OT: About Space Elevators

[geoschmo]

The purpose of the ground link isn't to keep the ribbon taut. The ribbon doesn't have to be rigid, just basically stationary. You can't let it move around too much or you get problems with harmonic vibrations on the line. That would cause wild gyrations in certain spots that could damage the cable and/or cause the climbers problems. Anyone see the video of "Galloping Girdy", the bridge that tore itself apart in the wind. That wasn't because of a tremendous wind, it was just a slightly more windy than normal day, but the frequency of the vibrations in the bridge tore itself apart. That's the concern with the wind for the space elevator. That sort of thing can be actively dampened for the ribbon, but that requires manipulation at the ends. So they have to be attached to base stations. That is the danger of wind.

I don't know if they have any plans to reel up the cable in emergency situations like this, but there is no reason why you couldn't do it all the way from the high orbit. An intermediary station would be an unnceccesary complication. You don't have to take up the entire length of the ribbon, jsut reel up 15 miles or whatever to get the bottom end above the weather. The only quetions would be the reel having sufficent torque to take up the mass of the entire length of the cable. But the reel will have to be able to handle the mass of the entire length of the cable anyway or you would never be able to get it down to the ground in the first place. The only way to set the elevator up is to launch the spool in the conventional way and then reel it down from orbit.

Geoschmo