The US Army is developing drones that can be charged by lasers in mid-air

Drone

Even the most power-efficient drones can only fly for about half an hour without needing a charge, but the United States Army is working on a novel solution – and it involves lasers.

According to New Scientist, researchers are experimenting with firing beams at photovoltaic cells (solar panels), giving them a boost from up to 500 meters away. If such a system could be fitted to a drone, it would remove the need for docking and charging, allowing the craft to stay aloft for hours on end.

Unlike PHASA-35 – a high-altitude drone designed by BAE Systems and Prismatic that will stay airborne by charging its photovoltaic cells above the clouds – the US military's experiment is designed for smaller craft that fly lower and are mostly used for intelligence-gathering.

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It's an ingenious idea, but there are a few potential pitfalls. Firstly, any light energy not converted to electricity will be turned into heat, which could melt the drone mid-flight. Then there's the safety issue of other objects straying into the beam – including people, birds and aircraft.

The US Army hopes to mitigate these problems by developing more accurate targeting, and finding more effective ways to dissipate thermal energy. It's currently working on a working model that will demonstrate the process ground-to-ground, and intends to have a ground-to-air system operational by 2020.

It's highly unlikely we'll see such remote charging technology in consumer drones any time soon though. Flying lessons are already mandatory in many countries – and that's without throwing high-energy lasers into the equation.