Project Loon is a network of balloons travelling on the edge of space, designed to connect people to the internet in remote parts of the world.
The balloons travel approximately 12 miles (20km) above the Earth’s surface in the stratosphere.
Winds in the stratosphere are stratified, and each layer of wind varies in speed and direction, so Project Loon uses software algorithms to determine where its balloons need to go.
It 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.
The inflatable part of the balloon is called a balloon envelope made from sheets of polyethylene plastic that are 49ft (15 metres) wide and 40ft (12 metres) tall when inflated.
The balloons harness power from card table-sized solar panels that dangle below them, and they can gather enough charge in four hours to power them for a day.
Each balloon can provide connectivity to a ground area of around 25 miles (40km) in diameter using LTE, also referred to as 4G, technology.
Project Loon is partnering with telecommunications companies and mobile networks to share cellular spectrum.
Ground stations with internet capabilities around 60 miles (100km) apart bounce signals up to the balloons.
The signals can then hop forward, from one balloon to the next, along a backbone of up to five balloons.