Google this week launched 30 balloons into the stratosphere in the first step toward creating what it calls a "network in the sky" that could eventually bring "balloon-powered Internet [to] everyone."

Dubbed "Project Loon," Google's balloon-based wireless networks aim to bring 3G-like speed to what Google says are the "2 out of every 3 people on Earth" who lack a fast, affordable Internet connection. Google's plan has been rumored for weeks. As we wrote earlier this month, balloon-based communications are well established for military communications and have been proposed for public safety use in disaster areas. Google could be the first to make balloon-based networks widely used for commercial Internet access.

Google is starting small and admits its system is just in the experimental stages. Google said the 30 balloons launched this week were sent into the air "from the Tekapo area of New Zealand’s South Island" and that a group of 50 pilot testers have been equipped with "special Internet antennas" to try to connect to the network. Google made the announcement late Friday night in the US, Saturday in New Zealand time.

The solar-powered balloons are 15 meters in diameter when fully inflated and are being sent 20 kilometers into the sky. "Project Loon balloons are made of a very thin plastic, about 3mil thick," Google said in a fact sheet. "We use superpressure envelopes—this means the volume of the balloon remains constant, like a mylar party balloon. This lets it float much longer than a balloon that stretches as it inflates."

While some balloon-based communications keep the balloons tethered to the ground, Google's will fly untethered and be controlled from the ground. "One of the most important balloon science breakthroughs of the project was around how to control the altitude of the balloon, which allows us to control where it will fly and to adjust speed," the company said. "The other critical computer science breakthrough we made was around our Mission Control, which makes balloons manageable in groups so they can provide consistent connectivity to a given area."

In a video, Project Loon Chief Technical Architect Rich DeVaul explained that "the stratosphere is different because we tend to have layers of winds that go in very particular directions. By moving up and down through these layers we can steer. By catching the right winds we can keep the balloons together enough to get good coverage on the ground."



Antennas on people's homes will communicate with the balloons. Each balloon "talks" to its neighbors and to a ground station connected to a local Internet provider. Google said this will allow high bandwidth over long distances, with antennas on the ground able to "connect to the balloon-powered Internet when the balloons are in a 20km radius."

Balloons can be directed throughout the world and reused. Once airborne, each balloon is capable of flying for quite a while, from west to east because of the wind patterns in the stratosphere. "If the balloons are circling around the bottom half of the world, eventually the balloon that's over South Africa will pass over South America," said Astro Teller, Google's so-called "Captain of Moonshots." Launches are coordinated with air traffic control authorities.

Google noted that it's not the first to consider balloons for commercial Internet deployments, but previous attempts were stymied by the challenges of trying to keep the balloons in one place. "So the idea we pursued was based on freeing the balloons and letting them sail freely on the winds. All we had to do was figure out how to control their path through the sky," Google said. "We’ve now found a way to do that, using just wind and solar power: we can move the balloons up or down to catch the winds we want them to travel in. That solution then led us to a new problem: how to manage a fleet of balloons sailing around the world so that each balloon is in the area you want it right when you need it. We’re solving this with some complex algorithms and lots of computing power."

Google didn't say what frequencies it is using, but said it has designed its system to filter out competing signals.

Just when Project Loon could provide reliable Internet access to large populations isn't clear. Google said it chose the name "Loon" in part because "the idea may sound a bit crazy." The experiences of the pilot testers "will be used to refine the technology and shape the next phase of Project Loon," Google said. "This is the first time we’ve launched this many balloons and tried to connect to this many receivers on the ground, and we’re going to learn a lot that will help us improve our technology and balloon design."