Google is launching balloons into near space to provide Internet access to buildings below on the ground, the British Broadcasting Corporation has reported.
About 30 of the superpressure balloons are being launched from New Zealand from where they will drift around the world on a controlled path.
Attached equipment will offer 3G-like speeds to 50 testers in the country.
Access will be intermittent, but in time the firm hopes to build a big enough fleet to offer reliable links to people living in remote areas.
It says that balloons could one day be diverted to disaster-hit areas to aid rescue efforts in situations where ground communication equipment has been damaged.
But one expert warns that trying to simultaneously navigate thousands of the high-altitude balloons around the globe’s wind patterns will prove a difficult task to get right.
Google calls the effort Project Loon and acknowledges it is “highly experimental” at this stage.
Each balloon is 15m (49.2ft) in diameter – the length of a small plane – and filled with lifting gases. Electronic equipment hangs underneath including radio antennas, a flight computer, an altitude control system and solar panels to power the gear.
Google aims to fly the balloons in the stratosphere, 20km (12 miles) or more above the ground, which is about double the altitude used by commercial aircraft and above controlled airspace.
Google says each should stay aloft for about 100 days and provide connectivity to an area stretching 40km in diameter below as they travel in a west-to-east direction.
The firm says the concept could offer a way to connect the two-thirds of the world’s population which does not have affordable net connections.
“It’s pretty hard to get the internet to lots of parts of the world,” Richard DeVaul, chief technical architect at Google[x] – the division behind the scheme – told the BBC.
“Just because in principle you could take a satellite phone to sub-Saharan Africa and get a connection there, it doesn’t mean the people have a cost-effective way of getting online.
“The idea behind Loon was that it might be easier to tie the world together by using what it has in common – the skies – than the process of laying fibre and trying to put up cellphone infrastructure.”
Previous proposals to provide connectivity from the upper atmosphere suggested floating high-altitude platforms that stayed in one place and were tethered to the ground.
Google rejected this idea as it involved fighting the winds, meaning the equipment would have to be large, expensive and limited to a fixed area.
But using free-floating balloons introduces another problem: how to ensure they are where they are supposed to be.
“We didn’t want them to go just wherever the winds took them, we wanted them to go where the internet is needed on the ground,” said DeVaul.
“You have to cause them to move up or down just a little bit through the stratosphere to catch the appropriate wind – which is how we steer them.
“So we have to choreograph a whole ballet of this fleet, and that requires some impressive computing science and a whole lot of computing power.”