Tuesday, September 23, 2008

Forget Rockets, Think Elevators.

I've never been a huge fan of elevators (I got stuck in one when I was about 7, and apparently still can't get over the trauma...), but the prospect of hopping into a carriage and gliding up to the stars is tantalizing. The idea is more than just sci-fi reverie; in a few weeks an international group of researchers, engineers, physicists and potential astronauts will gather in Japan to draw up a proposal and timeline for building the world's first space elevator ( an artist's impression of the platform of the proposed space elevator is shown above).

According to the Times, the Japan Space Elevator Association (JSEA-I'd link, but the site is in Japanese) says the elevator would run on 22,000 mile long, flat, ribbon-like cables, and would cost about a trillion yen, or $9 billion. The Japanese say the price tag is fairly cheap-considering the amount of research and advances in materials science and engineering that the project requires, not to mention the planning and construction costs.

Instead of using an enormous amount of fuel and energy to blast yourself into space, imagine climbing through the sky like you would glide over land on a cross-country train. In fact, the JSEA says the elevator's ascent could be powered much like Japan's high speed bullet trains. Running on electrical power, the elevator would carry both passengers and cargo or even pollution like radioactive waste. Shuichi Ono, chairman of the JSEA claims that overcoming Earth's gravity with the space elevator would require "perhaps 100 times less" energy than launching a space shuttle.

Most people think of buildings when they think of elevators, but constructing the mother of all skyscrapers into space isn't exactly feasible. The crux of the space elevator would be the ultra light and incredibly strong ( and yet to invented) cables bolted to the ground on one end, and stretched up beyond the atmosphere to a satellite docking station on the other. The station would be right over the same spot on Earth, this is called geosynchronous orbit.

Of course, the cables would have to be resilient enough to withstand all bombardments inside and outside the atmosphere. And scientists will need twice the amount of cable required for the elevator to travel from the ground to the stationary satellite, in order to maintain a counterweight so that the cable maintains its tension.

Researchers are betting on carbon nanotubes as the best material for manufacturing the cables. According to a Japanese professor of precision machinery engineering (and JSEA director), the cable would need to be about four times stronger than what is currently the strongest carbon nanotube fiber, or about 180 times stronger than steel.


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