| 1 | 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. |
| 2 | Engineers at the giant social network say they have built a drone with a 140-foot wingspan that weighs less than 1,000 pounds. |
| 3 | It will use lasers to send internet signals to stations on the ground. |
| 4 | 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. |
| 5 | Facebook rival Google is experimenting with high-altitude balloons and satellites in a programme that has similar goals. |
| 6 | The Facebook laser communications system should be accurate enough to hit a target the size of a dime 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. |
| 7 | "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. |
| 8 | 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. |
| 9 | But the company invited reporters to hear an update on its effort to provide service to about 10% 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. |
| 10 | Facebook's drone was developed in part with engineering expertise that joined the company when it acquired a British aerospace startup, Ascenta, last year. |
| 11 | 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. |
| 12 | The plan calls for using helium balloons to lift each drone into the air, Mr Parikh said. |
| 13 | 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. |
| 14 | At night, he said, they will settle to about 60,000 feet to conserve battery power. |
| 15 | 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. |
| 16 | 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. |
| 17 | That is comparable to fibre networks on the ground but about 10 times faster than standard laser signals, he said. |
| 18 | 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. |
| 19 | 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. |
| 20 | 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. |
| 21 | "We're not going to operate this ourselves," he added. |
| 22 | "We're focused on finding ways to drive the industry to move faster." |