Google has announced it is on course to have enough internet-beaming balloons in the stratosphere to form a ring over part of the world in 2016.

The declaration coincides with the announcement that three of Indonesia’s mobile networks intend to start testing Project Loon’s transmissions in 2016.

Sri Lanka previously signed a separate agreement signaling its wish to be another participant in the giant helium balloon-based scheme.

Google first revealed its super pressure balloon plan in June 2013, when about 30 of the inflatable plastic “envelopes” were launched from New Zealand.

Beneath each lighter-than-air balloon are hung: two radio transceivers to receive and send data streams, plus a third back-up radio; a flight computer and GPS location tracker; an altitude control system, which is used to move the balloon up and down to find winds that will take it in the desired direction; solar panels to power all the gear.

Photo Google

Because each balloon only provides connectivity to a ground area 25 miles in diameter below it, the initial ring will be limited to a relatively small part of the planet as it circles a section of the Southern Hemisphere.

Super pressure balloons are made out of tightly sealed plastic capable of containing highly pressurized lighter-than-air gases.

The aim is to keep the volume of the balloon relatively stable, even if there are changes in temperature.

This allows them to stay aloft longer and be better at maintaining a specific altitude than balloons which stretch and contract.

In particular, it avoids the problem of balloons descending at night when their gases cool.

The concept was first developed for the US Air Force in the 1950s using a stretched polyester film called Mylar.

The effort resulted in the GHOST (global horizontal sounding technique) program which launched superpressure balloons from Christchurch, New Zealand, to gather wind and temperature data over remote regions of the planet.

Over the following decade, 88 balloons were launched, the longest staying aloft for 744 days.

More recently, NASA has experimented with the technology and suggested superpressure balloons could one day be deployed into Mars’s atmosphere.

Google suggests that Project Loon would be a cheaper solution than installing fiber optic cables or building mobile phone masts across all of Indonesia’s islands, which contain jungles and mountains.

The advantage of a balloon-based system over satellites is that it should ultimately be cheaper to maintain – at least, if all the technological challenges can be overcome.

Google is, however, considering other options.

It is also pursuing a separate effort codenamed Titan, which aims to use solar-paneled drones to provide the internet to unconnected parts of the world.

Facebook is also developing a similar drone-based scheme.