When I was a little kid long ago, I read a comic book where a man in a spacesuit climbed a ladder all the way to space. It turns out that an elevator to space was first written of in 1895 by the Russian scientist, Konstantin Tsiolkovsky. In 1979 two different novels were published by well-known science fiction authors that featured the construction of the first space elevator. The novels shared some similarities but were just a case of an idea whose time had come.
The basic idea of a space elevator is to have a tower that reaches all the way from some spot on the equator to some sort of massive anchor like an asteroid in geosynchronous orbit and beyond. This would make moving materials and people up to orbit and down to Earth much, much cheaper than the current system of launching such payloads by chemical rockets as is currently the practice. There are many technical problems that would have to be overcome before such a space elevator would even be theoretically possible.
As the private space industry ramped up in the past couple of decades, there was a surge of interest in what were called tethers. These would be strong cables that could be used for many purposes in space and also serve as possible path forward toward space elevators. Tethers could be used to deorbit satellites when they reached the end of their life. Long strong tethers could rotate above the surface of the Earth and be used to raise and lower cargo to and from orbit. There were even designs for tethers that could be used to raise a spacecraft from Earth orbit to escape velocity for missions in deep space. Tethers Unlimited is a space industry startup that was founded in 1994 to explore tether technology. Unfortunately, interest in tethers waned and TU has had to develop and sell other space technology in order to survive.
One of the first things needed for an actual space elevator would be an incredibly strong material that would be able to handle the enormous stresses that would have to be endured by such a structure. The discovery and development of carbon nanotubes may be the basis of materials strong enough to create space elevators.
Another problem that has to be addressed is the problem of moving an asteroid into geosynchronous orbit to serve as an anchor. A space industry startup called Made in Space has sent a 3D printer to the International Space Station for testing. This company has published plans for sending a probe with a 3D printer to rendezvous with an asteroid. Once there, the plan is for the probe to deploy the printer and use asteroid materials to build a mass driver and a navigation system that would permit the asteroid to fly itself to a convenient location such as a Lagrange point in the Earth-Moon system or a geosynchronous orbit above the Earth.
Now that some realistic technologies are being develop that could lead to a space elevator, space industry companies and universities in Japan have committed to developing a space elevator. Some of these efforts will be explored in my next post.