Facebook has said it will begin test flights later this year of a solar-powered drone with the wingspan of a Boeing 737, the next stage of its campaign to deliver internet service to remote parts of the world.

Engineers at the giant social network say they have built a drone with a 140-foot wingspan that weighs less than 1,000 pounds. It will use lasers to send internet signals to stations on the ground.

The project is part of a broader effort by Facebook that also contemplates using satellites and other high-tech gear to deliver internet connectivity to hundreds of millions of people living in regions too remote for conventional service.

Facebook rival Google is experimenting with high-altitude balloons and satellites in a programme that has similar goals.

The Facebook laser communications system should be accurate enough to hit a target the size of a dime coin at a distance of 11 miles, said Yael Maguire, director of the unit, which is responsible for drones, satellites and other high-tech communications projects.

“There’s a lot of moving parts here that have to work in concert,” said Mr Maguire, during a press briefing at the company’s headquarters.

Facebook also has a separate but related initiative that works with wireless carriers to provide limited mobile internet service at no cost, in countries where residents are too poor to afford traditional wireless plans.

But the company invited reporters to hear an update on its effort to provide service to about 10 per cent of the world’s population who live in regions where it is not practical or too expensive to build the usual infrastructure for internet service.

Facebook’s drone was developed in part with engineering expertise that joined the company when it acquired a British aerospace startup, Ascenta, last year. Facebook engineering vice president Jay Parikh said the team created a design that uses rigid but light-weight layers of carbon fibre, capable of flying in the frosty cold temperatures found at high altitudes, for an extended period of time.

The plan calls for using helium balloons to lift each drone into the air, Mr Parikh said. The drones are designed to climb to 90,000 feet, safely above commercial airliners and thunderstorms, where they will fly in circles through the day. At night, he said, they will settle to about 60,000 feet to conserve battery power.

Each drone will fly in a circle with a radius of about three kilometres, which the engineers hope will enable it to provide internet service to an area with a radius of about 50 kilometres.

For the plan to work, Facebook’s engineers are also counting on a recent breakthrough they’ve made in laser optics, which Mr Maguire said would allow them to transmit data at up to 10 gigabits per second. That is comparable to fibre networks on the ground but about 10 times faster than standard laser signals, he said.

Facebook is designing the drones to transmit signals from one aircraft to another, so they can relay signals across a broader area on the ground, he added.

While Facebook has built and tested smaller prototypes at a plant in the United Kingdom, it is looking at a site in the United States for testing the full-sized drone, said Mr Parikh, who declined to be more specific.

Facebook hopes to share the technology with telecommunications carriers and development agencies, which it hopes will build and operate the drone networks, Mr Parikh said. “We’re not going to operate this ourselves,” he added. “We’re focused on finding ways to drive the industry to move faster.”

Reuters