Google has announced plans to bring internet connectivity to all of Sri Lanka using hot air balloons. And it might actually work.
According to TechCrunch Project Loon, as it is known, has been in development for some years and the idea is that high-altitude balloons can provide LTE (4G) connectivity to places where it might be tricky to build normal ground-based equipment, Apparently one balloon can provide coverage over a 40km diameter. Apparently it should be possible to connect to the 20km high balloons using a standard (presumably 4G) mobile phone.
What's really smart is that Google plans to send up a whole load of balloons to cover the whole country; the balloons will then use software algorithms to move around and position themselves to ensure consistent coverage, even when wind blows them off course. Google says the project will enable "affordable, high speed internet" for everyone in the country.
Google claims that its balloons can stay airborne for around 100 days, and if they start to fall a parachute will be automatically deployed to ensure a safe landing. The on-board electronics are all powered by solar energy, using steep-mounted solar cells that can generate about 100W of power, which is enough to run during the day, and charge the battery overnight.