Issue date: 3/3/04 Section: Sci/Tech

By Chris Griffin

It would seem the researchers at NASA are always up to something. Although recently, they may have figured out a new way to keep something up. A team of scientists at the NASA Dryden Flight Research Center has developed a way to power aircrafts with an invisible ground-based laser, enabling planes to stay in flight for extended periods of time.
The birth and evolution of the powered aircraft have changed the world, and just like any other greatly utilized technology, with each new step came the desire for the next.

Almost a century ago in December 1903, Orville and Wilbur Wright accomplished the unthinkable. They designed and constructed the world's first powered "flying machine." Upon manned flight, they marked the first time that a machine under the control of a pilot had gone airborne, sustained flight and safely returned to the ground.

Mankind was never the same. Man had taken to the skies, and eventually, powered flight was a mainstay for the military and commercial industry.

Obviously to stay aloft, airplanes, as they came to be called, needed some sort of energy source such as fuel, batteries or solar panels.

The problem with these forms of energy is that they constantly need to be replenished. But Alan Brown, a member of the NASA research team, describes laser-powered flight in a way that suggests the days of refueling may someday end.

"It's like an extension cord in the sky," Brown said. "The plane will fly for as long as the laser is illuminating the photovoltaic panel with energy.

There is no limitation on how long the plane can fly."

The plane has an electric motor, and a photovoltaic panel is directly connected to it. A laser beam with enough intensity and correct wavelength is directed towards the photovoltaic panel as the plane is in flight. The light energy from the laser is converted into electrical power, and that power is used to run the motor.

"If the laser is removed from the panel, the motor will stop providing thrust, and the plane will glide to the ground," Brown said. "Actual experience was that the plane was flown until the operator tracking (pointing) the laser at the plane got too tired to continue and called for the flight to end."

At this point, NASA has only built and tested a small-scale prototype aircraft. It has a wingspan of five feet, and including the photovoltaic panel, weighs about 11 ounces. During testing, the plane was hand-launched from a height above the ground inside a large building. It successfully flew in tight circles before gliding down to a triumphant landing.

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