A space elevator is a proposed type of space transportation system.
Its main component is a ribbon-like cable (also called a tether) anchored to the surface and extending into space. It is designed to permit vehicle transport along the cable from a planetary surface, such as the Earth's, directly into space or orbit, without the use of large rockets. An Earth-based space elevator would consist of a cable with one end attached to the surface near the equator and the other end in space beyond geosynchronous orbit (35,800 km altitude). The competing forces of gravity, which is stronger at the lower end, and the outward/upward centrifugal force, which is stronger at the upper end, would result in the cable being held up, under tension, and stationary over a single position on Earth. Once deployed, the tether would be ascended repeatedly by mechanical means to orbit, and descended to return to the surface from orbit.
ref: The International Space Elevator Consortium
ref: other dedicated website: www.spaceelevator.com
ref: 2012 Annual Space Elevator Conference Set for August 25-27