“I felt as if life as an astronomer and a lover of the night sky would never be the same,” astronomer James Lowenthal told the New York Times in 2019.
As the bright trail of satellites climbed through space, ascending to their target orbit in May 2019, people just standing outside could see them clear as day, zipping overhead as they circled Earth.
To some, it seemed to herald the end of astronomy. “If there are lots and lots of bright moving objects in the sky, it tremendously complicates our job,” Lowenthal told the Times.
But for rural populations, including in developing countries, that lack reliable internet, Starlink could make a huge difference since SpaceX aims to blanket the Earth in high-speed broadband internet, courtesy of more than 10,000 satellites.
Nonetheless, Starlink satellites — now more than 5,000 strong — are streaking across astronomers’ views of the cosmos, ruining their data. Some telescopes are not safe in space. Just last year a study found that about one-third of the Hubble Space Telescope’s images could be ruined by satellites by 2030.
SpaceX leads the way for change
SpaceX isn’t alone in this endeavor; 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-fleets of satellites.
Many astronomers view the budding business of internet-satellite constellations as an existential threat. SpaceX, out of the many companies trying to stake a claim on this new frontier has managed to calm some critics, by working with them and darkening its satellites.
“Now we’re making progress,” Jonathan McDowell, an astronomer who has been one of the most outspoken of Starlink’s critics, told Business Insider at a conference of the American Astronomical Society in New Orleans.
McDowell and other astronomers were meeting with representatives from the satellite industry to discuss efforts to keep the skies dark and radio-quiet.
A current SpaceX representative did not attend the meeting. Starlink was the company that dominated discussion, perhaps because they were the only ones who had tried the solutions suggested by astronomers.
“For me the focus is not on the call to alarm only, it’s on the path to coexistence,” Patricia Cooper, a satellite-industry consultant who was formerly VP of SpaceX’s government affairs for satellites, told the assembled astronomers. “Not surprisingly, we didn’t solve the problem in four and a half years.”
SpaceX has tried black paint, sun visors, and now ‘mirror film’
SpaceX has thrown a handful of spaghetti at the wall to dim its satellites’ shine, and a few things have stuck.
In 2020, about six months after that first bright Starlink trail glided through the skies, SpaceX lobbed its first noodle at the problem by essentially painting a bunch of the satellites black.
This helped a little. They were brighter, but still not enough.
Later that year, SpaceX tried using sun visors to block sunlight from hitting the bottom side of the satellites, where it can reflect back to Earth and make them appear bright.
That worked. They were only about one third as bright as satellites 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. They had to be removed because the visors were blocking lasers.
Now SpaceX is looking into a “mirror film” that could further reduce brightness on its next Starlink generation. However, those satellites are much bigger than the old ones, “so it kind of cancels out,” McDowell said.
“I do not think that there is a villain and a hero in this story,” McDowell added.
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 Centre for the Protection of the Dark and Quiet Sky from Satellite Constellation Interference — CPS, for short.
SpaceX has even adopted an operational tweak that astronomers suggested — pointing the satellites’ solar panels away from the sun as they pass over the line between night and day. This is when the sun’s rays are at their highest on Earth, and can be detrimental to telescopes. Giving the solar panels less sun at this time helps astronomers, but means less energy for the satellite.
“That’s real, substantial mitigation that they’ve done,” McDowell said. They’re taking a big financial hit. So we appreciate that.”
“If the other companies will do it remains to be seen,” he added.
Amazon and other companies may follow SpaceX’s lead
Amazon and a small Earth-imaging company called Planet Labs are both following SpaceX’s lead.
Chris Hofer, international team lead for Amazon’s Project Kuiper internet satellites, told the astronomers in New Orleans that SpaceX’s Starlink tinkering has been helpful.
Since joining CPS, Hofer said Amazon has begun improving its solar panels and looking into sun shades.
Both Hofer and Kristina Barkume, of the Earth-imaging satellite company Planet, said they would be following SpaceX’s new mirror-film tests with interest.
“Those innovations help us,” Barkume told Business Insider.
Though a few companies seem to be paying lip service to, or even throwing money at, the bright-satellite problem, it probably won’t go away.
The coming years could see tens of thousands of satellites crowding Earth’s orbit. No matter how bright they are or aren’t, they will almost certainly interfere with astronomy. Scientists must find a way to peer through gaps in the satellites to see the universe, no matter how small and fleeting these windows may be.