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U.K. buys stake in satellite company that could spoil astronomy

OneWeb plans to launch as many as 42,000 satellites to an orbit that could harm astronomy.

NASA/Kim Shiflett

By Daniel Clery

When OneWeb filed for bankruptcy protection in March, astronomers breathed a sigh of relief. The company planned to launch thousands of internet-providing satellites into low-Earth orbit, where their reflections could disrupt the observations of ground-based telescopes. But now, the company has risen from the grave with the announcement today that the U.K. government and the Indian cellphone operator Bharti Global have successfully bid to rescue OneWeb with a $1 billion investment.

The revived company now plans an even larger constellation of up to 42,000 satellites, at an altitude of 1200 kilometers—the worst possible outcome for astronomers. At that altitude, satellites will leave bright trails across telescope images all through the night, effectively ruining the observations of survey telescopes such as the 8-meter Vera C. Rubin Observatory, under construction in Chile. “It’s the stuff at 1000 kilometers that is the real killer for astronomy,” says Mark McCaughrean of the European Space Agency, speaking at a briefing organized by the European Astronomical Society (EAS). “Engagement [with astronomers] has to happen and it has to happen now.”

Astronomers first became concerned about such “megaconstellations” last year, when the launch company SpaceX lofted the first batch of its Starlink satellites. The aim of the project is to provide internet access in areas hard to reach with fiber-optic cables. The satellites, launched 60 at a time in a single rocket, proved to be highly visible in the sky, to the alarm of astronomers. The company has now launched 540 Starlink satellites—part of an initial goal of 1584—and aims to provide a service in the United States and Canada before the end of the year.

Early on, astronomers began working with SpaceX to mitigate the impact of its satellites. In a January launch, one satellite was covered with an antireflective coating (dubbed Darksat), and in June, one satellite carried a sunshade to stop reflections (Visorsat). Although Darksat partially reduced the satellite’s visibility, it wasn’t enough to satisfy astronomers. Visorsat has yet to reach its operational altitude so, Olivier Hainaut of the European Southern Observatory told the EAS briefing, “we don’t know yet” how bright it will appear. But McCaughrean says Starlink’s next launch will be populated entirely with Visorsats.

OneWeb is one of several other companies chasing Starlink with similar goals. Astronomers had only limited interactions with the company before it filed for Chapter 11 protection in March with 74 satellites launched toward an initial goal of 650. While new owners were being sought, OneWeb applied for permission to expand its constellation to 42,000.

The U.K. government said in a statement today that its acquisition of OneWeb will “contribute to the government’s plan to join the first rank of space nations.” Initial reports suggested the government wanted to transform the constellation into a navigation system akin to GPS, because with Brexit, the United Kingdom will no longer be a governing member of Europe’s Galileo navigation system. But there is no mention of navigation plans in today’s statement.

The rescue of OneWeb still has political and legal hurdles to overcome, but Robert Massey of the Royal Astronomical Society told the EAS briefing: “I would hope the government uses its leverage to ensure OneWeb are a good partner and engages with the scientific community.” He adds, “It’s hard to believe they didn’t know.”

Source: Science Mag