
Up and down the 22,000 mile-long (36,000km) cables - or flat ribbons - will run the elevator carriages, themselves requiring huge breakthroughs in engineering to which the biggest Japanese companies and universities have turned their collective attention.
The biggest obstacle lies in the cables. To extend the elevator to a stationary satellite from the Earth's surface would require twice that length of cable to reach a counterweight, ensuring that the cable maintains its tension. The cable must be exceptionally light, staggeringly strong and able to withstand all projectiles thrown at it inside and outside the atmosphere. The answer, according to the groups working on designs, will lie in carbon nanotubes - microscopic particles that can be formed into fibres and whose mass production is now a focus of Japan's big textile companies... Equally, there is the issue of powering the carriages as they climb into space. "We are thinking of using the technology employed in our bullet trains," Professor [Yoshio] Aoki said. "Carbon nanotubes are good conductors of electricity, so we are thinking of having a second cable to provide power all along the route."







