Last month, Ofcom, the United Kingdom’s telecom regulator, granted Amazon’s Kuiper Systems a license to provide low-Earth orbit-based (LEO) broadband Internet in the country. The move places Kuiper systems in a rival position with the industry leader, and SpaceX subsidiary, Starlink Services. And while more specialized LEO broadband Internet interests are also emerging—in the public and private sectors—Ofcom’s decision signifies an important shift in consumer LEO internet providers. The game is shifting, in other words, from a single-player to a multiplayer one.
Which is not to say, however, that the game today is evenly matched. As one analyst from Copenhagen-based Strand Consult recently put it in the industry publication Broadband Breakfast, Kuiper now is just “a burger bar, while [Starlink Services] runs an interstellar McDonald’s.”
In fact, “burger bar” is being charitable.
According to satellite industry data clearinghouse planet4589.org, as of this story’s publication, the SpaceX subsidiary Starlink had 7,050 active satellites in low-Earth orbit (LEO). Whereas Kuiper Systems has only two prototype satellites now in the sky. The company’s first non-prototype launch is currently being slated for an as-yet unspecified date this year. In addition, as Kuiper parent company Amazon announced on social media in late January, “another batch” of satellites was at the time headed to Cape Canaveral to be prepared to be lofted into space as well. Assuming both Kuiper launches can happen soon and without a hitch, that would still leave a huge gap between the number of deployed Kuiper satellites and the 1,663 that Kuiper Systems’ FCC license mandates being in orbit and operational by July 2026.
Kuiper’s Satellite Catch-up
To be fair, Kuiper Systems hasn’t exactly been sitting idle. Scott Palo, professor of aerospace engineering at the University of Colorado, Boulder, says that establishing an inter-satellite optical communications network is one of the biggest challenges in satellite-based wireless and broadband networks. The technology is based on free-space optical links—laser light beamed between the fast-moving satellites that transfers data at high rates, enabling the data to be transmitted to an appropriate ground station. And Kuiper already demonstrated the orbiting system’s capacity to optically interconnect at the end of 2023.
Meaning that Kuiper has at least demonstrated the capability to do what Starlink Services has been doing day in and day out since 2021, when the SpaceX subsidiary first launched laser-interconnect satellites as part of its emerging LEO internet constellation.
“The pointing challenge is multi-faceted,” Palo says. “The first challenge is just trying to find the other terminal. Consider standing at opposite ends of a football field with a friend. You and your friend each have a laser pointer and are looking at each other through a straw.”
But of course, he adds, for a satellite internet constellation like Starlink or Kuiper, the friends looking through straws on either ends of a football pitch are each moving rapidly and following trajectories that can be challenging to track and forecast.
To get as precise a fix as possible on each satellite’s orbit, says Kerri Cahoy, MIT professor of aeronautics and astronautics, requires a whole different constellation orbiting higher still. GPS satellites are in medium-earth orbit (MEO) at some 20,200 kilometers above the earth. By comparison, satellite-based broadband systems operate well below GPS orbits, at altitudes of between 340 km and 630 km—for Starlink and Kuiper satellites—and at 1,200 km orbit, for the competing LEO broadband constellation OneWeb.
In October 2023, Amazon subsidiary Kuiper Systems launched a prototype pair of satellites to test the company’s satellite broadband technologies. Amazon
“You need to have well-determined orbits on each of the satellites—they each need to know where to point,” Cahoy says. “In low-Earth orbit they use both GPS receivers as well as high precision attitude determination and control systems—star trackers with reaction wheels.”
Cahoy and Palo take a different view, however, about just how essential optical interconnects are for a functional LEO broadband constellation.
Optical interconnects, Palo says, “are critical for a connected space ecosystem.” Satellite-to-satellite interconnects that use radio communications instead, he adds, “cannot compete with the performance of optical systems and space-to-space communications over long ranges.”
On the other hand, Cahoy notes that while a good optical interconnect system can be quite effective, “it’s possible to have a successful service without optical,” she says. Connecting a satellite broadband network together via radio frequency communications—as SpaceX first did in 2019 and 2020 when it was first testing the Starlink system—is still doable, in her opinion.
Plus, while laser interconnects are fundamental to Starlink operations today, she says, “We’ll learn more about how well the optical systems hold up in terms of lifetime and aging in the space environment.”
Starlink’s LEO Dominance
Starlink satellites constitute more than half of the active satellites now in orbit around the Earth, says Jonathan McDowell, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. “Particularly in low Earth orbit, they’re dominating,” says McDowell, who’s also founder and data keeper at planet4589.org. “And in terms of large satellites in the lower orbits, they’re really hugely dominating.”
And yet, even with Starlink’s oversized orbital footprint today, LEO Internet constellations still face bottlenecks in the total number of subscribers they can serve. In 2021, the New York-based consulting firm Moffett Nathanson published a technical white paper estimating that, even with aggressive launch schedules and high consumer demand for bandwidth, Starlink might only be able to provide Internet connectivity to no more than one percent of households in the United States. Commenting on his firm’s forecast with present-day numbers, analyst Craig Moffett of Moffett Nathanson says that while a few factors in the firm’s original calculations had changed in the intervening four years (e.g. more satellites in orbit, but with lower-speed connections than anticipated), “Starlink’s addressable market remains tightly capacity constrained.”
An actuator constitutes a step on the solar array assembly line for a Kuiper Systems satellite—one element of a next wave in satellite-based broadband internet.Amazon
Danielle Wood, director of the Space Enabled Research Group at MIT’s Media Lab, says Starlink and Kuiper don’t optimally serve densely populated regions of the globe. “I’m in Boston,” she says. “I don’t need satellite-based Internet. I’ve got fiber and various other options that are fine. People who need this are in rural areas that have low population densities.”
Which still leaves plenty of the planet yet to be connected to reliable broadband—or even reliable cell service. And in that world, Kuiper and Starlink are the big contenders today. But they’re not the only players on the field, or potential players looking to get in the game.
London-based EutelSat OneWeb, for example, is operating a constellation of more than 650 active satellites for government and maritime broadband and wireless. And according to McDowell, China is expected to begin rolling out their own LEO Internet and wireless constellation—ultimately of some 20,000 or more satellites. (Which is already more than the 14,000 anticipated satellites that Spectrum reported China would be launching last August.) “And then following the use of Starlink in Ukraine,” McDowell adds, “A lot of militaries around the world are starting to go, ‘Huh, we want these. And we’re not going to use Elon’s. We want our ones under our own control.’”
Collision Avoidance in LEO Satellite Orbits
Add up all these LEO broadband ambitions—commercial, military, and national—over the next decade, McDowell says, and the number of active satellites in the sky would jump from today’s approximate 10,000 count to something closer to 100,000.
And that could be a problem.
Nearly 50 years ago, NASA scientists envisioned a future in which the amount of stuff zipping around in LEO reaches a threshold, beyond which navigating some earth orbits could ultimately produce cascading storms of collisions with satellites, space junk, and debris from previous collisions. The phenomenon, called the Kessler syndrome after one of the scientists, Donald Kessler, represents a cautionary tale that’s been explored—with some dramatic embellishments—in the 2013 movie Gravity and in Neal Stephenson’s 2015 novel Seveneves.
McDowell says he expects that the Kessler syndrome could emerge as a real concern in LEO somewhere between the 10,000 and 100,000 satellite count. “We’re probably going to find out the hard way,” he says.
What’s not guesswork is the amount of collision avoidance that present-day LEO satellites need to perform all the time. According to filings with the FCC, Starlink satellites performed more than 50,000 collision-avoidance maneuvers between June and November of last year.
“Before Starlink, the most people maneuvered their active satellites was a few times, typically,” McDowell says. “Maybe a hundred times in a very maneuverable mission. And so having that number of maneuvers is just enormously more than we’ve seen in the past.”
MIT’s Wood has helped to develop numerical models for LEO satellite collision-avoidance maneuvers, and she agrees that the rate of collision threats in LEO today is growing at an astonishing rate. In fact, her group is championing a space sustainability rating system that encourages open dialogue between LEO satellite operators and the space industry. To date, she says, OneWeb is the only LEO satellite provider to earn the rating system’s highest space sustainability score.
To keep the LEO Internet broadband industry thriving, and the Kessler syndrome ultimately at bay, she says, more cooperation and communication between companies and governments is needed. “We can’t maintain the same pace of just adding new satellites in a way that’s going to guarantee safety,” she says. “We all want to have great communication satellites and NASA science satellites and other satellites for weather, for example, that are all going to work together safely in space. And we’re not on a path toward doing that well.”
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