In a recent Atlantic Cities piece about the maximum size of skyscrapers, they wrote that one big parameter that could limit our upward construction was the construction of elevators to the top of the building. Of course, commentors were quick to point out that the author had neglected to mention the use of space elevators. But how realistic are space elevators anyway.
First, let's back up and explain how a space elevator would, in theory, work. The International Space Elevator Consortium (ISEC) explains it this way:
The Space Elevator is based on a thin vertical tether stretched from the ground to a mass far out in space, and electric vehicles (climbers) that drive up and down the tether. The rotation of the Earth keeps the tether taut and capable of supporting the climbers. The climbers travel at speeds comparable to a fast train, and carry no fuel on board - they are powered by a combination of sunlight and laser light projected from the ground. While the trip to space takes several days, climbers are launched once per day.
In 2005, NASA launched a contest called Elevator:2010, with a cash prize to anyone who developed a space elevator. So far, no dice. But is it even possible? At BBC Future, they're skeptical.
Although the concept is simple, the engineering challenges that have to be overcome are awesome. The secret is to find the right material for the ribbon, which has to be light, strong, flexible…oh, and stretch, without breaking, for some 100,000 km (62,000 miles) – higher than geostationary orbit.
Of course, seemingly impossible feats of engineering have been accomplished before. No one in the 1700's would have ever thought we could have built the Empire State Building. All it takes is some materials engineering advances, and about $50 billion. No problem.
Via: BBC Future
Image: Bruce Irving