Step aside, space elevator evangelists – here’s an idea for joining the earth’s surface to space that’s much simpler, cheaper and safer than a big ribbon of carbon nanotubes.
A team of Canadian researchers have proposed a hollow tower constructed from the inflatable tubular modules that are used in some modern spacecraft, which – if built on top of a suitable mountain – could reach 20 kilometers above the Earth’s surface and act as a staging point for space launches… or a tourist destination with much lower risks and costs than suborbital rockets.
The team envisages assembling the structure from a series of modules constructed from Kevlar-polyethylene composite tubes made rigid by inflating them with a lightweight gas such as helium. To test the idea, they built a 7-metre scale model made up of six modules (see image). Each module was built out of three laminated polyethylene tubes 8 centimetres in diameter, mounted around circular spacers and inflated with air.
To stay upright and withstand winds, full-scale structures would require gyroscopes and active stabilisation systems in each module. The team modelled a 15-kilometre tower made up of 100 modules, each one 150 metres tall and 230 metres in diameter, built from inflatable tubes 2 metres across. Quine estimates it would weigh about 800,000 tonnes when pressurised – around twice the weight of the world’s largest supertanker.
Of course, the caveat is that this is just a theory at the moment – but it at least has the merits of being based entirely on existing technology. It seems that inflating things to reach space is quite the fashion at the moment…