Thinking Tech

Powered only by lasers, hovering drone flies for twelve hours straight

Powered only by lasers, hovering drone flies for twelve hours straight

Posting in Design

Ground-based lasers could soon keep UAVs aloft indefinitely.

Twelve hours after it rose from the floor, the sprightly, toylike Pelican quadrocopter gently lowered itself back down, bathed in a warm, multicolored glow. What it had done--hovered in place for half of a day--was unremarkable. But how it did that--with the equivalent of 250,000 laser pointers worth of focused light power--represents a broad step forward for the fledgling field.

LaserMotive's technology is fundamentally like a typical solar panel system. The laser beam is captured and focused onto a photovoltaic panel by a series of mirrors. As with many other solar devices, the Pelican has a small reserve battery, just in case the laser is obstructed for a short time. The main difference? This solar power is concentrated and directed, and has a massive potential range.

As it exists, the Pelican drone is distinctly experimental. A super-light, quad-rotor hobby craft that runs off of a purpose-built laser, the Pelican is merely a starting point for extrapolation--something its maker, LaserMotive, is glad to engage in:

Laser power links enable two types of operation.  One is near-continual powering of the UAV, which would therefore need only a very small energy storage device on board. The other is intermittent recharging when the UAV returns to a designated area within reach of the base station; in this case the UAV would need larger onboard energy storage.  In both cases, the laser power link improves on-station time and reduces personnel requirements during UAV mission cycles.

The most compelling of the above possibilities seems to be the intermittent recharging scenario: A drone that could be "refueled" simply by entering a five-mile charge radius for a few hours has obvious and immediate applications.

The Pelican is the second high-profile breakthrough for LaserMotive, which won a $900,000 prize from NASA for the successful demonstration of a laser-powered space elevator device. (Their robot was able to climb to a height of nearly half a mile, at a rate of 3.73 meters per second.)

Before LaserMotive's technology can be built into battle-ready (or space-ready) drones or elevators, they'l need to overcome a few hurdles--most pressingly, that the transfer of power from source to craft is extremely inefficient. Using arrays of near infrared laser diodes, about 50% of the energy is lost in the DC-to-light phase, only to diminish much, much further as it travels through the craft's solar cell and into its motors or batteries. This could be particularly problematic for mobile, truck-mounted charging stations, as they'd need to carry a tremendous amount of energy in the form of fuel or batteries.

Once the technology is mature--and this will likely be more than a few years--LaserMotive has big plans for the technology. UAVs and space elevators are fine and good, co-founder Jordin Kare told MSNBC, but laser power gets truly exciting when you consider its outermost potential. "I've actually done a design for powering a lunar base from Earth."

Here's a video of the Pelican in action:

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John Herrman

Contributing Editor

Contributing Editor John Herrman is a freelance writer based in New York City. He is also contributing editor at Gizmodo. He holds a degree from the University of Edinburgh. Follow him on Twitter. Disclosure