BALLOON-POWERED INTERNET FOR EVERYONE
Project Loon balloons float in the stratosphere, twice as high as airplanes and the weather. In the stratosphere, there are many layers of wind, and each layer of wind varies in direction and speed. Loon balloons go where they’re needed by rising or descending into a layer of wind blowing in the desired direction of travel.
People can connect to the balloon network using a special Internet antenna attached to their building. The signal bounces from this antenna up to the balloon network, and then down to the global Internet on Earth.
NAVIGATING WITH THE WIND
Project Loon balloons travel approximately 20 km above the Earth’s surface in the stratosphere. Winds in the stratosphere are stratified, and each layer of wind varies in speed and direction. Project Loon uses software algorithms to determine where its balloons need to go, then moves each one into a layer of wind blowing in the right direction. By moving with the wind, the balloons can be arranged to form one large communications network.
Situated on the edge of space, between 10 km and 60 km in altitude, the stratosphere presents unique engineering challenges: air pressure is 1% that at sea level, and this thin atmosphere offers less protection from UV radiation and dramatic temperature swings, which can reach as low as -80°C. By carefully designing the balloon envelope to withstand these conditions, Project Loon is able to take advantage of the stratosphere’s steady winds and remain well above weather events, wildlife and airplanes.
Each balloon can provide connectivity to a ground area about 40 km in diameter at speeds comparable to 3G. For balloon-to-balloon and balloon-to-ground communications, the balloons use antennas equipped with specialized radio frequency technology. Project Loon currently uses ISM bands (specifically 2.4 and 5.8 GHz bands) that are available for anyone to use.
Project Loon began in June 2013 with an experimental pilot in New Zealand, where a small group of Project Loon pioneers tested Loon technology. The results of the pilot test have been used to improve the technology, and continued refinements are now being tested in an ongoing series of research flights in California’s Central Valley.