Space elevators are incredibly tall theoretical structures that stretch beyond the earth’s atmosphere to transport satellites and shuttles into outer space without the cost and environmental impact of rocket fueled launches. The idea has always been more science fiction than science fact, however a team from King’s College London could change that — they claim that advances in carbon nanotubes could make it ‘theoretically’ possible create a tether that would be strong enough to stretch more than 22,000 miles into space.
The idea of a space elevator is not a new one — In fact, it was theorized as far back as 1895 by a Russian called Konstantin Tsiolkovsky who proposed a free-standing “Tsiolkovsky” tower that would stretch from the Earth’s surface to a ‘counterweight’ somewhere in geostationary orbit.
Mark Miodownik, a materials scientist at King’s College London, announced the new proposal at the Royal Institution’s Christmas lecture which is set to be broadcast on BBC4 at the end of the month. Speaking about the concept of a ‘space elevator’, Miodownik said, “The idea of an elevator into space has been around for some decades now and was popularized by Arthur C. Clarke, the science fiction writer, in his 1979 book The Fountains of Paradise. However the idea was never practical because there was no material strong enough to support its own weight over the huge distance necessary to reach from Earth to space.” “What has changed is the discovery of carbon nanotubes, a form of carbon that can be woven into fibers. They are still under development [and] in theory they are strong enough to reach into space.”
If it was constructed, such a cable would need to be kept under tension by the forces of gravity and outward centrifugal acceleration. In theory, the counterweight, which would keep the whole thing stable, would be a docking and refuelling station for future space missions. In fact, NASA has pledged $3 million over the next five years to research the idea and is working on scale models.
Carbon nanotubes are a modern material with tremendous potential. While they are less than 1/50,000 the width of a hair, when wound together a string the width of a sewing thread could hold the weight of a car. In theory, it could support the 30 tons per square millimetre needed to constructed such an incredible system. Miodownik added, “Carbon nanotubes are still under development but they are the first material we have seen that could be strong enough for this task.”
Via The Sunday Times
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