I've never bought the idea of a 60,000-mile high "beanstock" anchored to the ground. Even if the tether were unreeled from geosynchronous orbit down toward the ground, there is a certain length beyond which it would snap under its own weight. That's why I went with the much shorter 3940-km rotating elevator, or "Rotavator". The hub taps the earth's magnetic field with nuclear electrodynamic engines for stationkeeping, while it swings a tether around once-per-hour, the tip just entering the upper atmosphere where a modified C17 Globemaster cargo aircraft can attach a 50-tonne payload. There may be some problems with buckling of the tether as it enters and drags the atmosphere. The lower 100-km of tether might not remain perfectly straight, and so the rendezvous might be a bit higher in altitude, but I think this is easily managed by using a longer tether. A longer tether (and a higher hub orbit altitude) means that the tether would dip into the atmosphere with less transverse velocity, which means less drag, which means less buckling, which means a lower rendezvous altitude is possible. Likewise it would rise almost straight up into space again with little transverse velocity. This is probably the most profound fact that I learned while running simulations with my computer program (which is available on my website). Very interesting.

I like the idea of an elevator that climbs the tether by squeezing it between two powered "rolling pins". That might make for a decent maintenance bot. However for my idea I think the tether will have to be reeled in regularly for maintenance, like a fisherman reels in his nets.