Forget rockets and space planes. In future we might be taking an elevator into space.
The Japan Space Elevator Association is planning to build an elevator that will take humans and cargo into space.
It will use a cable attached to the Earth’s equator at one end, and a satellite at the other. Attached to it will be carriages that travel up and down.
It sounds simple, but there are lots of challenges.
To make sure the satellite stays above the same spot on the ground it must orbit once every 24 hours, in an orbit 36,000 kilometres above the Earth. A second cable must be attached in the opposite direction, to keep the elevator balanced. This means the cable will be 72,000 kilometres long.
The cable must also be very strong. It has to cope with wind and lightning in the Earth’s atmosphere, and colliding meteors and space junk in space.
Therefore engineers will use tiny tubes of carbon, called nanotubes, that will be more than 180 times stronger than steel.
The association believes the space elevator will cost $10 billion and take more than 10 years to build.
This might sound expensive, but it will be much cheaper to use than a rocket or the space shuttle, which can cost up to $400 million per flight.