Space Elevator – Science Fiction or the Future of Mankind?

Adventurous idea with tradition

The idea of ascending into space by lift, a tower or over a kind of bridge is not new. As early as 1895 the Russian rocket pioneer Konstantin Tsiolkovsky, inspired by the Eiffel Tower in Paris, thought about a tower into space.

In 1960, the Russian engineer Yuri Artsutanov first formulated the idea of placing an Earth companion in geostationary orbit in the newspaper "Pravda". There - at an altitude of 36,000 kilometres above the equatorial plane - the satellite would orbit the Earth at the same time as the Earth rotates around its own axis. As a result, the satellite would appear to stand still above a certain point on the Earth. Now a rope is stretched between the two points and you could easily ascend into space by lift.

The concept of the space lift finally gained wider popularity in 1979 with a novel by science fiction star author Arthur C. Clarke. In his "Fountains of Paradise" (published in Germany in 1979 under the title "Lift to the Stars") Clarke describes a world in which astronauts and payloads are transported into space by lift.

And in the famous Mars trilogy by science fiction author Kim Stanley Robinson, the Mars colonists travel down to the Red Planet in a space elevator.

Space elevators - the principle

But the space elevator is not only a science fiction topic. Since the nineties, researchers have been working on the realisation of the concept.

The essential component of any space lift would be an unimaginably long cable or ribbon, which would extend from its anchorage on the earth's surface into space. The cable would have to be around 100,000 kilometres long so that the centre of gravity of the construction is above the geostationary orbit, so that the centrifugal force has a stronger effect than the force of gravity.

The cable could be considerably shorter if a space station or - as in Robinson's Mars story - a captured asteroid were attached to it as a "counterweight" in space. The cable, anchored on a platform on the Earth's equator, would thus tension itself. Gondolas could ascend from it and transport people and other payloads into orbit. A laser on the Earth's surface could supply the gondolas, also known as "climbers", with the energy they need for the ascent via photovoltaic cells on their underside.

Achilles' heel - cable material

However, the concept of the space elevator stands and falls with the development of a super-strong cable. The elevator cable, several 10,000 kilometers long, would have to be made of an extremely tear-resistant material. A steel cable, for example, would tear at a length of only 9 kilometers under its own weight.

The American scientist Bradley Edwards is using a new super-stable material here, the so-called carbon nanotubes (CNT). CNTs are super-thin, atomic-thick graphite foils that are rolled into a tube. According to Edwards, the tensile strength of these novel carbon fibers exceeds that of steel by a factor of one hundred.

For several years, Edwards has been developing a space lift and its components together with the US companies Highlift Systems and LiftPort. If Edwards is to be believed, it will only be a few more years before the nanotubes can be processed into a virtually indestructible cable material made of carbon fibers.

Quantum leap for space travel

Optimists like NASA consultant Bradley Edwards are certain that the space elevator will be in operation before 2050. "In as little as 15 years, we will be able to send astronauts into space at the push of a button," says Edwards. A space elevator would change the face of space travel dramatically. Payloads could be put into orbit at one hundredth of the current cost, which ranges from 14,000 to 32,000 euros/kg. Many nations that have no chance today would have access to space. Large space stations and orbital hotel complexes would be built, combined with a flourishing of space pleasure tourism. And presumably, interplanetary space probes and ships would then be assembled in orbit, which could then be launched - untroubled by the Earth's gravity - to the planets, moons, asteroids and comets of our solar system.