Today is the day. You and your research team are finally going into space to test your new devices. Each of you hugs your family goodbye as you prepare to start your journey. Instead of walking up to a spaceship, you walk up to what looks like an ordinary platform with a small chamber, just big enough to fit you and your three team members. Going through the chamber and straight up into the sky is a very fine cable. You follow this cable with your eyes as far as you can see; it goes straight up into the clouds and disappears out of sight. Your teammates have already piled into the chamber. You take one last look at earth then get in and lock the chamber door. With a sudden jolt, the chamber starts quickly rising. Next stop – Space Station!
Right now this space elevator scene is science fiction but many people hope it will be a cheaper, faster way to transport people and materials into space someday. Scientists have raised a number of issues that would have to be overcome before the space elevator idea could become reality.
Artist depictions of space elevators. (1) (2)
One main obstacle to making a space elevator is finding a material for the cable that is strong enough to withstand a huge amount of tension. Some scientists think that cables made from carbon nanotubes could be the answer. Nanotubes are very light weight and very strong, which is exactly what would be needed in a space elevator cable. However, the strength measurements on carbon nanotubes are based on tubes that are only millimeters long. As nanotubes grow longer, they are more likely to have defects (small imperfections in the structure) which make them weaker. Before the space elevator becomes possible, scientists will either need to find ways to make very long defect-free nanotubes or find other light-weight and super-strong materials to make cables from.
A nanotube defect. (3)
- Image by Pat Rawling
- Image from American Scientist
- Image from http://theor.jinr.ru/
Wikipedia’s Space Elevator entry