Friday, March 28, 2008

Space elevators face wobble problem

It has been readily admitted that a space elevator could slash the cost of space travel. But a new study suggests that even if we can get past the technological problems of building the gigantic structure, an even bigger challenge would be keeping it standing. It now appears the structure would need to include built-in thrusters to stabilize itself against dangerous vibrations. These vibrations can be generated by all sorts of forces. Gravitational forces from the Sun and Moon, as well as pressure from gusts of solar wind. Such oscillations could potentially make it veer into space traffic, including satellites and bits of space debris. A collision could cut the tether and wreck the space elevator. Previously considered methods of dampening the oscillations were to make the Earth-based anchor for the tether movable, there-by counter acting the vibrations. New research suggests that this may not be enough, while others suggest that this line of research has not shown enough quantitative analysis of the issue and disagree on the effectiveness of the ground based dampening. There has been some thought given to Earth's magnetic field naturally weaken any vibrations, though unlikely that it alone would cancel out the vibrations. Augmenting the Earth's magnetic field with electric currents through the cable might obviate the need for thrusters. All things considered however, researchers still feel that the space elevator idea is worth pursuing.
Here is a short video demonstrating the effects

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