"So by controlling the applied voltage of just a few volts, you will be able to control the motion itself," Isaac says. In effect, by switching the current on and off, the wings of the aircraft can be made to flap, much like a bird.
The current will come from highly flexible solar panels — another cutting-edge technology — that form the outer skin of the wings. Many mechanical parts, like motors and hydraulics, are eliminated, thus reducing the chance of failure.
Smooth Sailing Required
So theoretically, it could stay up forever, either guided to its destination by ground controllers, or using onboard sensors to operate independently. Of course, Isaacs isn't counting on it staying up forever.
"If everything works as expected, it could keep on going, but we know that things take place, like weather, and that can be a big factor," he says.
On Earth, for example, the craft would have to stay out of the jet stream, where powerful winds would rip it to pieces. And on Mars, there's those sand storms. But at least clouds won't be a problem. It should operate comfortably at 30,000 feet, or more, staying mostly above the clouds where it can capture those solar rays.
It won't be able to carry the kitchen sink, because its very nature will keep it fairly small, probably less than 15 to 20 feet in wingspan.
"The basic idea of flapping wings obviously limits the size," Isaac says. A large craft would not be able to handle the considerable stresses and strains caused by flapping wings.
"It won't be feasible to have a large structure with flapping wings," he says. "That limits the size of the payload, so it won't be for a manned vehicle."
Lee Dye’s column appears weekly on ABCNEWS.com. A former science writer for the Los Angeles Times, he now lives in Juneau, Alaska.