One of the more fantastic ideas for getting into space is the space elevator. The basic idea is that a super strong cable reaches from the Earth’s surface to a huge counterweight that is beyond the twenty-three thousand miles geosynchronous orbit. Vehicles like elevator cars would climb up and down the cable lowering the cost of sending things to and from orbit by several orders of magnitude.
The idea was first proposed in 1895 by Russian scientist Konstantin Tsiolkovsky. An old comic published in the U.S. in the 1950s depicted a man in a space suit climbing a ladder into space. American engineer Jerome Pearson published the first technical description of a space elevator in 1975. The concept of a space elevator came to popular media with two novels, both published in 1979. These novels were The Fountains of Paradise by Arthur C. Clark and The Web Between the Worlds by Charles Sheffield. Since then there have many mentions of space elevators in popular novels, comics, movies and television shows.
The main technical problems with constructing a space elevator are buckling, dynamic stability and strength. Engineers believe that a satellite in geosynchronous attached to the cable could solve the problems of buckling and dynamic stability. The unresolved problem with strength lies finding a material that has the incredible strength necessary to withstand the enormous strain that such a construct would endure. After a hundred and twenty-five years, it now appears that such a material may be available.
The cable for the space elevator would have to have a tensile strength of seven gigapascals. One pascal is defined as about one newton per square meter. One newton is defined as the amount of force necessary to accelerate one kilogram of material at the rate of one meter per second squared. Peason suggested that perfect crystals of graphite might have the strength necessary.
Chinese scientists at Tsinghua University have announced the development and patent of a carbon nanotube fiber with a tensile strength of eighty gigapascals. This is over ten times stronger than theoretical studies say is needed to build a space elevator. Part of their research has been published in the journal Nature Nanotechnology. The Chinese scientists said, “in great demand in many high-end fields such as sports equipment, ballistic armor, aeronautics, astronautics and even space elevators”.
Nicola Pugno is a professor of solid and structural mechanics at the University of Trento in Italy. He thinks that the new fiber developed by the Chinese scientists is promising. He said, “Having a strong mega-cable and maintaining its strength and flaw tolerance is the biggest challenge. The Nature Nano report [from the Tsinghua team] is a key step towards the solution … thus, never say never.”
One concern that I have about the creation of a space elevator is that it would be very vulnerable. If the base was destroyed, the counterweight would yank the cable into space. This would wreak havoc with the satellite to which the cable was attached. A missile or a bomb in one of the elevator cars could break the cable above the surface of the Earth. Any length of cable that was below the cut would fall back to Earth, wrapping itself around the equator causing devastation and tsunamis. If the break was above the satellite in geosynchronous orbit, the satellite would be yanked down to Earth. There would be enough cable to wrap almost all the way around the Earth. As useful as a space elevator might be, I am afraid that it would be much too dangerous to ever be constructed.