The concept of an Orbital Tower has appeared in science-fiction literature since the end of the 19th century. The only material strong enough to facilitate such an endeavour from a mechanical-stability point of view would be carbon nanotubes. Another property of the material which can also be used is conductivity, thus leading to significant power production if the tower is put into an orbit around a planet having a global magnetic field.

In 1895 Konstantin Tsiolkovsky, a Russian scientist, looked at the Eiffel Tower in Paris and thought about an orbital tower. He wanted to put a "celestial castle" at the end of a spindle-shaped cable, with the "castle" orbiting the Earth in a geosynchronous orbit. Building from the ground up, however, proved an impossible task (though there are still groups talking about volcanoes as a possible source for a space elevator). It took until 1960 for another Russian scientist, Y.N. Artsutanov, to propose another scheme for building a space tower. In his book "Dreams of Earth and Sky", Artsutanov suggests using a geosynchronous satellite as the base from which to build the tower. By using a counterweight, the cable would be lowered from geosynchronous orbit to the surface of the Earth, while the counterweight was extended from the satellite away from the Earth. Nine years after Artsutanov, an American physicist, Jerome Pearson, designed a tapered cross-section that would be better-suited to building the tower. He suggested using a counterweight that would be slowly extended out to 144 000 km (half the distance to the Moon) as the lower section of the tower was built. His analysis included disturbances such as the gravitation of the Moon, wind and payloads moving up and down the cable. The weight of the material needed to build the tower would have required 24 000 Space Shuttle trips, although part of the material could be transported up the tower when a minimum-strength strand reached the ground.

Later, Pearson thought about building a tower on the Moon. He determined that the centre of gravity needed to be at the L1 or L2 Lagrangian points, which are special stable points that exist about any two orbiting bodies where the gravitational forces are balanced. The cable would have to be 291 901 km long for the L1 point and 525 724 km long for the L2 point. Compared to the 351 000 km from the Earth to the Moon, that's a pretty long cable, and the material would have to be gathered and the cable manufactured on the Moon.

Several years later, Arthur C. Clarke popularised the idea in his novel "Fountains of Paradise", published in 1979. The concept of the Space Elevator proposed by Clarke is to construct a rigid connection between a point in geostationary orbit and a planetary surface. The fundamental problem of the last decades has been that no material known to man would be able to withstand the mechanical tensile forces, which would tear the cable apart. Recent developments in the field of nanostructures with carbon molecules indicate that the required physical properties are now within our grasp, thus having the potential for drastically lowering the cost of access to space. The transportation system would consist of a series of "cable cars" moving along the space elevator and then being released into geostationary orbit.

A potential construction strategy could be to move a carbonaceous chondrite asteroid into a stable orbit around our planet. Automatic machines would then process the materials at their source and start producing a cable like a spider. Years later, the cable would reach the ground and the connection between the planetary surface and geostationary orbit would be established. Problems - besides the cost, the difficulty of moving an asteroid (even one just a few kilometres in diameter) and the lack of automatic machines - include dynamical friction when the cable interacts with the uppermost winds in the Earth's atmosphere, and the periodic gravitational pull of the Moon.

There are a variety of difficulties with the proposal to stretch a rope from the Earth to orbit, which are not solved solely by carbon nanotubes. These materials are very strong and light, but have not yet been incorporated into working plastics with high strengths. One would be concerned that such a plastic (like Kevlar) would be strong only in one direction and therefore might not be as strong as one might expect when made into a rope. A second challenge would be the celestial-mechanics difficulties with Clarke's idea, given that such a construction would be affected by both the Moon and Sun and their tides.

NASA has recently completed a detailed study of the space-elevator concept and concluded that in possibly 50 years or so, this cheap method of transportation to geostationary orbit could become a reality and dramatically lower the cost of getting into space.

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