Is a ribbon made out of carbon nanotubes the key to building a cheaper, safer pathway to space?

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Getting into space is hard, not to mention expensive. Only a few people go every year. What if, instead of rocket propulsion, you could just hop on a space elevator?

It sounds far fetched but for 10 years now the International Space Elevator Consortium (ISEC) has been meeting annually, searching for innovations that will lead to the big, elusive space-elevator breakthrough. The next ISEC conference begins in Seattle later this month.

BBC Future's Richard Hollingham explains the design of a theoretical space elevator. He writes:

These futuristic engineering feats consist of a cable - also known as a ribbon or tether - of material stretching from the Earth's surface into orbit. An anchor and Earth's gravity at the lower end, and a counterweight and centrifugal force at the top end keep the elevator's "cable" taut and stationary over ground station. Robotic 'climbers' would then pull themselves up the ribbon from the surface, through the stratosphere and out into space, potentially powered by lasers.

The trick is the material, which, Hollingham says, would have to be "light, strong, flexible ... oh, and stretch, without breaking, for some 100,000 km (62,000 miles) -- higher than geostationary orbit." Carbon nanotubes -- cylinders of aligned carbon atom -- may make that possible. David Horn of ISEC tells Hollingham, "Carbon nanotubes can be spun into cables and tethers, just like rope is made ... theoretically they would be strong enough. We just need to figure out how to manufacture the ribbon out of these materials in large quantities." 

Horn, Hollingham reports, remains hopeful that such an engineering feat is possible. "Space elevators are possible," Hollingham concludes. "Eventually, I would suggest, they are also inevitable.