Mobile phone users could receive signals from balloons floating in the stratosphere if a project launched by Google this week succeeds.
Google launched 30 test balloons in New Zealand to test the possibility of having a global network of balloons floating 12 miles above Earth provide internet access and mobile phone signals.
Mike Cassidy, head of the project dubbed Project Loon, said in a blogpost: "We believe that it might actually be possible to build a ring of balloons, flying around the globe on the stratospheric winds, that provides internet access to the earth below.
"It's very early days, but we've built a system that uses balloons, carried by the wind at altitudes twice as high as commercial planes, to beam internet access to the ground at speeds similar to today's 3G networks or faster. As a result, we hope balloons could become an option for connecting rural, remote and underserved areas, and for helping with communications after natural disasters."
The balloons are 15 metres wide and 12 metres tall and filled with helium gas. People connect to the balloon network using a special internet antenna attached to their building. The signal bounces from balloon to balloon, then to the global internet back on Earth.
Cassidy said: "There are many terrestrial challenges to internet connectivity – jungles, archipelagos, mountains. There are also major cost challenges. Right now, for example, in most of the countries in the southern hemisphere, the cost of an internet connection is more than a month's income."