The current issue of IEEE Spectrum features a cover story by former Los Alamos National Lab scientist Bradley Carl Edwards who is now leading an effort to build a space elevator. The idea is to suspend a 100,000 km cable, most likely made of carbon nanotubes, between Earth and geostationary orbit. An elevator could then be attached to the cable to shuttle materials, rockets, and people into space and back. (Previous posts about the space elevator here and here.) From Edwards's article:
Nuclear and electric rockets promise huge improvements in efficiency and will be vital to the future of solar system exploration, but they are impractical as a means of getting off Earth: they either don't produce enough thrust to overcome gravity or pose a potentially serious radiation hazard.
On the other hand, space elevators could haul tons of material into space all day, every day. And the core of the space elevator–the cable–could be constructed from cheap, plentiful materials that would last for decades.
A space elevator would be amazingly expensive or absurdly cheap–depending on how you look at it. It would cost about $6 billion in today's dollars just to complete the structure itself, according to my study. Costs associated with legal, regulatory, and political aspects could easily add another $4 billion, but these expenses are much harder to estimate.
Building such an enormous structure would probably require treaty-level negotiations with the international community, for example. A $10 billion price tag, however, isn't really extraordinary in the economics of space exploration.
