space elevator
Overview
A space elevator is any kind of solid physical connection between a satellite in planetary orbit and the planet's surface.
In practical application, space elevators are typically designed to be capable of lifting heavy loads between orbit and the surface of a planet, as this is the main economic justification for even considering such a difficult engineering task.
Space elevator designs currently focus on Earth-to-Earth orbit, as this is where transportation is currently most badly needed; in the more distant future, however, potential colonies on the Moon or Mars might also make use of a space elevator (and indeed these would be somewhat easier to construct, from an engineering standpoint).
Space elevators were envisioned for many years before any known material was strong enough to bear the needed loads; the discovery of Buckytubes has at last eliminated this major hurdle.
Types
There are two major types of space elevator:
- fixed cable: the cable stays still, and compartments on it using wheels or possibly some kind of magnetic traction
- moving cable: the cable moves continuously and compartments clamp on to it to move and let go when they reach a destination