After a two-month gap, SpaceX has resumed launching batches of dozens of satellites in its gambit to blanket Earth with high-speed internet access.
The satellites are a new "VisorSat" variety to make them less shiny to the ground and especially to astronomers' telescopes. But researchers say the spacecraft's experimental new feature, while helpful, won't fully solve problems posed by the existence of Starlink itself (or other planned thousands-strong satellite fleets, for that matter).
SpaceX, founded by Elon Musk, calls its internet project Starlink, and may deploy tens of thousands of the broadband internet-beaming satellites into low-Earth orbit. On Friday at 1:12 am ET, one of the company's Falcon 9 rockets launched a new batch of them, along with two Earth-imaging spacecraft built by BlackSky Global.
SpaceX fitted all 57 of its desk-sized Starlink satellites with a new feature: sun visors or shades.
The visors should deploy after launch and block sunlight from reflecting off the satellites' surfaces – glare that makes Starlink spacecraft appear as bright, moving trails in the night sky that can photobomb telescope observations, blot out faint astronomical objects, and even hinder searches for killer asteroids.
The visors will probably make the satellites less bright, but it won't stop them from interfering with astronomy, says astronomer Jonathan McDowell.
"If you figure out where to put the visors, you should be able to really cut down those reflections. And that will make the satellites no longer naked-eye objects, which is good," he told Business Insider in June. "It won't, probably, make them so faint that they won't be a problem for professional astronomers."
SpaceX did not immediately respond to a request for comment.
An illustration of the Starlink satellite. (Space X)
Astronomers fear that SpaceX's bright satellites could outshine the stars
After SpaceX launched its first set of Starlink satellites in May 2019, many astronomers were alarmed by how bright the new objects were. In the days after the launch, people across the world spotted the train of satellites, like a line of twinkling stars.
"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 November.
"If there are lots and lots of bright moving objects in the sky, it tremendously complicates our job," Lowenthal added. "It potentially threatens the science of astronomy itself."
Telescopes on Earth that look for distant, dim objects could pick up these false stars and ruin astronomers' data. A single satellite can create a continuous streak of light across a telescope's long-exposure images of the sky, blocking the objects astronomers want to study.
"It takes just a couple seconds for the satellite to cross the telescope's field of view, but we take really long exposures with our cameras. So in that couple of seconds, a whole 10- or 15-minute exposure is ruined," McDowell said.
The satellites can especially affect telescopes that observe close to the horizon near dawn – the kind of observations that help astronomers track asteroids flying close to Earth.
SpaceX is sharing Starlink's orbital-path data with astronomers so that they can plan their telescope observations around the satellites' movements. Briefly shutting off the camera as the satellite passes overhead can save a long-exposure image.
To date, SpaceX has flown nearly 600 Starlink spacecraft to orbit – the most of any satellite operator. But Musk's grand ambitions could make it practically impossible for astronomers to avoid the fast-moving satellites.
SpaceX already has permission to launch nearly 12,000 satellites, and last year sought additional clearance to put up to a total of 42,000 satellites into orbit. And that's not counting other providers' plans.
"If they're coming over all the time, then knowing when they're coming over isn't helpful," McDowell said. Even now, he added, sometimes astronomers can't avoid the photobombers.
It's not yet clear how well a VisorSat works
It's unclear how effective the SpaceX's new visors will be, though the company launched an experimental "VisorSat" to test the concept on June 3. SpaceX has yet to report the results of that test.
"We're still waiting for the satellite to reach its operational orbit," Youmei Zhou, an integration and test engineer for SpaceX's Crew Dragon spaceship, said during a live broadcast of the launch early Friday morning.
Launching a whole fleet of visor-equipped satellites without widely sharing, or possibly knowing, the results of the experimental spacecraft visor seems like "a gutsy move" to McDowell.
"I think what it reflects is that they have much more confidence now that they understand the sources of the problem," he said.
The company doesn't expect earlier, visor-free Starlink satellites to complete their five-year life span, Patricia Cooper, SpaceX's vice president of satellite government relations, told Spaceflight Now in May. That means that, in a few years, the brightest satellites may no longer appear in the sky.
Satellite constellations pose larger problems that visors can't fix
The Starlink fleet caught astronomers' attention for how bright it was, but it revealed a much larger problem: The skies could soon be swarming with false stars.
SpaceX isn't the only company building a massive fleet of satellites. Companies like Amazon and OneWeb have similar aspirations to establish their own fleets and rake in billions of dollars each year.
"If OneWeb goes ahead and launches its proposed constellation without mitigation, that is going to have very severe impacts on ground-based astronomy to the point that, for at least four months out of the year, it's going to be pretty impossible to do most observations," McDowell said.
"You might as well just shut the observatory down for the summer months, because there's going to be so many satellites screwing up your data."
Mitigating solar reflections also goes only so far. Astronomers also worry about invisible wavelengths of light that stand to compromise other forms of astronomy.
The Federal Communications Commission, which authorizes the flight and use of internet-beaming satellites in the US, says preventing disruption to astronomy is "not a condition" for licensing – so SpaceX is pursuing solutions on its own accord. Sources known to Business Insider also say Amazon's Kuiper satellite-internet project is working with astronomers to reduce those satellites' impact.
But SpaceX and others have yet to announce potential harm-reduction measures for radiowaves the satellites will broadcast, or for the infrared light they emit by producing heat. Both can interfere with telescopes on Earth that observe the skies using radio or infrared.
"We're in a new phase of space utilization. It's a new space industrial revolution, things are different, and astronomy's going to be affected," McDowell said.
"We just have to make sure we're part of the conversation so we can keep it down to the 'pain in the neck' level and not the 'give up and go home' level."
Dave Mosher contributed reporting.
This article was originally published by Business Insider.
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