Now a team at Lehigh University, led by engineering professor Joachim Grenestedt, is refining the concept. Working with funds from their school and the National Science Foundation, the team is developing a large unmanned vehicle designed for perpetual flight. They recently completed a 21-foot-long wing of carbon-fiber composite designed to fly in jet streams above 20,000 feet and able to withstand speeds of up to 300 mph and forces of up to 20 Gs (dynamic soaring can be tough on a wing). Later this year, the team will carry out low-altitude tests with a model sailplane. If all goes well, Grenestedt says, he will aim his craft, called the JetStreamer, into the jet stream, where winds can reach 200 mph.