For the price of the laser and the solar cells, you could have bought a second drone (maybe even a third). Instead of periodic "refueling", you just periodically swap drones.
Is there a flaw in this criticism?
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:
