Researchers from NASA's Marshall Space Flight Center, Huntsville, Alabama, and Dryden Flight Research Center, Edwards, California, and the University of Alabama in Huntsville have flight-demonstrated a small-scale aircraft that flies solely by means of propulsive power from an invisible, ground-based infrared laser.
Flights of the lightweight, radio-controlled model airplane inside a large building at NASA Marshall are believed to be the first time that a plane has been powered only by laser energy. The demonstration was a key step toward the capability to beam power to an aircraft, allowing it to stay in flight indefinitely -- a concept with potential for the scientific community as well as the remote sensing and telecommunications industries.
During the flight demonstration in September 2003, an engineer manually directed the laser's energy beam from a central platform at infrared-sensitive photovoltaic cells carried on a panel on the bottom of the aircraft to power the motor as it flew circles inside the large building.
A similar demonstration using a large theatrical spotlight was flown in the summer of 2002 at NASA Dryden, proving that beamed visible light could be used to power the 11-ounce aircraft. The spotlight beamed power to a solar panel attached underneath the aircraft frame that converted the light into electrical energy for the tiny, six-watt motor.
An aircraft was flown using microwave energy 20 years ago, but these were the first known demonstrations of beamed light energy to fly an airplane. The lightweight model aircraft used for these demonstrations was controlled using the same over-the-counter radio control instrumentation available to model aircraft hobby enthusiasts.
Beaming power via a laser to an aircraft is just one concept being explored by NASA to enable solar-electric powered aircraft to fly through the night when solar energy is not available. Another promising technology that is well along in development would use either regenerative or non-regenerative fuel cell systems to achieve the same purpose.
