The Audacious Space Elevator

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"Yes, ladies and gentlemen, welcome aboard NASA's Millennium-Two Space Elevator. Your first stop will be the Lunar-level platform before we continue on to the New Frontier Space Colony development. The entire ride will take about 5 hours, so sit back and enjoy the trip. As we rise, be sure to watch outside the window as the curvature of the Earth becomes visible and the sky changes from deep blue to black, truly one of the most breathtaking views you will ever see!"

Does this sound like the Sci-Fi Channel or a chapter out of Arthur C. Clarke's, Fountains of Paradise? Well, it's not. It is a real possibility - a "space elevator" - that researchers are considering today as a far-out space transportation system for the next century.

David Smitherman of NASA/Marshall's Advanced Projects Office has compiled plans for such an elevator that could turn science fiction into reality. His publication, "Space Elevators: An Advanced Earth-Space Infrastructure for the New Millennium", is based on findings from a space infrastructure conference held at the Marshall Space Flight Center last year. The workshop included scientists and engineers from government and industry representing various fields such as structures, space tethers, materials, and Earth/space environments.

"This is no longer science fiction," said Smitherman. "We came out of the workshop saying, 'We may very well be able to do this.'"

A space elevator is essentially a long cable extending from our planet's surface into space with its center of mass at geostationary Earth orbit (GEO), 35,786 km in altitude. Electromagnetic vehicles traveling along the cable could serve as a mass transportation system for moving people, payloads, and power between Earth and space.

Current plans call for a base tower approximately 50 km tall - the cable would be tethered to the top. To keep the cable structure from tumbling to Earth, it would be attached to a large counterbalance mass beyond geostationary orbit, perhaps an asteroid moved into place for that purpose.

"The system requires the center of mass be in geostationary orbit," said Smitherman. "The cable is basically in orbit around the Earth."

Pat Rawling The space elevator looking down towards Earth.

Four to six "elevator tracks" would extend up the sides of the tower and cable structure going to platforms at different levels. These tracks would allow electromagnetic vehicles to travel at speeds reaching thousands of kilometers-per-hour.

Conceptual designs place the tower construction at an equatorial site. The extreme height of the lower tower section makes it vulnerable to high winds. An equatorial location is ideal for a tower of such enormous height because the area is practically devoid of hurricanes and tornadoes and it aligns properly with geostationary orbits (which are directly overhead).