Space Elevator

Space elevator is one name for a tether connecting an orbiting body with the surface of a celestial body such as a planet.

Basic Tether
The simplest form of space elevator is a load-bearing cable attached at two ends.

Electrodynamic Tether
An electrodynamic tether uses the principle of induction to generate a difference in charge along the length of the tether as it cuts across a magnetic field.

History
Connecting a satellite to the Earth's surface was first proposed by Konstantin Tsiolkovsky in 1895, although he conceived the connection as a tower.

Because of the economic incentive, numerous groups and organizations supported the idea of a space elevator on Earth or the Moon, but no construction effort ever left the planning stage.

During the Respite
After the transfer of materials from the surface of the Moon began, the Bountiful Sky Project had plans to build a space elevator on the Moon. If completed, such a structure would likely have completely eliminated the need for the mass-driver at Shackleton and the ore tugs, simplifying the ore extraction and saving considerable cost.

After Arrival
It was known before the departure that the nuclear reactors, which had been intended for the Bountiful Sky Project and not for an expanding colony independent of Earth, had a limited life, and that extracting more thorium fuel would be difficult at best in the Saturn system. Electrodynamic tethers were proposed soon after Arrival to replace the reactors when their fuel was depleted.