Ever since the dawn of powered flight, it has been necessary for all
aircraft to carry onboard fuel – whether in the form of batteries, fuel,
solar cells, or even a human “engine” – in order to stay aloft.

But a team of researchers from NASA’s Marshall Space Flight Center in
Huntsville, Ala., NASA’s Dryden Flight Research Center at Edwards,
Calif.,
and the University of Alabama in Huntsville is trying to change that.

They have now chalked up a major accomplishment… and a “first.” The
team
has developed and demonstrated a small-scale aircraft that flies solely
by
means of propulsive power delivered by an invisible, ground-based
laser. The
laser tracks the aircraft in flight, directing its energy beam at
specially
designed photovoltaic cells carried onboard to power the plane’s
propeller.

“The craft could keep flying as long as the energy source, in this case
the
laser beam, is uninterrupted,” said Robert Burdine, Marshall’s laser
project
manager for the test. “This is the first time that we know of that a
plane
has been powered only by the energy of laser light. It really is a
groundbreaking development for aviation.”

“We feel this really was a tremendous success for the project,” added
David
Bushman, project manager for beamed power at Dryden. “We are always
trying
to develop new technologies that will enable new capabilities in
flight, and
we think this is a step in the right direction.”

The plane, with its five-foot wingspan, weighs only 11 ounces and is
constructed from balsa wood, carbon fiber tubing and is covered with
Mylar
film, a cellophane-like material. Designed and built at Dryden, the
aircraft
is a one-of-a-kind, radio-controlled model airplane. A special panel of
photovoltaic cells, selected and tested by team participants at the
University of Alabama in Huntsville, is designed to efficiently convert
the
energy from the laser wavelength into electricity to power a small
electric
motor that spins the propeller.

The lightweight, low-speed plane was flown indoors at Marshall to
prevent
wind and weather from affecting the test flights. After the craft was
released from a launching platform inside the building, the laser beam
was
aimed at the airplane panels, causing the propeller to spin and propel
the
craft around the building, lap after lap. When the laser beam was turned
off, the airplane glided to a landing.

The team made a similar series of demonstration flights in 2002 at
Dryden,
using a theatrical searchlight as a power source. The recent flights at
Marshall are the first known demonstration of an aircraft flying totally
powered by a ground-based laser. The demonstration is a key step toward
the
capability to beam power to a plane aloft. Without the need for onboard
fuel
or batteries, such a plane could carry scientific or communication
equipment, for instance, and stay in flight indefinitely. The concept
offers
potential commercial value to the remote sensing and telecommunications
industries, according to Bushman.

“A telecommunications company could put transponders on an airplane and
fly
it over a city,” Bushman said. “The aircraft could be used for
everything
from relaying cell phone calls to cable television or Internet
connections.”

Laser power beaming is a promising technology for future development of
aircraft design and operations. The concept supports NASA’s
mission-critical
goals for the development of revolutionary aerospace technologies.

Editor’s note: A NASA TV VideoFile on this subject will be broadcast
beginning at 12 noon EDT October 9, 2003. NASA TV is available on the
AMC-9C transponder, C-Band, located at 85 degrees west longitude. The
frequency is 3880.0 MHz. Polarization is vertical and audio is
monaural at
6.80 MHz.

Photos

http://www1.msfc.nasa.gov/NEWSROOM/news/photos/2003/photos03-180.html