A normal traction elevator uses a cable to winch a cabin up and down between floors inside a building. There’s a counterweight on the other end of the cable to make moving the cabin easier. You step into the cabin, press a button and are winched to the desired floor by an electric motor. As you go up, the counterweight goes down and vice versa.
A space elevator, as you might imagine, takes this idea a bit further. It relies on a cable that runs from space to Earth – thousands of metres of cable. Instead of needing a rocket to go into space, you run a cabin up the cable, which uses a fraction of the energy of a rocket launch and causes no pollution.
Sounds impossible, but people have been giving this some serious thought over the years. Amazingly the idea has been discussed since 1895, when Russian rocket scientist and pioneer of astronautics, Konstantin Tsiolkovsky, suggested a sky ladder.
The first problem is figuring out what to attach the cable to in space. Satellites in geostationary orbit are the answer. Geostationary orbit is the special distance from Earth where objects stay in one precise spot overhead instead of orbiting around us. This would put our space anchor point at around 36,000km (22,200 miles) above the equator.
