Drones Recharged by a Laser Could Fly Forever

DARPA chooses the Silent Falcon as its drone of choice for the laser recharging experiment.

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Silent Falcon

DARPA has chosen a drone for its strange-sounding concept: charging aircraft in midair with laser beams. The concept could lead to unmanned planes that stay aloft indefinitely.

The Defense Advanced Research Projects Agency's laser-powered flying drone works like this: The aircraft has solar panels in the wings, particularly the dorsal wing, and batteries in the fuselage. The batteries provide the initial source of power, but as they drain down, the drone operators aim a laser beam at the solar panels. Regular shots of laser power can recharge the aircraft to the point where it can stay aloft indefinitely.

DARPA’s program is called the Stand-off Ubiquitous Power/Energy Replenishment - Power Beaming Demo (SUPER PBD). The agency has now picked Silent Falcon’s eponymous drone for testing. DARPA will try out the concept by flying the Silent Falcon and shooting a laser down at it from a mountainside.

The ability to recharge a drone with lasers does face some hurdles. For one, lasers lose strength the farther they travel and can be obscured or even blocked by smoke, haze, fog, and rain. DARPA figures it can recharge the drone at up to 6.8 miles, but that maximum will vary under real-world conditions. The team acknowledges there are safety issues with shooting a laser up into the air, which is why, for the test, they’re placing the laser on a hill and pointing downward (though they didn't say whether a drone-recharging laser could start a wildfire during the recharging process).

Nevertheless, if DARPA and Silent Falcon can prove this concept works, they could open the door to even longer-0range drones operating in both the commercial and military sectors. Drones could fly for weeks fulfilling a contract or mission, not landing until the job is done.

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