Upon considering the possibilities for a single permanent platform for the VBP, I suspect it's not going to be possible at first, at least not in the way that, say, the Empire State Building is permanent. I believe that the use of the elevator and other maintenance techniques you have suggested will allow us to extend the time we can keep a platform deployed to six months or more, and I know we can get the two month minimum out of it that is necessary to put it up safely in the first place. It's remotely possible that we might even get a few years of wear out of it if we're lucky. But eventually it must come down.

The reason is simple: Eventually, something is going to wear out on the platform that we simply cannot lift on the elevator. There are going to be components of the VBP platform, like the tether, that will require a second VBP platform just to raise up to the target altitude.

With a second VBP platform -- this one without any payload except the tether -- we can raise the replacement tether from the same ground station to the altitude of the first platform without having to reel it back in. Mooring the two together at altitude, the tether attached to each will take up its share of the load due to wind drag, so that we will not have to deal with doubling the load on a single tether. Given a highly modular design, it would require less applied force to transfer individual components from one platform to the other than it would to transfer and secure a fully deployed tether, and the tethers cannot be swapped without removing support from one platform or the other. Then the used tether and stripped platform are cut free in separate pieces. The old platform is brought down by remote control, and the discarded tether is brought down by a combination of balloon and parachute. The new platform then continues the mission.

Now, at intermediate altitudes, even using the old tether as a guide on its way up, winds blowing at different directions will try to twine the new tether around the old one. By the time the new platform reaches the top, line tension alone will be enough to unwind some of this, but not all. This twining will not impede the fall of the old tether once it's dropped, but could allow the falling tether to rub against the new one on its way and/or foul the recovery chutes. This can be partly solved by unwinding the platforms from each other before mooring them together. (Or we could spin the ground station instead.) So long as it is allowed to fall rapidly enough, the intermediate winds will tend to carry a falling tether away from a taut one on its descent.

The beauty of the scenario is that while the total force on all of the tethers is huge, the share of this force on each individual tether can be quite reasonable, regardless of how many there are. Wind forces are relatively uniform over short horizontal distances, so each platform is subject to pretty much the same wind, allowing them to move in unison. In fact, with more tethers you can secure the platforms together at altitude to improve stability and strength. Though we've shied away from additions such as guy lines because they add unnecessary extra weight to a single platform, a multiple platform design should be able to support them just fine. This would improve stability even more. If we raise the whole thing as a single structure, select sections could far exceed the 80T or so maximum payload per platform that is the most we could hope for with a single tether, because the rest of the structure would take up the extra load. The whole composite structure could make the treacherous ascent as one group, with the platforms lined up behind each other like racers tailing each other to take advantage of the leader's wake.

As long as we would be sending up a structure with multiple platforms, we might as well dream up things to put on them. We could have entire platforms devoted to living quarters, commercial facilities, support structures, and (dare I type it? :) ) industrial services & processing. The whole complex could be linked together by a series of pressurized tube "rope bridges." And the best thing is, it could be expanded by simply sending up new platforms. If we can give sufficient incentive to make people want to work there and make it desirable for them to live there at the same time, we could find this forest of VBP platforms making the transition from "outpost" to "settlement" to "small town."

In the interim, an airship ferry like those being developed by Lindstrand, Lockheed and other companies could solve a great deal of the mass vs. maintenance problem for a single platform. Provided it were capable of rondevous (a bit iffy given our conditions of high winds and thin air), an airship could deliver payloads the size of our entire platform, enabling us to change out payloads (or platforms) without descending. An airship ferry could deliver large rockets for orbital launch, or a new supply of lift cells and hydrogen. Because it would not itself be attached to another tether, it would have some flexibility in being able to provide extra lift to the platform. Unfortunately, it would also increase the drag on the platform dramatically if it docked anywhere except in the lee (where it can't provide much extra lift).