NASA has other challenges aimed at encouraging people to develop the kinds of technologies required to build a space elevator. For instance, the power-beaming Centennial Challenge is focused on the kind of technology required to power the cars up and down the elevator.

While NASA doesn't have an office dedicated to working toward building a space elevator, it has identified a space elevator as one potential avenue for exploring space beyond Low Earth Orbit, said Sam Ortega, a program manager with the Centennial Challenges group at NASA.

He was reluctant to guess when a space elevator could actually begin to be built. "We try not to be narrow-minded and say it won't happen for 150 years. Breakthroughs in technology innovation occur on a daily basis," he said.