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SpaceX was the biggest enemy of the astronomers when it started launching Starlink internet satellites.
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But SpaceX worked with scientists to reduce the brightness of the satellites in telescope images.
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Some of SpaceX’s solutions sort of work. Other mega-satellite enterprises, like Amazon, are taking notice.
NEW ORLEANS – When SpaceX launched its first Starlink satellites, astronomers around the world went there and the company quickly became a villain in the skies.
“I felt as if life as an astronomer and a lover of the night sky would never be the same,” said astronomer James Lowenthal New York Times in 2019.
As the bright trail of satellites climbed through space, ascending to their target orbit in May 2019, people standing outside could see them clear as day, drifting overhead circling the Earth.
For some, it seemed like the end of astronomy. “If there are lots and lots of bright objects moving in the sky, it makes our job very complicated,” Lowenthal told the Times.
But for rural populations, including in developing countries, that lack reliable internet, Starlink could make a big difference as SpaceX aims to blanket the Earth in high-speed broadband internet, courtesy from more than 10,000 satellites.
However, Starlink satellites – now more than 5,000 in number – are streaking across astronomers’ views of the cosmos, destroying their data. Not even some telescopes in space are safe. A study last year found that about one-third of Hubble Space Telescope images could be destroyed by satellites by 2030.
SpaceX is leading the change
SpaceX is not alone in this effort; it was just the first company to get huge batches of bright spacecraft off the ground. At least a dozen companies, as well as the Chinese government, are planning to launch their own mega-fleet of satellites.
Many astronomers view the new business of internet satellite constellations as an existential threat. But of all the companies trying to claim this new frontier, SpaceX has mollified some of its critics by listening to them, working with them, and trying to darken its satellites.
“We’re making progress now,” Jonathan McDowell, an astronomer who has been one of Starlink’s most outspoken critics, told Business Insider at an American Astronomical Society conference in New Orleans.
McDowell and other astronomers were meeting with representatives of the satellite industry to discuss efforts to keep the skies dark and radio-quiet.
No current SpaceX representatives participated in the session. Still, Starlink’s experimental solutions dominated the conversation—perhaps because it’s the only company trying the solutions suggested by astronomers.
“To me the focus is not just on the alarm call, it’s on the path to coexistence,” Patricia Cooper, a satellite industry consultant who was SpaceX’s vice president of government affairs for satellites, told the assembled astronomers . “Not surprisingly, we haven’t solved the problem in four and a half years.”
SpaceX has tried black paint, a sun visor, and now ‘mirror film’
SpaceX threw a bunch of spaghetti at the wall to dim the light from its satellites, and some things have stuck.
In 2020, about six months after that first bright Starlink trail streaked through the skies, SpaceX took its first stab at the problem by essentially painting the satellites black.
That kind of helped. The satellites were not as bright, but they were still very bright.
Later that year, SpaceX tried using solar mirrors to prevent sunlight from hitting the bottom of the satellites, where it can reflect back to Earth and make them bright.
That worked. The shielded satellites were about one-third as bright as those launched without visors. But they were still bright enough to mess with astronomers’ data. The visors were a regular feature for many Starlink satellites until SpaceX added laser communications. The visors blocked the lasers, so they had to go.
Now SpaceX is looking at a “mirror film” that could further reduce brightness on the next generation of Starlink. However, those satellites are much larger than the old ones, “so it’s kind of canceled,” said McDowell.
“I don’t think everything is a villain or a hero here,” he said.
SpaceX developed its solutions through meetings with astronomers, including the world’s first conference on satellite brightness. In 2022, the International Astronomical Union formalized this ongoing collaboration as the Center for the Protection of the Dark and Quiet Sky from Interstellar Satellite Crossing — CPS, for short.
SpaceX has even adopted an operational tweak suggested by astronomers – pointing the satellites’ solar panels away from the sun as they pass over the line between night and day. That’s when they appear on the horizon, and they do the most damage to telescopes on Earth. Astronomers help give less sun to the solar panels at this time, but it means less energy for the satellite.
“That’s a real, substantial mitigation that they’ve done,” McDowell said. “They’re really making a lot of money doing that. So we’re grateful for that.”
“Whether the other companies will do it remains to be seen,” he said.
Amazon and other companies may follow SpaceX’s lead
Amazon and a small Earth imaging company called Planet Labs are following SpaceX’s lead.
Chris Hofer, international team leader for Amazon’s Project Kuiper internet satellites, told the astronomers in New Orleans that SpaceX’s Starlink tinkering was helpful.
Since joining CPS, Hofer said Amazon has started improving its solar panels and looking into solar shades.
Hofer and Kristina Barkume, from Earth imaging satellite company Planet, said they would be following SpaceX’s new mirror tests with interest.
“Those innovations help us,” Barkume told Business Insider.
Although it appears that some companies are paying lip service to the satellite problem, or even spending money on it, it probably won’t go away.
In the coming years thousands of satellites could be crowding the Earth’s orbit. Regardless of how bright they are or not, they are bound to disrupt astronomy. Scientists will have to find ways to see the gaps between satellites, no matter how small or convenient those windows in space become.
Read the original article on Business Insider
