Space is quite hard to get into - it’s actually not the distance that’s the problem; after all, our atmosphere is only 300 miles thick - actually, if you want to be realistic, the atmosphere is essentially 20 miles thick because 99 per cent of the gas is in this zone. Happily, thanks to gravity, our wafer thin layer of gas doesn’t just drift off into space.
Given that the essential height of the atmosphere is significantly less than the distance from Swindon to say… Oxford (although you could argue that the two are worlds apart…) you would think it would not pose that much of a challenge to get into space. Gravity is the problem - it takes a huge amount of energy to slip the surly bonds of Earth.
This is where the idea of a space elevator is so appealing. Inspired by the Eiffel Tower, Konstantin Tsiolkovsky came up with the concept in 1895. The idea has been a pipe dream of many scientists subsequently.
The space elevator consists of a huge cable anchored to the surface of the Earth and extending into space.
The pull of gravity on the upper end would (in theory) result in the cable being held up under tension and stationary over a single position.
The structure would then allow humans and hardware to be transported from the surface of the Earth to the atmosphere. So why hasn’t it yet been done? It’s all down to materials science - a 20-mile long cable capable of withstanding extraordinary pressures - it would need to be stronger and lighter than any commonly used material that we currently have.
However super strong materials are being developed that could hold the key to unlocking fast and simple access to the upper atmosphere - these include carbon nanotubes, boron nitride nanotubes and diamond nanothreads. In 1975, American scientist Jerome Pearson sketched out a concept, with a cable that was thickest at the orbiting end - where the tension is greatest - and thinner towards the surface of the Earth. But for his design to work, the counterweight would have to extend out to a mind boggling 89,000 miles.
With the development of carbon nanotubes in the 1990s, engineer David Smitherman realised that the high strength of these materials suddenly made the concept a possibility and put together a workshop at the Marshall Space Flight Center, inviting many scientists and engineers to discuss concepts and compile plans for an elevator to turn the concept into a reality.
And since then, a spate of serious proposals have been put forward - including one in 2014 by Google X’s Rapid Evaluation R&D team. The Google project concluded that no one had yet manufactured a perfectly formed carbon nanotube strand longer than a metre and put the idea on hold until further developments materials science was able to produce results.
The space elevator is closer than ever, as soon as all the elements are in place, the potential commercial gains are sure to kickstart development at a rate of knots. Watch this space.
