Laser power beaming: A bright new idea for flight

Space exploration is limited by a lack of cosmic petrol stations. But what if we could fuel a craft from earth? Mark Piesing discovers the world of laser power beaming

While the Future of Flight Aviation Centre near Seattle might be a world away from Kitty Hawk where the Wright brothers flew their first powered aeroplane, the flight of the Pelican last October might just become as important for space exploration as the Wrights' first forays were for manned flight. The record-breaking 12-hour beamed-energy-powered flight at the Centre was just one of three world records and six scientific firsts that the Pelican, a remotely controlled quadrocopter built by the German company Ascending Technologies, achieved that day as it turned science fiction into fact.

For more than 25 years scientists have been researching the technology required to convert electricity into light and beam it up to the sides of spaceships, where special solar cells then convert it back into electricity. It is a technology intimately connected to Arthur C Clarke's futuristic vision of a "space elevator", in which lasers beamed energy to cable-climbing robots, enabling them to shift cargo from the Earth's surface into orbit by means of a giant cable stretching into space.

While a space elevator on Earth may still be a lifetime away, for Tom Nugent Jr, president of LaserMotive, the potential impact of laser power beaming is nonetheless "enormous" as the technology becomes a "ready-to-go" reality. LaserMotive won the 2009 Nasa power beaming compet- ition, worth $900,000 (£550,000), by using laser power beaming to drive a small robot up a kilometre of cable dangling from a helicopter. The company also supplied the power beaming kit for the Pelican.

"Not only does laser power beaming offer an endless source of power for air and spacecraft, it opens up new capabilities, as they would never have to land. As lasers have become more efficient, cheap and powerful, so it has become a viable business proposition," says Dr Nugent.

So while the frail Pelican looks more like the Wright Flyer than an interplanetary spaceship, Dr Nugent believes the drone "represents an important achievement for the future of flight". "The Pelican demonstrated that laser power beaming could power an unmanned aerial vehicle for a very long time."

However, Nasa's Andy Petro is more cautious about this new technology and sees the flight of the Pelican as a "demonstrator of capability". As acting director for Early Stage Innovation he sponsors the power beaming competition that has played an important role in the development of the technology.

"While the basic principles of laser power beaming are understood, the challenge is in the detail, whether extending the distance or the efficiency of the laser. The better the rate at which the solar cells convert light back into electricity the more feasible it becomes," says Petro.

Nugent now has to find a market for this technology, even if it is more War on Terror than War of the Worlds. "Not surprisingly there is a lot interest from inside the US military as one of their biggest needs is to increase the duration of their drones, so that they never need to land. There has been particular interest from the Navy for disaster relief in situations like the Haiti earthquake."

Then there's Nasa's next competition later this year, whose challenge is likely to be to use laser power beaming to drive a lunar buggy deep into a dark crater; and looking further ahead still, "we are already talking to researchers about powering manned aircraft in this way."

Tom Nugent, though, has less than a year to address some of these challenges, as LaserMotive hopes to have a laser beaming system "commercially available next year" and even to have a beamed-energy drone watching over us at the 2012 Olympics.

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