Satellite Cell Towers Will Beam 4G to Your Phone

In the United States it’s easy to take cell reception for granted. With few exceptions, you can use your phone to text, call, and get online from pretty much anywhere in the country. Yet about 2 billion people around the world live in areas that lack mobile coverage, mostly far from major cities, which makes building a network of terrestrial cell towers to connect them prohibitively expensive. If you built a cell network in space, it could plug the gaps in global mobile coverage by raining 4G service from satellites to users on the ground.

Satellite phones have been around for decades, but they are expensive and their brick-like form factor was inconvenient for everyday use. Now a handful of companies are working to fix this problem by building satellites that can connect to regular cell phones and provide high-bandwidth mobile data anywhere on earth.

Building an extraterrestrial mobile network is tricky because cell phones aren’t designed to communicate with satellites whizzing by at 17,000 mph, 300 miles above the ground. Instead, their software and hardware is optimized to connect with stationary cell towers that are never more than a couple dozen miles away. If you want to connect with cell phones from space, you need an antenna that is sensitive enough to collect their weak signals and powerful enough to return a signal that can be picked up by a cell receiver.

“The hard part is the uplink from the phone,” says Charles Miller, cofounder and CEO of Lynk, a satellite communications company based in Virginia. “You can’t change the phone to add more power. It needs to work out of pocket.”

Within the next two years, Lynk plans to create a constellation of shoebox-sized satellites that will function as orbiting cell towers. Each satellite will use a modified version of terrestrial cell tower software that corrects for things like the Doppler frequency shift caused by the satellite rapidly passing overhead and the delay from sending a signal to space and back. The satellites operate on a relatively low frequency compared to other communications satellites, which means they can tap into the part of the spectrum used by cell phones on earth. Miller says the company has developed an antenna that is both sensitive and powerful enough to communicate with cell phones on earth, but declined to get into specifics of the technology.

In early 2019, Lynk sent its satellite technology to orbit on a Cygnus cargo capsule that docked at the International Space Station. Although it wasn’t a standalone satellite, the payload consisted of Lynk’s core technology and the company demonstrated it could communicate with mobile devices on earth over a 2G network. Since then, the company has launched two other satellite testbeds to the space station and plans to launch a fourth later this month. If all goes well, the next step would be to start launching actual satellites into orbit.

Miller says the company could have a functional satellite cell network as soon as 2022, but it won’t provide global, around-the-clock coverage at first. When the network only has a few dozen satellites, they might pass over users every 90 minutes or so and only provide a few hours of connectivity per day. As more satellites are added to the system, the coverage will improve until the experience of connecting to an orbital cell tower is no different than connecting to a terrestrial one.

But Miller says even a limited connection is better than nothing. “If you’re in a remote area and you only get coverage when you go into town on the weekends, but now you can send and receive messages when a satellite passes over, that’s a valuable service even if it’s only available every hour,” Miller says.

Lynk was joined in space last year by the Texas-based satellite communications company AST & Science, which launched its first satellite, BlueWalker 1, to low-Earth orbit to test their software. AST is building a new, unproven type of satellite constellation that’s a riff on so-called “fractionated satellites,” which divide the capability of one large satellite among several smaller ones. For example, one satellite might host a scientific payload, while another might be responsible for communicating with ground stations. The two would communicate with one another through wireless links. A fractionated satellite system has never flown in orbit, although Darpa spent six years and more than $200 million dollars developing a fractionated satellite before abandoning the concept in 2013 due to budgetary constraints.

AST’s system will consist of dozens of small, pizza box-sized satellites flying in formation as they receive cell signals. According to AST’s founder and CEO Abel Avellan, the system isn’t truly fractionated because each of the small satellites will have the same capabilities, rather than splitting the functionality of one larger satellite. But the formation will be managed by a large control satellite, which will direct network traffic and satellite movement like a conductor leading an orchestra. Although the later versions of the satellites in AST’s system will communicate with one another over Wi-Fi or a similar wireless protocol, Avellan says the first satellites to go up will be physically connected.

The advantage of AST’s approach is that the satellites can be spread out over hundreds of feet. Since each satellite is itself a receiver and is working in tandem with the others, this has the effect of creating a massive antenna. “In essence we are building a very, very large satellite with a lot of power that can connect directly to a handset,” says Avellan. “Our system is a replica of the terrestrial network in space.”

Nothing quite like AST’s vision for its space cell network has ever flown in space, but the audacious plan has already attracted some high-profile support. On Tuesday, the company announced it had raised $128 million in funding to kickstart the network. The funders included Vodafone, the world’s largest mobile provider outside of China, which hails the technology as key to getting the rest of the world online. “We don’t see anything else out there that is going to allow us to connect the next couple of billion people in the world that we aspire to with this platform,” says Luke Ibbetson, the head of group research and development at Vodafone who is leading the company’s collaboration with AST.

Lynk and AST & Science are leading the race to build a cell network in space, but they may be joined by Apple, which has been reported to be building space phone technology. Last year, Bloomberg reported that Apple “has a secret team working on satellite technology that the iPhone maker could use to beam internet services directly to devices, bypassing wireless networks.” It’s uncertain whether Apple plans to develop its own satellite constellation. Apple did not respond to WIRED’s request for comment.

Despite the burgeoning interest in space-based cell networks, the idea itself isn’t new. In the mid-2000s, a company called TerreStar also sought to create a 4G satellite network that would connect with devices that were a hybrid of satellite phones and regular cell phones. The device, known as the Centrus, looked a bit like a Blackberry and was designed to be able to switch between terrestrial and satellite cell networks. Alas, no one ever really had a chance to use the thing. TerreStar filed for bankruptcy in 2010, just a few months after it launched its first satellite.

Avellan says this time things are different. He cited the rapidly falling cost of space access thanks to reusable rockets, as well as the miniaturization of key technologies such as software-defined radios as the main reasons that space-based cell networks are finally viable.

Both AST and Lynk executives see it as their mission to bring cell coverage to people who lack access to emergency communications, weather reports, banking, and other benefits offered by mobile devices. Many of these people are concentrated in India, Indonesia, and equatorial Africa, but Miller says space-based cell service will be valuable to people who live anywhere out of the reach of cell towers, which he calculates to be about 75 percent of the planet.

“If you go an hour outside of Washington, DC, into western Loudoun County, there are plenty of areas even on major arterial roads that have no connectivity,” Miller says. “It’s just the economics of cell towers—you can’t afford to build them everywhere.”

The big question is whether anyone will pay up for space-based satellite service even if the technological hurdles are overcome. Both Lynk and AST have struck partnerships with telecommunications companies that are helping them integrate with their networks to test the space-based cell service. When the satellite networks are ready, Lynk and AST will sell the service to telecommunications companies that will roll the satellite service into existing plans and presumably extend these services to places where people don’t have cell connections. But will they be able to find enough customers who want to pay when service is still spotty and might only be available for a couple hours per day? Without a substantial user base, it may be difficult for space-based cell networks to raise the massive capital needed to launch enough satellites to provide global, around-the-clock service.

“The plans are ambitious, but they’re credible,” says Ibbetson. “We’re a few years off from actually launching service, but the signs are all extremely positive.”

Both Lynk and AST have a lot to prove. The history of commercial space exploration is rife with companies that built great technology yet couldn’t find enough customers before their coffers ran dry. Although both companies have conducted some successful tests of their core technologies in orbit, the market will be the ultimate arbiter of their future—or whether they have a future at all.

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