CASPER, Wyo. — University of Wyoming Professor of Physics & Astronomy Daniel Dale was backpacking in the Snowy Range last month when he suddenly spotted something moving in the moonless night sky.
“It was pretty insane,” he said, recalling the site of some 60 bright, low-orbiting satellites in a perfect line speeding overhead.
“It was the first time I’d seen it, and there was the ‘wow’ factor,” he said, “but scientifically in the back of my head I was thinking, ‘this is hideous.’”
Social media chatter reflected that initial excitement as many around Wyoming saw the strange and stunning train of lights, looking like something straight out of Hollywood sci-fi movies.
“My colleague who isn’t an astronomer said, ‘If you weren’t here I’d probably call the sheriff about an alien invasion,’” Dale said.
Elon Musk’s SpaceX company is in the process of filling Earth’s orbit with their Starlink satellites, which the company will use to provide high-speed internet services to almost every underserved rural area on the planet. At least 2,500 have been placed into orbit already, and dozens more are launched each week.
According to Astronomy.com, the so-called “satellite trains” consist of a cluster of small satellites released from SpaceX’s cargo rockets, which fly in a “parking orbit” for several days. From there, the individual satellites open their solar panels and deploy into their permanent orbits around the planet by using small rockets.
The trains are most noticeable because they’re flying in their lowest orbit, but even when the satellites move upward they can still be easily seen from Earth. In contrast, traditional satellites are very large and orbit far out in space, making them more “visible” to dishes by overcoming the planet’s circumference, but in turn more difficult to see by eye and ground telescopes. Musk’s satellite “constellations” are orbiting much closer to the planet, and in exponentially greater numbers. As of 2021, SpaceX owned nearly half of the satellites in space. And that’s barely the beginning.
SpaceX alone intends to eventually have at least 42,000 satellites launched for Starlink, and astronomers fear that other governments and companies around the world are signaling they would like a piece of that space pie. According to Astronomy.com, such companies as Amazon and OneWeb are working on their own systems, and China is said to have one in the works that resembles Starlink.
“This has really blown up over the past half-dozen years because of the commercialization of space,” said Alan Corey, president of the Central Wyoming Astronomical Society.
“Since I was a little kid I’ve been looking at the night sky and I’ve always been awestruck,” Corey said. “Now I look up and I see artificial satellites orbiting nonstop.”
The aesthetic and emotional value of losing the night sky runs deep for many, but professional astronomers are facing potentially catastrophic consequences.
The Vera Rubin Observatory currently under construction in Chile will use the most advanced technology available to produce “the deepest, widest image of the Universe,” according to its website. The telescope will use the world’s largest CCD camera to take multiple images of the sky each night over several years to, among other goals, take an inventory of the solar system, map the Milky Way, and research energy and dark matter.
Satellite constellations weren’t of any concern when construction started. Now, a considerable amount of data the observatory will collect might be severely compromised.
“[Skylink] is just gonna frankly obliterate a lot of that good science,” Dale said. “Looking at statistics that the American Astronomical Society are putting out, something like 30% of images are going to have some kind of streaking from the satellites, and up to 90% of them will be at twilight. Almost every image taken by this fancy new observatory that we’re just about to open up is going to be compromised.”
The problem goes even beyond optical astronomy.
“These satellites have their own radio frequency emissions,” Dale said, “so they can also mess up radio astronomy, infrared astronomy, [and] X-ray astronomy.”
Several factors make satellites hundreds of miles away visible on Earth. The bright light is actually caused by reflections from the sun, making them most visible at twilight time around dusk and dawn, Dale said. Naturally they can’t be seen in bright daylight, and the Earth blocks the sun’s reflections later at night.
Why don’t satellite designers just paint them black?
“They’ve tried different concoctions of paint colors on these things, and the sun heats them up too much and it ruins the components, so they have more reflective paint,” Corey said. “I think some of the components are painted white, which is obviously way more reflective than any other color.”
Corey says Starlink’s satellites have solar panels that are aimed towards Earth when they’re in their early, lowest-orbiting train position.
“When they get into their operational state, their solar panels turn vertical and perpendicular to the Earth, so we shouldn’t see their solar panels once they’re in operational mode,” he said. “What we do see in their operational mode is that reflective paint.”
According to SpaceX’s website, Starlink satellites have an expected five-year lifespan. After that, SpaceX says the satellite is put into a controlled decent and should disintegrate in Earth’s atmosphere. They also say they are working closely with astronomical associations to make the satellites less visible.
However, the sheer number of satellites proposed in the near future could far outweigh any design tweaks.
A study recently published by the Scientific Organizing Committee gives a dire warning.
“If the 100,000 or more LEOsats proposed by many companies and many governments are deployed, no combination of mitigations can fully avoid the impacts of the satellite trails on the science programs of current and planned ground-based optical-NIR astronomy facilities,” they said.
The mass of man-made reflections could likely cause increased light pollution in the night sky, affecting Native American religious observations and animal migrations that rely on natural constellations.
“Light pollution has always been an issue, but this has a different flavor,” Dale said.
“I think it’s eight out of 10 people on this planet who have never seen the Milky Way because of light pollution,” Corey said. “You know, as the overall brightness increases, that number is only going to grow.”
“Starlink is just the beginning; we’re gonna see a lot more of it,” he said.