Space Elevator

A space elevator is a proposed type of planet-to-space transportation system. The main component would be a cable (also called a tether) anchored to the surface and extending into space. The design would permit vehicles to travel 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 geostationary orbit (35,786 km altitude).

The competing forces of gravity, which is stronger at the lower end of the cable, and the outward/upward centrifugal force, which is stronger at the upper end, would result in the cable being held up and kept stationary over a single position on Earth. With the tether deployed, climbers could repeatedly climb the tether to space by mechanical means, releasing their cargo to orbit. Climbers could also descend the tether to return cargo to the surface from orbit.

While this concept is not recent , but over a century old, it remained at theoretical level with no experimental demonstration of its validity since we need materials with the right strenght requirements for the tether component. With the discovery of graphene nanotubes, the space elevator concept became more feasible since they would have enough strenght to be utilized for the tether component.

Several competitions to promote space elevators were active during the 21st century to further promote the concept.