Laser Beam Powers UAVs to Stay in Flight
Conventional unmanned aerial vehicles (UAVs) are limited in their flying time because of the fuel they carry or a short battery life. With the help of the sun, UAVs can stay up a bit longer – like Qinetiq’s Zephyr that has been able to fly for 82 hours. However, the sun doesn’t shine all the time, as we know, and solar powered UAVs can have a hard time staying up at night.
The company LaserMotive, a Seattle-based research company, believes they can keep an electric aircraft in the air forever – without the sun or any fuel – just using energy from lasers.
LaserMotive is developing a laser power beaming system to transmit electricity without wires for applications where wires are either cost prohibitive or physically impractical.
The company demonstrated a laser-powered model helicopter at the recent AUVSI Unmanned Systems Conference. The tethered, radio-controlled model helicopter was powered by an array of semiconductor-diode near-infrared lasers, which produced laser beams that were then focused down to a single beam seven centimeters wide.
Sample of a near-infrared 1,000 W laser diode array, less than 3 inches across.
The beam, which will not damage eyes, tracked the helicopter automatically and illuminated the helicopter’s photovoltaic (PV) cells, which were optimized for the laser’s wavelength. The PV cells then converted around 50 percent of the laser power to electricity, providing just a few watts, but enough to keep the rotors spinning.
LaserMotive took home a $900,000 prize in the NASA-sponsored Power Beaming competition. They beamed power to a robot that climbed a 900-meter cable dangling from a full-scale helicopter. The technology could help power space elevators to lift objects thousands of kilometers into orbit.
In other scenarios, a craft could hover for long periods over a laser base, or fly between a series of laser bases. In the longer term, lasers could power remote ground-based sensors or supply emergency power during disasters.
By demonstrating the physical and economic viability of laser power beaming, LaserMotive has big plans for extending flight duration in space and on Earth.
Source: T.J. Nugent and J.T. Kare, LaserMotive, LLC.