NASA is envisioning a 40,000km-high elevator extending into space. The Advanced Projects Office at Marshall Space Flight Centre has set a space elevator as a feasible goal using space tethers (strong light cables that have been used since the 1960s to couple a spacecraft together or transfer fuel between vehicles).

They want to build a 50km-high base tower with a cable tethered to the top reaching into space. The other end would be anchored to a counterbalance, perhaps a space station, or a cosmic hotel. One ambitious plan involves lassoing an asteroid to the other end of the cable to keep it stable!

Magnetic tracks would be laid up the side to grip floating space trams called ‘maglevs’ (short for ‘magnetically levitated’ vehicles). The cables would be constructed from tough new fibres called carbon nanotubes that are as strong as diamonds.

The initial idea came from Arthur Clarke, a sci-fi guru. He wrote a novel called ‘Fountains of Paradise’ describing a quest to construct a tower on a tropical island that reached up into the clouds and beyond.