🛗 Space elevators

A space elevator is a cable from the equator to beyond geostationary orbit, kept tight by the planet's spin like a stone on a string. Climbers could ride it to space without rockets.

• The cable would need a material far stronger than steel — carbon nanotubes or graphene are the candidates.
• No one has built one; on the Moon, with weaker gravity, it would be much easier.