Reply To: What is the current state of the project?

[emmetb]

Now imagine having to move the cable bottom to avoid each and every one of those little dots, simultaneously. And those dots are all moving! Clearly it’s an impossible task. But if you don’t do it, your cable takes impacts. So how long can the cable survive under such bombardment? Not long, is the guess here. And the problem is only going to get worse as time goes on and more and more junk ends up in orbit.

This really seems like a show-stopper for the pace elevator. Also its seems a practical space-elevator system needs some active daming to keep it from vibrating due to winds, tidal forces, etc. That all seems to make it highly impractical.

These guys have an interesting alternative concept:
http://www.tethers.com/LaunchAssist.html

How about changing their concept slighty: make the tether active at the top by employing a FF driven electric reel. This means you add additional lifting capacity by shortening the cable as the payload is ascending (a bit like an ice-dancer drawing the arms closer the the body to pick up angular velocity).Of course you can only draw the tether in slightly before reaching appex, but it still might have an effect. If it doesn’t then at least it is important to keep retracting the ribbon after launch in order to minimize the time of exposure of the tether to impact from space-debris.

In between launches, FF propulsion can be used to restore the orbit of the tether facility.