The Audacious Space Elevator

Fiber materials such as graphite, alumina, and quartz have exhibited tensile strengths greater than 20 GPa (Giga-Pascals, a unit of measurement for tensile strength) during laboratory testing for cable tethers. The desired strength for the space elevator is about 62 GPa. Carbon nanotubes have exceeded all other materials and appear to have a theoretical strength far above the desired range for space elevator structures. "The development of carbon nanotubes shows real promise," said Smitherman. "They're lightweight materials that are 100 times stronger than steel."

The second technology thrust was the continuation of tether technology development to gain experience in the deployment and control of such long structures in space.

Third was the introduction of lightweight, composite structural materials to the general construction industry for the development of taller towers and buildings. "Buildings and towers can be constructed many kilometers high today using conventional construction materials and methods," said Smitherman. "There simply has not been a demonstrated need to do this that justifies the expense." Better materials may reduce the costs and make larger structures economical.

Fourth was the development of high-speed, electromagnetic propulsion for mass-transportation systems, launch systems, launch assist systems and high-velocity launch rails. These are, basically, higher speed versions of the trams now used at airports to carry passengers between terminals. They would float above the track, propelled by magnets, using no moving parts. This feature would allow the space elevator to attain high vehicle speeds without the wear and tear that wheeled vehicles would put on the structure.

Fifth was the development of transportation, utility and facility infrastructures to support space construction and industrial development from Earth out to GEO. The high cost of constructing a space elevator can only be justified by high usage, by both passengers and payload, tourists and space dwellers.

During a speech he once gave, someone in the audience asked Arthur C. Clarke when the space elevator would become a reality.

"Clarke answered, 'Probably about 50 years after everybody quits laughing,'" related Pearson. "He's got a point. Once you stop dismissing something as unattainable, then you start working on its development. This is exciting!"