It was Konstantin Tsiolkovsky, the Russian space pioneer, who first understood that multistage rockets could carry us into space. Years after his death, this insight brought him fame as the Father of space travel. Years later Yuri Artsutanov suggested that a shorter cable, rotating around its midpoint, might hurl objects into space like David releasing a stone with his sling. Now that we are accustomed to rockets, these concepts sound outlandish at best. Yet practical-minded engineers are starting to take a closer look at them.
Trouble is, rockets are expensive and wasteful.
The space shuttle is reusable, and so it cuts our equipment costs. Still, it uses up a lot of fuel. For really cheap space transportation, we'll have to do away with rockets entirely. The skyhook, or the rotating space elevator, could be what replaces them. Some 36,000 kilometers out, we have put dozens of satellites into so-called geosynchronous orbit.