A: Not enough to lose sleep over. The space elevator - a permanent structure to economically transport material into space - would extend along a ribbon from an oceanic platform on the equator to an 800-ton counterweight 62,000 miles above the Earth´s surface. Every time the elevator´s âa'¬carâa'¬ ascended with a 15-ton payload, the extended mass would increase the length of an average day by a femtosecond. (It´s the same idea as when a spinning ice-skater puts his arms out to slow down.) Brad Edwards, an expert on the space-elevator concept and president of X-Tech, a developer of high-strength materials, says it´s hardly something to be concerned about. Contemporary events such as melting glaciers (which move millions of tons of water from the poles to the equator) slow down the Earth´s rotation orders of magnitude more than one trip on a space elevator would. Moreover, the elevator would not affect the Earth´s movement around the sun in the slightest. The only real way to significantly hinder the Earth´s rotation would be to deploy approximately 1 percent of its mass. âa'¬You´re talking about launching something that´s roughly the same mass as the moon,âa'¬ Edwards explains. âa'¬That´s just not going to happen.âa'¬. Melissa A. Calderone

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Most of a rocket’s fuel is spent blasting through Earth’s thick atmosphere and out of the planetâa‚¬s strong gravitational field. But here’s an alternate strategy for getting payloads up to space: Construct a 62,000-mile-long cable jutting straight out from the equator, hold it in place with centripetal force, then lift satellites and spacecraft out of the atmosphere with a giant freight elevator. One major hang-up: Cable strong enough to support the system does not yet exist, though it could be made from carbon nanotubes. Shown above is “The Climber” which sill carry the payload.

One of the most promising technologies for the aspiring outer-space commuter is the space elevator. The concept, like quite a few others, was pressed into the public imagination by Arthur C. Clarke, who in his 1979 novel The Fountains of Paradise described a incredibly thin, incredibly strong carbon filament with one end anchored on Earth and the other extending up to a satellite in geostationary orbit. Now, a group of Japanese scientists are convinced that they can build a space elevator more quickly and cheaply than has been believed possible.

Such a cable could convey cargo into space very cheaply and easily. Carriages would travel up and down the cable under modest power, not the vast expenditures of energy that are currently needed to send anything into orbit.

Technology has crept closer to making it a reality: we have geostationary satellites, and carbon nanotubes promise to be strong and light enough to form the filament, if they can be produced in sufficient quantity. A space elevator would be tens of thousands of miles long.

A few initiatives already exist to make a space elevator a reality. Elevator:2010 sponsors annual contests; LiftPort promises to have an elevator built by October 27, 2031, and is selling tickets on it, at $25/ounce.

The Japan Space Elevator Association, a new player in the field anticipates that Japan’s industrial and research power — “using the technology employed in our bullet trains,” according to Association director Yoshio Aoki — will be able to surmount the outstanding obstacles. The carbon fiber, which needs to have 180 times the tensile strength of steel, is currently under development by Japanese textile companies. The total price tag estimated for erecting the elevator is being estimated at just a trillion yen, or about 10 billion dollars.

[Via the Times of London]

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