Guest essay by Eric Worrall
South China Morning Post has published a claim that Chinese researchers have successfully synthesised a sample of a carbon nanotube material so strong it could be used to construct the tether cable of a space elevator.
China has strongest fibre that can haul 160 elephants – and a space elevator?
Scientists say just 1 cubic centimetre of the carbon nanotube material won’t break under the weight of more than 800 tonnes
Tsinghua University researchers are trying to get the fibre into mass production for use in military or other areas
PUBLISHED : Friday, 26 October, 2018, 12:03am
A research team from Tsinghua University in Beijing has developed a fibre they say is so strong it could even be used to build an elevator to space.
They say just 1 cubic centimetre of the fibre – made from carbon nanotube – would not break under the weight of 160 elephants, or more than 800 tonnes. And that tiny piece of cable would weigh just 1.6 grams.
“This is a breakthrough,” said Wang Changqing, a scientist at a key space elevator research centre at Northwestern Polytechnical University in Xian who was not involved in the Tsinghua study.
The Chinese team has developed a new “ultralong” fibre from carbon nanotube that they say is stronger than anything seen before, patenting the technology and publishing part of their research in the journal Nature Nanotechnology earlier this year.
“It is evident that the tensile strength of carbon nanotube bundles is at least 9 to 45 times that of other materials,” the team said in the paper.
They said the material would be “in great demand in many high-end fields such as sports equipment, ballistic armour, aeronautics, astronautics and even space elevators”.
Those cables would need to have tensile strength – to withstand stretching – of no less than 7 gigapascals, according to Nasa. In fact, the US space agency launched a global competition in 2005 to develop such a material, with a US$2 million prize attached. No one claimed the prize.
Now, the Tsinghua team, led by Wei Fei, a professor with the Department of Chemical Engineering, says their latest carbon nanotube fibre has tensile strength of 80 gigapascals.
If this claim is verified by other researchers, the properties of this new material are straight out of science fiction.
Space elevators are the ultimate cheap space launch technology. Instead of blasting into space using a rocket, space elevators allow launch vehicles to literally climb to orbit along a long cable, using electric power supplied via the cable.
The way space elevators work, a satellite is placed in a geosynchronous orbit, and a long cable is dangled down to Earth, where it is tethered to a ground station. Geosynchronous satellites orbit the Earth once every 24 hours, so from the point of view of someone on Earth they appear to permanently hang in the same place in the sky, providing the perfect orbital tether to the top of a very long elevator cable. TV satellites are also placed in geostationary orbits, so you can point your satellite dish at the transmitter, and never have to adjust it again.
The catch is the tether cable has to support its own weight for at least 22,000 miles, so the cable material must be immensely strong and extremely light. The new Chinese nanotube material may satisfy both of these requirements.
Space elevators could be used to construct solar power satellites for an affordable price.
The new material might even make electric cars practical – the Post claims it could potentially be used to construct a flywheel battery for an electric automobile capable of holding 10,000 miles worth of electric charge.