Reining In The Cosmos: The Case For Controlled Satellite Deployment
By John Oncea, Editor
Dinosaurs never knew what was coming when an asteroid wiped them out 65 million years ago. Today, due to light pollution caused in part by the proliferation of satellites, humans may be blinded to an asteroid coming to wipe us out.
About 150 miles east of my hometown of Erie, PA – 41.6501 degrees north, 77.8164 degrees west, to be exact – in the largely undeveloped 106,000-hectare Susquehannock State Forest sits Cherry Springs State Park. At the top of a 2,300-foot high mountain, Cherry Springs is the world's second certified Dark-Sky Park and is well known for its dark skies and views of the Milky Way, planets, and other astronomical objects.
According to the park’s sites, “On a clear night, up to 30,000 stars fill the sky, and lucky guests may also glimpse Asteroids, Venus – the evening star, Aurora Borealis (the Northern Lights), Omega Nebula, Zodiacal Light, Meteor Showers, Lunar Viewing and the Milky Way, and other celestial bodies.”
The sky at Cherry Springs is classified as a 2 on the Bortle Dark-Sky Scale, meaning it has almost no light pollution. The park shields all lighting and has converted all white light to red to minimize the amount of ambient light and increase the spectacular nighttime sky views.
But Cherry Springs can’t eliminate or even reduce one source of light – the skyglow generated by the more than 8,500 satellites currently orbing the Earth.
Come For The Fat Bears, Stay For The Light Pollution
Back in October, the podcast Short Wave broadcasted “It’s Fat Bear Week!” While fat bears are indeed an intriguing topic, we’re here to talk about another story that ran as part of that day’s podcast – the problems caused by light pollution from satellites.
Astronomers are worried that the growing number of satellites is making it harder to see the night sky, constellations, and even the Milky Way, as well as interfering with sensitive astronomical instruments. In addition, as the number of satellites in orbit increases, so does the risk of collisions and the creation of space debris. This debris can create a chain reaction, adding to the cloud of “space junk” that reflects light on Earth.
The proliferation of satellites is being driven in part by communication companies trying to make good on promises of reliable internet to the most remote places on Earth. To accomplish this, they are launching networks of satellites such as Starlink from SpaceX which currently has about 3,000 satellites in space with plans to launch thousands more. As Short Wave points out, that’s just one company and the brightness its satellite network is producing can ruin data for ground-based telescopes.
Short Wave spoke with observational astronomer Jeremy Tregloan-Reed, co-author of a paper in Nature focusing on measuring the brightness of the biggest commercial satellite in space, BlueWalker 3. He says only seven stars in the sky are brighter than BlueWalker 3 which is 64 times bigger than the first-generation Starlink satellites. AST SpaceMobile, the company behind BlueWalker, plans to launch more satellites, including five Block 1 BlueBird satellites in the first quarter of 2024.
Is Humanity At Stake?
“The light reflected by these satellites is making the night sky brighter, especially at dusk and dawn, which happens to be the time astronomers hunt for dim, potentially dangerous asteroids,” Short Wave reports. “So, these bright satellites are interfering with our ability to find rogue space rocks.”
As of now, governments have made no effort to regulate this and prevent us from being crashed into by an asteroid, but “there is a group made up of experts called the International Astronomical Union (IAU) that does have recommendations for how bright these satellites can be without strongly affecting science. The union, of course, can't legally require companies to do anything. But they do lobby, and they do a pretty good job working with industry so that they know how to modify future satellites.”
Beyond an undetected, rogue asteroid crashing into Earth, blocking out sunlight, causing climate change and global wildfires, and eventually creating a nuclear winter that drives a mass extinction event, there is another way light pollution from satellites is affecting humanity.
Karlie Noon, an astronomer at the Australian National University and a Gamilaraay woman, says Starlink and other satellites are also threatening Aboriginal cultural knowledge and messing with migratory animals’ instincts, according to The Guardian.
First Nations knowledge, according to Noon, is stored in stories, song, dance, the land – and the sky which holds cultural knowledge and tells the stories of the changing landscape. “It moves and evolves as the sky moves and evolves,” Noon says. “Things like understanding the seasons from an Indigenous perspective – what the animals are doing, what the plants are doing, what the weather’s doing, this is all read from the sky.
“From a Gamilaraay perspective, the Milky Way is so many things, its sky camp, it talks about Emu, Crocodile, an important creative being for us. It has all these layers. And we can barely access it. If we can’t see the constellations, we can’t access our knowledge.”
The Future Could Be 12% Brighter, And That’s Not A Positive
Satellites do not emit their own light. Rather, they reflect sunlight as they orbit our planet. Their brightness and visibility to the naked eye depend on various factors such as their size, design, orbital height, and the angle at which the Sun shines on them. Some satellites can appear as bright as the brightest stars, while even the dimmer ones can leave streaks on astronomical images. During summer, satellites can be bothersome to observers at high latitudes throughout the night. However, during winter and closer to the equator, they are more visible toward dusk and dawn.
“Since 2019, the number of functional satellites in low-Earth orbit has more than doubled,” Sky & Telescope points out. “But the real problem lies in the near future: Plans to launch up to 100,000 more within just a few years are well underway.”
Senior researcher at the Astronomical Institute, Slovak Academy of Sciences Miroslav Kocifaj and colleagues estimate that the night sky at its zenith is up to 10% brighter than it was at the beginning of the Space Age. “Given this projection (it is expected) that by 2030 the night sky at zenith will be at least 12% brighter as compared to a natural dark sky, counting the effects of both intact satellites and debris.”
Most of that will be caused by space debris with recent work indicating that intact satellites will only add about 1% to the diffuse brightness of the zenith. “Space debris is anything human made in orbit that isn’t a working piece of technology: retired or broken satellites, leftover rocket stages, satellite parts, and tiny pieces from collisions,” writes Sky & Telescope.
Also contributing to the volume of space debris are fragments created when satellites collide with each other. The more satellites in space, the more chance there is for collisions. And the more collisions that occur, the more space debris. Repeat, repeat, and repeat.
Fewer Satellites?
“So far, some companies have attempted to reduce the reflectivity of their satellites, and astronomers have worked on algorithms to remove satellite streaks from their data,” Sky & Telescope writes. “But these strategies … have had only limited effect.”
SpaceX attempted to reduce the brightness of their Starlink satellites with designs called “DarkSat” and “VisorSat” but both designs failed to make the satellites less visible to the naked eye and were eventually abandoned due to engineering issues. While correction methods are available to help improve astronomical images, they cannot recover all of the data lost due to the brightness of Starlink satellites. It is important to note that none of these strategies address the issue of space debris.
While reducing the number of satellites in space is something the commercial space industry would fight tooth and nail, it is an option that governments can choose to impose. Barring any unforeseen developments, simply launching fewer satellites and placing restrictions on the number of objects allowed at certain altitudes may be the only way forward for sustainable space.