How Google Loon Works

Project Loon's balloons are not your typical party balloons, which wouldn't fare well in the extreme conditions at high altitudes. Party balloons also wouldn't be able to carry much equipment. The Google Loon team has developed something more akin to a weather balloon, designed to withstand tough atmospheric conditions such as pressure differences, high winds, UV exposure and extreme temperatures, which are often well below freezing at higher altitudes. That means they can stay aloft much longer than any previously developed balloons. The various balloon models have been nicknamed after birds, including the Falcon, Ibis, Grackle and most recently NightHawk.

The balloons are made of polyethylene plastic around the thickness of a sandwich bag. Each inflated balloon (the portion referred to as the "envelope" of the balloon) is approximately 50 feet wide by 40 feet high (15 meters wide by 12 meters high), with about 5,381 feet (500 square meters) of surface area. Their size necessitates working on them in giant hangars, such as Google's rented space at Moffett Federal Airfield in California.

The balloons have two chambers (sort of a balloon within a balloon), the inner one filled with air and the outer one with helium. Valves and a fan attached to the bottom of the balloon can be used to pump air in or out. Adding air to the inner balloon increases the mass and causes the balloon to go down, and releasing air causes it to go up.

Many of the project's earlier balloons burst or didn't stay in the air very long. The team has gone to great lengths to analyze problems and make improvements. Google enlisted experts in ballooning, aerospace, textiles and other disciplines to learn why they were failing, and hired ex-military personnel to retrieve downed balloons (which sometimes fell in hard-to-reach places).

Some of the testing has been carried out in extreme conditions such as those the balloons might face in the atmosphere. At one point, temperatures fortuitously dropped to sub-freezing temperatures in South Dakota, one of the balloon manufacturing locations. More recent testing was done at the McKinley Climatic Laboratory at Eglin Air Force Base in Florida, which allowed them to subject the balloons to extreme weather conditions, such as high winds and below freezing temperatures, in controlled lab environment.

Many of the failures were found to be caused by tiny, leaks that were hard to detect. Even the tiniest pin-sized hole would greatly decrease a balloon's time in the air. Due to the findings, the seams were strengthened, and more careful balloon handling protocols were implemented, including team members only walking on them in very soft fuzzy socks.

Aside from improving the viability of its own project, Google's efforts have provided breakthroughs in ballooning itself. Due to design improvements, their balloons now stay afloat around 100 days. One even stayed up a record 187 days and circled the planet nine times [source: Raven Aerostar]. These are flight times that were unheard of before, and considered by some experts to be impossible.

The Loon team has also improved the deployment process a great deal since the beginning of the project. A crew used to have to lay the balloons out on tarps and unwrap and partially inflate them before launch, and they could only be launched in winds of 6 miles (9.7 kilometers) per hour or lower. But Google has developed Autolauncher (called the Bird House internally), a 50-foot (15.2-meter) tall portable hangar with an automated crane to stretch and fill the balloons. They can now be launched in 15 mile (24 kilometer) per hour winds, and the work that used to take 14 people and 45 minutes now takes 4 people and 15 minutes. These improvements make keeping enough balloons afloat to form a network more feasible [sources: Metz, Stone].

Google is, of course, not sending up balloons alone. Each balloon has a metallic box of electronic equipment hanging from the bottom via cord with attached solar panels for power.

Each solar panel is an array of monocrystalline solar cells encased in plastic laminate and held in an aluminum frame measuring about 5 feet by 5 feet (1.5 meters by 1.5 meters) in width. Two such panels are mounted facing outward from each other at sharp angles to catch what sunlight they can as the balloons spin. They generate around 100 watts of power in a few hours of full daylight, which is stored in batteries so that the equipment will continue to work in darkness.

The electronic payload includes computing equipment to control everything, rechargeable lithium ion batteries to store the sun-gathered power, GPS units to track balloon locations, dozens of sensors so that Google can monitor for atmospheric conditions and radio equipment for wireless communication with other balloons and with ground-based networks. The radio equipment includes a broad-coverage eNodeB LTE base station, a high-speed directional link and a backup radio.

According to Google, the connectivity provided by each balloon should cover an area of approximately 25 miles (40 kilometers) in diameter on the ground, with hundreds of people potentially able to connect to a balloon at the same time. The Loon team has also increased the data rate by 10 times since the beginning of the project [source: Google]. They expect coverage to be on par with typical LTE 4G network speeds. Project Loon's leader, Mike Cassidy, has stated that their balloon networks could cover as much as 5,000 square kilometers (1,931 square miles) on the ground, and provide service at 15 megabits per second on a phone, or 40 megabits per second on a MiFi device [source: Verge].

The first layer of Earth's atmosphere is the troposphere, where we live and where most weather occurs. The balloons will float in the next layer up, called the stratosphere. The lower end of the stratosphere starts between 4 and 12 miles (6 and 20 kilometers) above the surface of the planet (lowest at the poles and highest at the equator), and the upper stratosphere ends at around 31 miles (50 kilometers) above the Earth. The Loon balloons will float between 11 and 17 miles (18 and 27 kilometers) up, around twice as high as commercial aviation routes.

In the stratosphere, there's little water vapor, very few clouds and no weather to speak of. It's also colder toward the bottom and hotter toward the top, which prevents the gases from rising, creating a situation where there are relatively stable layers at different altitudes. At these layers, the wind blows in different directions and speeds in predictable ways.

Google has been analyzing historical wind-related data and ongoing future forecasts from the National Oceanic and Atmospheric Administration (NOAA) to develop algorithms that can predict and simulate wind patterns to help with balloon navigation. The balloons will be steered by adjusting the helium to air ratio to raise or lower them to the stratospheric level where the wind is blowing in the direction Google needs them to go. They will be hitching rides on the wind, making them both solar and wind powered in a sense.

Google has developed an operations system they call Mission Control to constantly monitor, track and steer the balloons, and even alert nearby air traffic controllers of their presence when they're ascending to the stratosphere or descending to land. Their navigation software has been improved over time, from sending commands just once a day to every 15 minutes. Mission Control can recalculate the balloon flight paths every minute. The Loon team has also improved their ability to direct the balloons to specific locations, from a few hundred meters initially to a now much more accurate few hundred kilometers. Navigation needs to be automated as much as possible to enable control of thousands of balloons at a time to keep the networks from breaking, but there will still be people using the Mission Control software to keep tabs and control things manually, if need be.

Google can bring the balloons back down to the ground for recovery by releasing gas from the envelope. Gas may also be vented automatically if the balloon is in danger of bursting. A parachute will automatically deploy if the balloon drops too fast. Google plans to retrieve the balloons and equipment whenever possible to reuse or recycle the components.

The LTE networking equipment attached to the balloons will work on existing phone companies' cellular spectrums and allow the balloons to communicate directly with cell phones and towers on the ground, eliminating the necessity for installing special ground antennas. Google will form partnerships with local cell companies so people can connect through LTE-enabled mobile devices. Special Loon SIM cards will be necessary to connect to the network.

Preliminary testing, dubbed the Icarus tests, began in August 2011. Project lead Rich DeVaul and his team released four latex balloons carrying Linux computing equipment and a WiFi router from the San Luis Reservoir in California. They followed them in a vehicle equipped with antennas, a WiFi card and a spectrum analyzer to test the signal. Other similar tests followed until they were ultimately able to pass a signal from one balloon to another and get an Internet connection in the car. The equipment was reportedly in a styrofoam cooler for some of the early tests.

In 2012, the team name was changed to Daedalus (Icarus's dad). DeVaul became Chief Technical Architect because he preferred to work on the technical stuff, and Mike Cassidy took over as project lead. They hired aerospace engineers, network engineers, mapping specialists, energy specialists, at least one balloonist, military vets and textile experts (including seamstresses) for designing, testing and sewing the balloons. In 2012, they started working with company Raven Aerostar, which manufactures balloons for NASA among others, to help perfect the balloons.

To increase chances of equipment recovery, the test equipment had the words "harmless science experiment" emblazoned on it with a number to call for a reward (but no mention of Google, since it was still a secret project at that point). In October 2012, one of the test balloons apparently sparked some UFO sighting reports in Kentucky and eventually floated to Canada, where it was lost.

The first official pilot tests occurred in June 2013, with thirty balloons released from New Zealand's Christchurch area. They went about 15.5 miles (25 kilometers) up, and each carried around 22 pounds of equipment that communicated wirelessly with special pre-installed bulbous ground-based antennas. There were around 50 testers in all, among them the Nimmo family and the MacKenzie family, who were among the first people to connect to the Internet via a balloon network. The testers were connecting at 3G speeds.

Further tests have been performed in California's Central Valley, Australia, Chile and Brazil, among other places. In June 2014, Linoca Gayoso Castelo Branco, a school in Brazil, was able to connect to the Internet for the first time ever using Project Loon's LTE radio equipped balloons in conjunction with a ground-based antenna on the school roof [sources: Levy, Simonite]. The next step for Google is getting hundreds of balloons up in a ring around the planet to test continuous service in areas in the Southern Hemisphere. The company has some issues with getting overflight permissions in a lot of places, so it's largely testing in the Southern Hemisphere where there aren't as many obstacles of that nature [source: Verge].

In July 2015, it was announced that Google is partnering with the country of Sri Lanka to provide the entire country of 25,000 square miles (64,750 square kilometers) and around 22 million people (most of whom aren't currently online) with Internet access via Project Loon balloons, possibly by early 2016 [sources: Gershgorn, Lavars, Yahoo].

One of the Loon balloons crashed into a palm tree in a residential yard in a Los Angeles, California suburb in September 2015, not too far from its intended landing site [source: Collman]. No one was hurt in the minor incident.

There are lots of places where Internet service is subpar or nonexistent, or where a lot of people simply can't afford what's available. In 2011, when Project Loon began, the International Telecommunication Union reports that there were 2.2 billion people on the Internet. In 2015, that number has risen to approximately 3.2 billion [sources: Davidson, ITU]. Despite the hefty increase, this still leaves around 4 billion people without Internet access.

Even some people with access don't have quality, uninterrupted high-speed broadband. Connectivity from the sky can provide service in areas that normally have issues, such as mountainous terrain, as well as places that the infrastructure of the Internet has not fully reached. Networks of balloons should be far easier and cheaper to unleash in remote places, including in developing nations, than laying wires and putting up cell towers and other expensive equipment, or using extremely expensive communications satellites. Networks of Google balloons could also be used in emergencies, for instance to get Internet service back up quickly after a natural disaster has damaged ground equipment.

Cellular carriers have shown interest in renting access to Google Loon networks. This could enable them to reach new customers and to provide better service at faster speeds in areas they already cover. It won't be free, but there's hope that some of the cost savings could be passed on to customers in the form of lower prices. Google has already partnered with Vodafone in New Zealand, Telstra in Australia and Vivo and Telebras in Brazil for testing.

Project Loon could be a real boon for society, in an age where being connected to the rest of the world has tremendous benefits. Getting everyone on the planet online would also provide benefits to Google, which relies heavily on revenue from online ads and services. And again, the company would receive payments for access to the Loon networks.

In 2014, Google purchased another solar-powered, high-altitude drone company (reportedly out from under Facebook) called Titan Aerospace to help with several of their projects including Project Loon and mapping, and they bought satellite company Skybox Imaging and invested in spaceflight company SpaceX. SpaceX is seeking permission to launch thousands of small satellites into low orbit to provide high-speed Internet to the world.

Google isn't the only company trying to get Internet to people via the sky. Facebook started their Connectivity Lab with the purpose of getting low-cost Internet to more people all over the world using technologies such as satellites and drones. They bought a solar-powered, high-altitude drone company called Ascenta in 2014, and hired tech experts from places like NASA.

Being able to connect to the Internet gives people access to all the resources the World Wide Web has to offer, from communication to education to business opportunities. Any number of businesses can gain vital information and new sources of materials and products. People in areas with few or no healthcare workers could potentially receive virtual medical care. Teachers and students can instantly get access to supplemental classroom materials, and people without access to schools can read textbooks or take classes online. Young future scientists and inventors can find ideas, resources and possibly even collaborators online.

Access can improve an area's economy. According to Google Loon's project lead Mike Cassidy, increasing a country's Internet penetration by 10 percent results in about a 1.4 percent increase in GDP per year [source: Valve].

Google hopes to have Project Loon providing commercial service by late 2016.