Google Laser-Beams the Film Real Genius 60 Miles Between Balloons
When Baris Erkmen left the NASA Jet Propulsion Laboratory and joined the Google X team that was secretly building high-altitude balloons that could deliver Internet access to remote corners of the world while floating through the stratosphere, one of the first things he did was watch Real Genius.
Erkmen is an engineer who specializes in optical communications—lasers that send data from one place to another. At the JPL, he worked on “free-space optics” that allowed for communication with the International Space Station. And when Google hired him, he slipped into a group of researchers building a similar system for the wildly ambitious balloon experiment called Project Loon. Given the nature of their work, the group has a thing for Real Genius, the mid-’80s Val Kilmer comedy that’s all about building sky-high lasers. Erkmen had never seen it, so the team made sure he did. “It was sort of my initiation,” he says.
The signal must not only travel across a 100 kilometer gap of open air but hit a one-and-a-half-inch target on a floating ballon.
Inside Google X, Erkmen and his teammates are building laser equipment that can transmit data between those high-altitude balloons. The aim is to build a new kind of computer network 20 miles above the earth—a network that can beam Internet signals from balloon to balloon, so that each can transmit a wireless signal to phones down here on the ground. That’s no easy task. In some ways, it’s more difficult than sending a signal between satellites and space stations because you’re not working within the vacuum of space. But after three years of work, Erkmen says, Google has made it happen.
For the first time, the company has revealed that, last year during a test in Nevada, it established a 155 megabit-per-second optical connection between two balloons more than 100 kilometers (62 miles) apart, a little more than the distance between San Francisco and San Jose. “Basically, we’ve been able to connect two terminals that are in two separate cities, up in the stratosphere—for real,” Erkmen says. “It wasn’t a one-time thing, a 30-second success. It was done over three days. We tested during the day. We tested at night. We had many hours of stable and robust communications.”
Compared to what’s possible with fiber lines down here on Earth, that’s not a very fast connection. But it’s enormously impressive when you consider that this signal must not only cross 62-miles of air space but also hit a 1.5-inch target on a floating balloon.
“Free-space optics through the air? That’s not new,” says Joseph Ford, a professor of engineering at the University of California San Diego who specializes in optic communication. “But 100 kilometers? That’s a pretty significant distance. And the fact that they did it from a free-floating platform? That’s cool. It takes advantage of free-space optics in a way that’s pretty elegant.”
These lasers have their limitations. They can’t, say, fire a beam of light down to Earth and pop a giant vat of popcorn.
Among the Google X researchers, who drove the experiment from a makeshift control center set up in a (terrestrial) dining room, there were cheers and hugs all around when the first connection was made. It was a bit like the reaction in Houston when Apollo 11 landed on the moon. And then they sent the first real piece of data between the two balloons: a digital copy of Real Genius. “We got it through error-free,” Erkmen says. “Self-fulfilling prophesy.”
The experiment was one small step for ’80s nerd comedies, but a significant leap toward a world where everyone has access to the Internet. After this initial test, Google performed a subsequent test to send data between balloons at about a gigabit per second—or roughly the speed of the connections Google is now supplying to some US homes through its Google Fiber service. Considering that these balloons must serve thousands upon thousands of phones—not a single home—the company must go even faster still. But work continues. And just down the highway in Menlo Park, California, Facebook is building similar technologies—including drones, satellites, and its own lasers—that can deliver the Internet to those parts of the world that don’t already have it.
In the process, Google and Facebook are working to boost their own prospects. The more people use the Internet, the more people use Google and Facebook. But, yes, these people benefit too. As this tech is deployed, so many souls in places like Africa and Southern Asia gain access to possibilities currently beyond them. Google recently inked a deal to test its balloons with Internet service providers in Indonesia.
Lock and Download
Erkmen and his team work out of the new X lab on San Antonio Road in Mountain View, California. In a clean room just down the hall from where others are honing technologies for the company’s self-driving cars, they build both the laser systems needed to send data and the detection systems needed to receive it. The lasers transmit an (invisible) shaft of light that’s about the diameter of a chopstick and must be accurate enough to hit a 1.5-inch target that’s 62 miles away. Then, a series of additional mirrors and lenses focus it onto the data receiver, which is a mere 60 microns wide, or slightly smaller than a human hair.
All this means the setup also requires second breed of laser: a beacon the balloons shine at each other as a way of reading each other’s position. The beacon sends a fairly broad signal, kinda like the signal that your remote control sends to your television. But this is merely a way of lining up the two balloons so they can aim the far more focused data signal straight at its target. “They search for each other and they find each other’s laser beam and they lock on to it,” Erkmen says.
Over such a vast distance, this is a delicate process. But Google has shown that, in good conditions at least, it can reliably send data in this way. Erkmen compares this to someone trying to aim a laser pointer at a tiny spot across the room. From just 15 feet, he says, that’s enormously difficult, and it becomes even more so as that distance grows. (Give it a try sometime).
“The kinds of accuracies we’re been able to achieve,” Erkmen says of Google’s work with its balloons, “are equivalent to holding a laser pointer on a grain of rice from across a football field … while you’re walking around and moving.”
Real Real Genius
The hope, Erkmen says, is that the company can build a flying network that can bring the Internet to areas where laying terrestrial cables is too difficult and too costly. In theory, Erkmen says, they could connect an unlimited number of balloons. This is still a massive task. But for Ford, it’s doable. “I don’t see any show-stoppers,” he says.
Weather can degrade optical signals. So can scintillation, the atmospheric phenomenon that makes the stars twinkle. But at 20 miles above the Earth, Google’s balloons will float above the scintillation problem—and a lot of the weather. And when the balloons send wireless signals down to the phones below, weather and scintillation aren’t as much of an issue, in part because Google may use electromagnetic technology such as WiFi and LTE, rather than optics.
Google’s lasers do have their limitations. They can’t, say, fire a beam of light down to Earth and pop a giant vat of popcorn, Real Genius-style. But they’ll give you the next best thing: Real Genius.
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