Carbon nanotubes are not even close to strong enough to build a space elevator, that's the whole problem. We have no idea if anything that strong even exists, at this point.
http://images.spaceref.com/docs/spaceelevator/521Edwards.pdf
The study also addresses lots of other engineering issues. This work sparked a lot of subsequent R&D that is still ongoing. We're not yet able to actually make the ribbon described in the study, but we're getting there.
Then again, if you're willing to rely on dynamic support, a minimal orbital ring could be built with materials we have today:
> The material required for construction of the cable is a carbon nanotube composite: currently under development and will be available in 2 years.
Its actually crazy that the report thinks that we would have the necessary material in 2005 and is still used as evidence of a practical space elevator. The graph on page 10 shows the absolutely massive extrapolation from data at the time. It seems disingenuous to even talk final price and time to construct a space elevator (as is done in the one-page brief) without any data confirming the possibility of manufacturing the goal material.
Do you have any sources for that? Because from a quick search online I’m seeing that SE requires a tensile strength of 60-80 GPa and the theoretical max strength of carbon nanotubes can reach 150-200 GPa (with a 63 GPa being demonstrated back in 2000)
We can imagine a molecular machine that would grow carbon nanotubes like a silkworm grows silk filaments, but we are many decades away from this kind of things.
Moreover, the tensile strength is not all. It must resist to some intentional or accidental collisions, to earthquake waves and so on.
http://images.spaceref.com/docs/spaceelevator/521Edwards.pdf
It does not contain any experimental results supporting this hope, because only a strength similar to steel has been obtained.
Perhaps it will become possible to obtain a higher tensile strength than with other materials by this method, but it is likely that this will require longer nanotubes and perhaps some other kind of polymeric resin instead of epoxy. It is very difficult to find anything that has high enough adhesion to carbon.
A key part of the design is for the glue to have a low enough melting point, so if the cable breaks, it melts on reentry and you don't get lots of little fluttery bits instead of a big super-strong cable wrapping around the planet.