"But the airport officials were scared. They didn't know whether the destruction of the launch loop was an isolated incident of terrorist sabotage, or maybe the beginnings of a revolution-no one seemed to think, ever, that it might have been just a simple accident. It was scary, all right. There's a hell of a lot of kinetic energy stored in a Lofstrom loop, over twenty kilometers of iron ribbon, weighing about five thousand tons, moving at twelve kilometers a second. Out of curiosity I asked Albert later and he reported that it took 3.6 x lO^8 Joules to pump it up. And when one collapses, all those Joules come out at once, one way or another."

From Heechee Rendezvous:

http://www.amazon.com/Heechee-Rendezvous-Frederik-Pohl/dp/03...