Martin George discusses the mind-boggling technology involved and the dramatic possibilities of a space elevator.
At the end of September the Japan Aerospace Exploration Agency (JAXA) launched a rocket carrying a prototype that is testing a mind-boggling technology. It is called STARS-ME or “Space Tethered Autonomous Robotic Satellite – Mini elevator” and has the potential to raise us into the realm of science fiction.
The idea of a space elevator has been around for a while and was first introduced by Jerome Pearson at NASA in 1969. As it turns out, an engineer called Yuri Artsutanov had been working on the design for such a structure a few years prior, but because he never formally published his work, Pearson took most of the credit. The basic premise behind the idea sees a long, very strong tube anchored somewhere to the earth with a counterweight on the other end hundreds of thousands of kilometres in the atmosphere. Just as swinging a sock with a snooker ball inside maintains a straight line from your hand to the ball, so the cable would be kept taut by the counterweight moving due to the rotation of the earth. Some sort of device would be attached to the outside to transport people or cargo up the tube.
The recent experiment comprised of two satellites smaller than a football at different orbits with a 10m cable connecting them. A mock elevator would then run from the lower orbit to the higher orbit. Overall it was a success but the biggest limiting factor was not tested. Since the cable would need to run from the surface of the Earth to thousands of kilometres in the atmosphere, it would need to be lighter and stronger than anything in mass production today. As Graham Templeton from extremetech.com put it:
“Imagine a ribbon roughly one hundred million times as long as it is wide. If it were a meter [sic] long, it would be 10 nanometers wide, or just a few times thicker than a DNA double helix. Scaled up to the length of a football field, it would still be less than a micrometer across — smaller than a red blood cell. Would you trust your life to that thread?”
JAXA are not letting this phase them however and are endeavouring to stick to their plan of completing the Space Elevator by 2050: “current technology levels are not yet sufficient to realise the concept, but our plan is realistic.”
The “thread” material scientists are banking on at the moment are Carbon Nanotubes. This would give the elevator 100 times the tensile strength of steel for the same diameter. The interlocking carbon-to-carbon covalent bonds form one massive molecule that is very difficult to break.
Recent progress has been made with nanotubes. A team led by Professor Alan Windle at the University of Cambridge have managed to combine several nanotubes to make a weave.
Creating this weave on a large scale will be pivotal for using nanotubes in the real world: “The key thing is that the process essentially makes carbon into smoke, but because the smoke particles are long thin nanotubes, they entangle and hold hands,” Windle said. “We are actually making elastic smoke, which we can then wind up into a fiber.”
A big reason why innovators are so determined to progress with the design of a Space Elevator is because of the real world applications. On a small scale, the cost of Space travel would dramatically decrease. The cost per kilo to geostationary orbit would plummet from approximately £17,000 to close to £400. On the other end of the spectrum, the technology could be crucial to man’s first expedition to Mars.
The rocket could start at the top of the elevator and complete a couple of laps of the Earth before speeding off to the red planet. This method avoids the complications that make launching from the surface of the Earth so dangerous, and saves a substantial amount of fuel.
Space debris is becoming more and more of a problem by the day, with scientists predicting the density increasing to a point where a snowball effect of Satellites crashing into more Satellites could plunge us into the dark ages. Launching Satellites would be far less risky from space and clean up operations would be cheaper as well.
The recent breakthroughs are promising, and we have definitely come a long way since the technology was first dreamt up in the 1960s, however it’ll be a few decades before people are booking tickets for the Space Elevator instead of the London eye. This is definitely a piece of engineering that will one day benefit all of mankind and in a world becoming increasingly fragmented, it could be really exciting watching nations work together on this momentous project.