A fleet of UFOs, a bizarre alignment of meteors, a drone show: These are just a few of the things SpaceX’s Starlink satellites have been mistaken for of late.
National Geographic photographer Babak Tafreshi, however, knew exactly what he was seeing on a recent July evening in California’s Pinnacles National Park, when a “caravan of satellites” paraded across the sky, aligned as if they were perfectly-spaced stars.
“I see them very often because there are just so many of them,” he says. “People react because they have no idea what it is.”
These satellites bring broadband internet to some of the planet’s most remote reaches. They are usually seen in low-earth orbit (around 186 miles from ground) on their way up to their final orbit at 342 miles high. As they rise, they grow dimmer and spread out until they’re mostly out of sight of the naked eye, which can take up to several weeks. Astronomers call these massive arrays of satellites “mega constellations.”
In recent months, these satellites are being launched more frequently, often with over 50 satellites at a time, by Elon Musk’s commercial space company. Sightings of Starlink mega constellations are also becoming more common, says David J. Helfand, a professor of Astronomy at Columbia University.
The satellites are making it much more difficult for astronomers to do their jobs, he says. “When a satellite goes through the field of view of a telescope, it’s extremely bright,” Helfand says. “The objects we’re trying to study–distant galaxies and stars–are 20 million times fainter than satellites. So when one of these streaks goes across the image, it completely obliterates the image.”
At least 6 percent of the 2021 images from the Hubble Space Telescope were “compromised or completely ruined” by satellite interference by Starlink satellites, he says. “That’s when there were only 1,500 Starlink satellites…Now there are three times that amount.” And many more are on the way.
Satellites: an invaluable tool, an astronomic obstacle
In a February press release, SpaceX said they’d launched “nearly 4,000 satellites” over the last five years. They aim to send up to 42,000 satellites into its mega constellation in coming years, according to Space.com. SpaceX did not respond to National Geographic’s request for comment.
These satellites can be seen with the naked eye in the days following their launch (when their orbit is lower to Earth and satellites are still close enough together to appear in a line), and in the hours just after sunset and just before sunrise. Websites like Heavens-Above.com predict when Starlink satellite trains will pass overhead for people looking to spot them.
Satellites like Starlink’s have long been used to enhance mobile services like cell phone coverage, internet and GPS navigation for people on Earth. Satellites also make weather forecasting, TV signaling, radio, and military surveillance possible.
But before Starlink launches, there were no “trains of satellites” to be seen, says Tafreshi. SpaceX uses new satellites that can be folded up in the dozens and sent into space on private rocket launches out of Cape Canaveral in Florida and Vandenberg Space Force Base in California.
“You used to see a couple of satellites at the beginning of the night and it was very cool to see a ‘moving star’ in the sky,” Tafreshi says. “Now, every direction you look there are a few moving above you. They’ve stolen the show from the stars.”
While Starlink satellites in low-earth orbit aren’t the brightest man-made objects in the sky, it’s the sheer number of them that’s worrying, says James Lowenthal, professor of astronomy at Smith College. “Starlink’s appear very bright when they're first launched into low orbit—brighter than the great majority of naked-eye stars,” he says. They become fainter as they are both moved to higher orbit as well as actively controlled to face certain directions–primarily for their own communication, but in part to make them appear dimmer, too.
Other companies with mega constellation projects in the works include Amazon’s Project Kuiper, currently planning a mega constellation of 3,236 satellites for broadband internet purposes. AST SpaceMobile’s BlueWalker 3 will start with 100 satellites and they may be brighter than 99.8 percent of visible stars, according to New Scientist.
Regulating our skyscape
When Lowenthal witnessed Starlink’s first satellite launch in 2019, he says he knew “the sky would never be the same again.”
A lack of international regulation and environmental oversight is endangering the sanctity of our skies like never before, says Aparna Venkatesan, a professor in the department of physics and astronomy at the University of San Francisco.
"We have no framework in place to conduct environmental assessments of all phases of satellite constellations, from launches to in-orbit operation to decommissioning,” she says.
Thousands of satellites break down in the atmosphere, leaving an estimated million pieces of space debris “criss-crossing at high relative speeds” and increasing the chance of collision with other space crafts, a 2021 paper asserts. These rockets also leave behind sooty discharge called black carbon, which could cause “changes in the global atmospheric circulation and distributions of ozone and temperature,” according to a 2010 paper.
Satellites contribute to light pollution by reflecting the sun’s light and also by their sheer numbers. Dark Skies organizations are fighting to minimize artificial light at night both to protect local ecosystems, and also to respect communities whose identities are closely tied to the night sky.
“Rapidly growing ground- and space-based light pollution is erasing Indigenous stories and identities—again—as history is painfully repeated for marginalized communities already disproportionately impacted by climate change and other crises,” Venkatesan says.
SpaceX has “done some due diligence,” says Vishnu Reddy, director of the Space4 Center at the University of Arizona, which measures the brightness of Starlink mega constellations and their impacts on ground-based astronomy.
Newer Starlink satellites “don’t reflect as much,” as the first generation satellites from 2019 and 2020, Reddy says, and some older ones have also been “deorbited‚”—falling out of orbit and burning up in the atmosphere.
Lowenthal agrees that SpaceX “quickly heard the alarm from astronomers around the world,” engaging in conversations with astronomers from the company’s first Starlink launch. “What they haven’t done, however, is slow down launches,” he says. “We have always relied on our ability to turn to the night sky for solace and personal connection as well as scientific study…that’s all threatened.”