It is estimated that over 60% of the population does not have access to the internet. Google is aiming to change this with the help of high altitude balloons and innovation. They plan to launch balloons into the earth’s stratosphere in order to achieve this. Aptly named Project Loon, is a network of balloons travelling on the edge of space, designed to extend internet connectivity to people in rural and remote areas worldwide.
The stratosphere is the second major layer of Earth’s atmosphere. It is situated at nearly twice the height that commercial airplanes fly at. Within the stratosphere there are different layers of winds, travelling in different directions, at different altitudes. In order to steer the balloons they must be brought up or down to use the different wind layers. A complex choreography is used to steer and program the balloons in an automated fashion. A balloon needs to come at just the right time to replace a balloon that has just left. Over the past few years Google have learnt a lot about wind and have become better at predicting where the wind will take their balloons. With their latest navigation update they can now send small teams of balloons to specific areas. Allowing Google to bring useful connectivity to those areas without the need for a continuous stream of balloons. This development will make it much easier to bring balloon powered internet to those who need it, much sooner than anticipated.
Project Loon works by using telecommunications partners on the ground and the LTE protocol. Once in the sky, high speed internet is transmitted to the balloon then relayed across the balloon network before being relayed back down to users on the ground. Testing has demonstrated data transmission between balloons over 100 km apart with connection speeds of up to 10 Mbps to people on the ground to people directly to their LTE phones.
Each balloon is made from a special formulation of polyethylene plastic, designed to withstand extreme temperatures, with a thickness of 0.076mm. The balloons are filled with helium and have a span of 15m and stand 12m tall when fully inflated. In order to control the elevation in order to steer, the balloon is equipped with a custom air pump system. The system acts as a ballast by pumping and releasing air of the ballonet. A ballonet is an air bag inside the outer envelope of the balloon which, when inflated, reduces the volume available for the lifting gas, making it more dense. The other electronic equipment is contained in a small box weighing 10kg that hangs underneath the inflated envelope.
Google has constructed auto launchers which are capable of safely and consistently launching a new balloon every 30 minutes. The record for the longest surviving balloon in the stratosphere is an astonishing 190 days aloft. Up to date through the duration of the project, test flights collectively have covered a distance of over 19 million kilometres.
Mission control is able to track and optimally position each balloon in order to provide internet to the ground. The location and projected trajectory of each balloon is carefully tracked from launch all the way until the balloon comes down and is recovered. With recent developments the company can now land balloons within 500 metres of a target after flying for 10,000 kilometres and download speeds of 50Mb/s are being supported by the 4G balloon.
When the project first began in 2011 the initial tests showed that there was huge potential. At first the balloons were taped together by hand and took 3-4 days to assemble. These balloons were found to have micro leaks and would only last a few hours or if they were lucky a few days. They were only able to launch one balloon a day. Now with their own automated systems balloons can be produced in a matter of hours and are durable enough to last over 100 days. The automated launchers have made it possible to launch dozens of balloons each day for each crane that they have.
Although Project Loon has not yet announced a competition date it certainly seems to be ahead of its competition and well on it’s way. For more on Project Loon.
