If strong enough carbon nanotubes are developed, it could take around 15 years to build a space elevator.

In addition to the challenges of space junk and materials, elevator enthusiasts face another problem: Many people think the idea is ridiculous. Arthur C. Clarke, a science-fiction author who popularized the idea, is reported to have frequently said that he expects a space elevator to be built about 50 years after everyone quits laughing.

The idea has been around for longer than that by now. This year, Yuri Artsutanov, a Russian engineer born in 1929, attended the conference. While Clarke tends to be the first person people mention when talking about the origin of space elevators, Artsutanov published a paper outlining the concept in 1929. His work went unnoticed outside of Russia, however. Clarke described a space elevator in his 1979 book "Fountain of Paradise" after reading a paper about space elevators published in 1975 by another scientist, Jerome Pearson.

The IDG News Service