to resolve disputes. But in this case, we felt compelled to act,” the organization said in a Jan. 6 statement. Given the size of Starlink and other planned constellations by other companies, “it is critical that federal agencies responsible for making decisions on the future of the night sky – an essential element of the human environment – follow existing laws.”

IDA argues in a court filing that its members “face a series of harms” from the FCC’s decision to award the Starlink license, including adverse impacts on amateur and professional astronomy and “a diminishment in the enjoyment of the dark sky.”

The basis for its appeal is that the FCC violated the National Environmental Policy Act (NEPA) by awarding the license. The FCC stated in its order that it concluded an environmental review under NEPA for Starlink’s effects on astronomy was not warranted because SpaceX’s mitigation efforts, including the NSF coordination agreement, were sufficient.

Charles Mudd, the lawyer representing the IDA in its appeal of FCC’s license, said at the AAS conference session that interpretations of NEPA and corresponding regulations are broad enough to include effects from satellites. “There are definitions that would implicitly include regulating Earth’s orbital space as part of the environment,” he said.

The IDA is not the first organization to challenge an FCC Starlink license. Viasat appealed an earlier FCC order amending SpaceX’s first-generation Starlink license, allowing more satellites in lower orbits, on the grounds that FCC failed to follow NEPA. A federal court dismissed the appeal in August, ruling that Viasat lacked standing to appeal.

Mudd said that others are also appealing the FCC license for Starlink Gen2, and that the various cases will be consolidated. According to court filings, Dish Network appealed the FCC license Jan. 3 on the grounds that the Gen2 Starlink satellites would create “unacceptable interference” for Dish’s direct-to-home satellite television signals in the 12-gigahertz band.

Jeff Foust writes about space policy, commercial space, and related topics for SpaceNews. He earned a Ph.D. in planetary sciences from the Massachusetts Institute of Technology and a bachelor’s degree...