How a Japanese Scientist’s Discovery Could Lead to Space Elevators – Carbon Nanotubes

The year is 1991, in Japanese physicist Sumio Ijima’s lab. Taking two graphite electrodes, Ijima applies an electric current, sparking a cloud of carbon gas, vaporizing the tip of the anode. As the gas clears, Ijima sees a layer of black soot, which contains the world’s first carbon nanotube. This microscopic material has the potential to revolutionize the way engineers go about design for decades to come. What started out as an encouraging experiment could result in the development of technologies that have not left the realm of the sci-fi world, most notably of all, the space elevator.
Carbon nanotubes are essentially hollow tubes composed of Carbon atoms, arranged in a hexagonal lattice. The individual carbon atoms are connected via covalent sigma bonds between the hybridized orbitals of multiple carbon atoms. Hybridization is a fusion of existing orbitals (regions where electrons exist), often done by elements such as carbon. This unique hybridized structure is responsible for many of the appealing material properties that carbon nanotubes offer. They are lightweight, electrically conductive, and biocompatible. This means they could be used to create hyper efficient computers, medical devices, and even prosthetic muscles. However, there is one possibility that easily captures the attention and imagination of humanity’s explorative tendencies. Carbon nanotubes have the highest tensile strength of any material known to mankind. This, combined with its low weight, gives it an incredibly high specific strength (strength to density ratio), making it a perfect candidate for the most ambitious of humanity’s projects, most notably, the space elevator. It is often conceived as a cable reaching from the earth’s equator into space, used to transport resources and spacecraft higher up, so it is easier to launch. Such a cable demands strong and lightweight materials in order to remain structurally sound, considering the harsh conditions in space.
While carbon nanotubes are made up of one of the most common elements, seen in the world all around us, they are not particularly easy to produce. As it turns out, making a long tube out of a material that is a molecule thick is extremely difficult. This raises costs, and reduces feasibility. So, in a world where funding and desire were to be available, we still would not be able to construct a space elevator. However, this doesn’t mean that we won’t be able to in the future. Research and development in this field is focused on optimizing the process of material production so that we can feasibly and cost-efficiently obtain as many carbon nanotubes as would be necessary to build a massive space elevator reaching kilometers into the skies and beyond. Further R&D is going into optimizing the carbon nanotubes, as current tensile strength hovers around 63 GPa, but the theoretical limit is around 300 GPa.
Overall, carbon nanotubes are an incredibly promising material – not only for feeding our imaginations in building space elevators, while also having the potential to furthering the fields of medicine, computer engineering, and more! And it all started in Sumio Ijima’s lab in 1991.


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