Aviation innovator Paul MacCready once envisioned unmanned vehicles finding jobs as versatile aerial science labs (see Discover, September 1999). It's happening. In the last six months, various remotely operated aircraft began gathering and transmitting scientific data from up to 12 miles above the ground. In June and July, for example, MacCready's Pathfinder Plus solar-powered flying wing served as a mobile broadcast tower, successfully relaying test signals for HDTV, cell phones, and the Internet. In August NASA's twin turbo Altus II made 11 flights through heavy storms to measure electrical charges that lead to lightning. And in September, Pathfinder Plus spent half a day soaring above a coffee plantation in Hawaii, collecting and transmitting nearly 300 color images, including the one at right.
At just a few million dollars each, these aircraft would not only cost much less than satellites but also produce higher resolution images, thanks to their position in the sky—lower than satellites but higher than airplanes. And they put no pilot at risk. "When we started out, we had some idea of what these craft could be used for," says John Del Frate, project manager of solar-powered aircraft at NASA's Dryden Flight Research Center. "Now we're starting to see the customers come out of the woodwork."
Photograph courtesy of NASA/Dryden Flight Research Center.