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China Produces Nano Fibre That Can Lift 160 Elephants - and a Space Elevator? (nzherald.co.nz)
Slashdot reader hackingbear quotes the NZ Herald: 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 centimeter 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... 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...
The space elevator idea has remained in the realm of sci-fi, physical and mathematical models because there has been no material strong enough to make the super-light, ultra-strong cables needed... 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 [over ten times more than the 7 gigapascals strenth NASA estimated to be required for a space elevator]... Chinese and Russian space scientists, for instance, are working together to find a safe, effective way to lower a fine, feather-light cable from a high-altitude orbit to the ground.
Wei also said his team was trying to get the carbon nanotube fibre into mass production for use in defense -- or to create super fast flywheels in a mechanical battery, which would have 40 times the energy density of a lithium battery.
The space elevator idea has remained in the realm of sci-fi, physical and mathematical models because there has been no material strong enough to make the super-light, ultra-strong cables needed... 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 [over ten times more than the 7 gigapascals strenth NASA estimated to be required for a space elevator]... Chinese and Russian space scientists, for instance, are working together to find a safe, effective way to lower a fine, feather-light cable from a high-altitude orbit to the ground.
Wei also said his team was trying to get the carbon nanotube fibre into mass production for use in defense -- or to create super fast flywheels in a mechanical battery, which would have 40 times the energy density of a lithium battery.
Asian or African elephants, laden or unladen?
African elephants, unladen.
TFA says 160 elephants, or 800 tonnes, or 5000 kg per elephant. That is about the average weight of an African elephant. Females are about 4000 kg and males about 6000 kg, averaging to 5000 kg.
Asian elephants are considerably smaller, averaging about 4000 kg. The only way to average 5000 kg with Asian elephants would be to use all males, but the males tend to be aggressive and difficult to handle, and there is no way you are going to get 160 of them onto a scale.
That even when the tech is ready:
"The Space Elevator will be built about 50 years after everyone stops laughing." - Arthur C. Clarke
Quoting volume for a rope is not very helpful.
Indeed. That is one of the stupidest metrics I have seen in a while.
The cross sectional area would be much more interesting for saying how much it can carry.
Well, they do say 80 gigapascals, which means 80 billion newtons per square meter. That is 8 million newtons per square cm, which in earth's gravity is equivalent to supporting ~800,000 kg, or 800 metric tonnes. Which is roughly the weight of 160 elephants.
For a space elevator, an important metric is how much of its own length it can support. Carbon nanotubes have a density of about 2.5 gm/cc. So 800 tonnes is about 3200 km of fiber with a square cm cross section. TFA says that is enough, but that will get you only a tenth of the way to GEO.
Let's not forget that carbon nanotubes make asbestos look like cotton candy, healthwise. In animal studies, exposure to CNTs induced sustained inflammation, fibrosis, lung cancer following long-term inhalation, and gene damage in the lung.
When all you have is a hammer, every problem starts to look like a thumb.