A team of four students from the University of California-Santa Cruz won the first-place trophy in a national student robotics competition for their design of a solar-powered robot that can climb up a vertical ribbon while carrying a payload. Such a robotic climber would be an essential component of a "space elevator," a concept for transporting material into space via a cable or tether extending from the surface of the Earth into space.
The competition, sponsored by the Aerospace Division of the American Society of Civil Engineers, was held at the 2008 Earth and Space Conference. The four electrical engineering students -- Bill Hogan, Kevin Hichborn, Scott Therien, and Laurel DeMarco -- claimed the Fluor Daniel "Perpetual trophy for collegiate competition in extraterrestrial robotics." The team built the climber as their capstone senior design project. Although it would not be suitable for a real space elevator, the overall concept is the same, they said.
"The concept of a solar-powered climbing machine that attaches to a tether and climbs up is the same as our project. But in a real space elevator, the tether would be different and the climber would have to carry a lot more weight," Hogan said.
The scale of an actual space elevator would be mind-boggling. For the tether to reach geosynchronous orbit, it would have to be 22,236 miles long, Hogan said. In the competition, the robotic climbers went up a 20-foot ribbon of 2-inch webbing.
"The goal of the competition is to stimulate design ideas and get people thinking about how to tackle the problem," Therien said. "So the way we attached the climber to the tether and the mechanism for pulling itself up might be used in a real space elevator."
The project actually grew out of the team's desire to do something involving solar power or renewable energy, Hogan said. Elkaim, a robotics expert, suggested the space elevator competition as an interesting application of solar technology, although it involves an artificial light source rather than the Sun to power the climber. The students worked together on the overall design and problem-solving, while each focused on a different subsystem. For example, DeMarco did all the software programming, Therien and Hogan worked on the solar array, and Hichborn worked on the remote control system. They weren't sure their climber would work until about 10 days before the competition. But in the end it outperformed the other entries, especially in its ability to carry a payload.
"We stopped adding weight when we reached three pounds, which is the weight of the climber, because we were so far ahead of the others," Hogan said.