An invasion of Mars begins in December. Spacecraft from the U.S. and the European Union will descend upon the Red Planet. Rovers will creep across the surface, collect soil samples, and look for the thus-far elusive signs of life—past or present.

To really cover the territory, however, you need some kind of aircraft. And in the thin Martian atmosphere, getting anything to fly means using wings so long and fragile that they probably wouldn't make it to Mars in one piece.

A group of engineering students at the University of Kentucky in Lexington say they've found a way around that problem: Create inflatable fabric wings that "pop out" when the aircraft arrives at Mars and then harden to retain their shape. It's an audacious plan, one that has never before been tried. And to verify that it would work, the students would need to send a prototype to the edge of space.

"We wanted to do something that would get our students interested in aerospace engineering," said Suzanne Smith, professor of mechanical engineering at the University of Kentucky. For several years, she has been an advisor in the Kentucky Space Grant Consortium program, which works to encourage students to study aerospace engineering.

In July 2002, Smith, colleague Jamey Jacob, incoming senior Justin Kearns, and others put their heads together to draw up a realistic research project for NASA's Space Grant Aerospace Workforce Development Program, which is designed to give engineering students experience working on a next-best-thing-to-real aeronautics project. And because the student projects develop real, tangible bits of technology, rather than science fair demonstrations, students involved in the workforce development program can get access to industry and NASA facilities that would remain otherwise inaccessible.

Developing a set of self-hardening, inflatable wings wasn't easy. Smith said inflatable wings have been tested before—chiefly for defense applications—but they retained their shape only through air pressure. And though pressurized structures may be able to support heavy loads, they are susceptible to buckling. The Kentucky wing needed some way to harden itself against lateral stresses.

The team hit upon a novel solution: coating the fiberglass fabric airfoil with a resin that hardens when exposed to ultraviolet light. (Because it lacks an ozone layer, Mars is bathed in UV light.) That solution begged two outstanding questions: Would the ribbed profile of the wing be aerodynamically sound? And could the coating harden fast enough to avoid disaster?

The students spent the fall consulting with ILC Dover, maker of NASA spacesuits and the airbags used by the Mars landers, and by December were ready to test the wing, designed by student Michiko Usui, in a wind tunnel. In spite of the wing's quilted profile (Dover made it from hand-sewn strips), it had a much better aerodynamic profile than expected. "The bumpy profile is an advantage, because it keeps the airflow from detaching," Smith said.

But to determine how quickly the wing would harden in the Martian atmosphere, the students would have to test it in a Mars-like environment: the thin, UV-drenched air at an altitude of some 90,000 feet.

In January, 42 participating students broke into 10 teams to design and build various elements for a flight test of the Baseline Inflatable Glider Balloon-Launched Unmanned Experiment (BIG BLUE). "It was an incredible rush job," said Kearns, who became the student leader. "But we split the work into small groups and did the work in parallel, and that helped us meet the deadline." The complex task of integrating the mechanical and electrical systems was led by electrical engineering professors Bill Smith and James Lumpp.

Even small commercial rockets are expensive to charter and their performance is often undependable. But Edge of Space Sciences, a club in Denver, launches high-altitude balloons once a month and was willing to carry the test plane along on their May 2003 flight.

Justin Kearns remembers being a little nervous as the balloon was released. "But as it flew up with the glider, we knew the next time we'd see it is after it had been at the edge of space," he said.

The flight went flawlessly: The craft cut free and parachuted down, the wings deployed, the surface hardened, and the radio and video telemetry sent all the data in real time back to the ground crew. (For a time, in fact, the Kentucky group's telemetry was the only way to track the balloon.) Mission accomplished.

Although many of the students working on the project have graduated, next year's group is expected to test the craft in free flights in 2004.

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