Sun, Sep 14, 2003 - Page 6 News List

Stairway to heaven a reality as space elevator talks begin


If climbing a stairway to heaven sounds like too much hard work, then a conference of 70 scientists and engineers opening in Santa Fe, New Mexico, yesterday may offer hope of a more leisurely way into space.

In two days of discussions, the scientists aim to turn into a reality an ambition that has been around for at least a century: the creation of a space elevator that would deliver satellites, spacecraft and even people thousands of kilometers into space along a vertical track.

Engineers say that recent advances in materials science -- particularly in the development of carbon nanotubes -- mean that such a system, which first gained widespread attention when the science fiction writer Arthur C Clarke described it in his 1979 novel Fountains of Paradise, is no longer pure science fiction.

Clarke -- who once said a space elevator would only be built "about 50 years after everyone stops laughing" -- was due to address the scientists at the Santa Fe conference yesterday by satellite link from his home in Sri Lanka.

The American space agency NASA is no longer laughing. It is putting several million US dollars into the project under its advanced concepts program.

At the heart of a space elevator would be a cable reaching up as far as 100,000km from the surface of the Earth. The earthbound end would be tethered to a base station, probably somewhere in the middle of the Pacific ocean. The other end would be attached to an orbiting object in space acting as a counterweight, the momentum of which would keep the cable taut and allow vehicles to climb up and down it.

A space elevator would make rockets redundant by granting cheaper access to space. At about a third of the way along the cable -- 36,000km from Earth -- objects take a year to complete a full orbit.

If the cable's center of gravity remained at this height, the cable would remain vertical, as satellites placed at this height are geostationary, effectively hovering over the same spot on the ground.

To build a space elevator, such a geostationary satellite would be placed into orbit carrying the coiled-up cable.

One weighted end of the cable would then be dropped back towards Earth, while the other would be unreeled off into space.

Mechanical lifters could then climb up the cable from the ground, ferrying up satellites, space probes and eventually tourists.

No scientist has yet succeeded in making a material, which many expect will be made out of carbon nanotubes, strong but light enough to make the cable, but Rodney Andrews, a carbon nanotube expert from the University of Kentucky will tell the conference: "Until some of the basic science concerning how to connect nanotubes together and transfer load between them in a composite is understood it will remain elusive, but a lot of progress is being made."

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