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Astronomers are working to make sure large satellite constellations don’t forever change the night sky

Furthest along in space-based internet plan SpaceX working with astronomers to mitigate impacts

ORLANDO, Fla. – By the end of the summer SpaceX had successfully launched nearly 700 satellites, known as the Starlink constellation, as part of CEO Elon Musk’s plan to create a space-based internet using a network of, eventually, up to 42,000 satellites.

The concept is that the satellites will provide internet to anywhere in the world, even remote areas.

But SpaceX isn’t the only company with grand plans of providing the internet this way. Amazon, OneWeb and Samsung are also looking to get in the internet game-- SpaceX just happens to be the furthest along. The company also has an advantage over their competitors, they provide their own ride to space for the satellites with the reusable Falcon 9 rocket.

Starlink satellites fly in an elliptical orbit around Earth and when sunlight reflects off the solar panels on the spacecraft people down on Earth can see the bright lights floating two-by-two in a string in the night sky. The sight can be awe-inspiring and confusing to some.

“You have these really, fairly large satellites comparatively to other satellites up there right now. And they’re highly reflective,” astronomer Derek Demeter said. “So if you’re putting in thousands 10s of thousands of these satellites, what’s going to happen is as they pass over in the angle of the sun, they’re going to light up, they’re going to get very bright, they’re going to be as bright as a star.”

Demeter is the director at the Emil Buehler Perpetual Trust Planetarium at Seminole State College. He recently had a personal encounter with these bright, shiny satellites while he was trying to view Comet NEOwise this summer. He was using long-exposures to try and photograph the rare, bright comet passing Earth.

“I was noticing these large trails. I’m like, ‘Oh my goodness, this is, this is Starlink.’ It was actually my first experience, personal experience, with seeing these constellation trails,” Demeter said. “You saw one go through your field of view. And then you saw another one go through the field of view. And then another one followed after that, and then another one. And it just felt like a train. It felt like it just never ended.”

Demeter made the photo below using multiple images and stacking them together, showing the Starlink streaks and the comet.

A composite image of Starlink satellite trails across an image of Comet NEOWise taken in Central Florida by astronomer Derek Demeter in July 2020. (Image credit: Derek Demeter.)
A composite image of Starlink satellite trails across an image of Comet NEOWise taken in Central Florida by astronomer Derek Demeter in July 2020. (Image credit: Derek Demeter.) (Derek Demeter)

Our view of the night sky has been changing ever since the light bulb was invented.

The more light sources we turned on -- from street lamps to bright lights shining from tall buildings -- the more light pollution we created flooding the sky above us, making it hard to see the stars.

There are fewer and fewer places where light pollution doesn’t inhibit our view of the great beyond. Almost 99% of the U.S. can’t view the Milky Way.

Demeter argues it’s not just astronomers and scientists who should want to preserve our view of the great beyond.

“When I look up at the night sky. I’m reminded of the thousands of years of history that people have been inspired, a lot of our traditions today stem from ancient people looking up at the night sky and feeling awe and wonder,” he said, adding “I see it as like a national park almost where we want to protect this for generations to come.”

Not long after they made their intentions known to launch thousands of satellites into low-Earth orbit, SpaceX began to hear complaints from the astronomy community. So Musk and Co. began trying to figure out how to make their spacecraft less visible.

Beginning with the 10th batch of Starlink satellites, the company equipped all the spacecraft with a visor that deploys to block sunlight from hitting the brightest parts of the satellite.

“This demo satellite also known as VisorSat is just one of the many actions SpaceX has taken in collaboration with astronomical groups to mitigate the effects of satellite reflectivity,” SpaceX lead manufacturing engineer Jessica Anderson said during a launch livestream in June, adding that all future Starlink satellites will have deployable visors starting with the next mission.

Astronomers also say we’re just now really coming to understand the complexity of this problem.

In August, the members of an American Astronomical Society committee -- who have been working with SpaceX engineers-- released their findings about how to mitigate trashing the night sky and what the long standing impact of these large constellations will be. The group discussed their findings during a press call, saying they hope the recommendations serve as guidelines for observatories and satellite operators to use going forward.

One of the group members, Dr. Connie Walker with the National Science Foundation’s NOIRLab, explained companies could mitigate some of these issues by keeping the satellites at a lower orbit, less than 600 kilometers in altitude, using darkening techniques on the spacecraft and orienting the satellites so there is less surface area to reflect sunlight back down to Earth.

OneWeb -- a communication satellite manufacturing company -- plans to create a space-based internet network by launching around 49,000 satellites at higher orbits of around 1,200 kilometers. So far, they have launched three batches of satellites.

Amazon’s internet constellation known as Project Kuiper, will fly at lower orbits at 630 kilometers and below. The constellation will also top out at more than 3,200 satellites not tens of thousands like some of its competitors.

Lori Allen, also an astronomer with the NOIRLab, said the astronomy working group observed Starlink satellites to determine if changes to the satellite hardware will work and --- what observatories can do.

“We know there will be more in the future and even with mitigations that we will employ overtime we know that some of them will continue to land in our data,” Allen said.

Physics professor Tony Tyson, with the University of California and Davis & Vera C. Rubin Observatory, said Amazon and OneWeb are also beginning to work with the astronomy mitigation group.

“Clearly, SpaceX is leading the charge in terms of trying to understand these issues, and designing mitigations on their satellites,” Tyson said. “Others are getting interested and in particular, as you mention, Amazon and OneWeb, I’ve been contacted by both of them but we are nowhere near down to Earth engineering discussion on how to do this.”

After filing for Chapter 11 bankruptcy earlier this year, OneWeb recently announced that it plans to start launching satellites again in December.

The company was actively engaged with the astronomy community prior to bankruptcy and plans to re-engage very soon.

Amazon representatives continue to meet with the National Science Foundation and the American Astronomical Society to learn more about the impacts of existing satellite systems and how to help prevent furthering the problems they can create.


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