On Sun, Feb 25, 2018 at 11:16 PM, Tim <xxxxxx@little-possums.net> wrote:

I'm not sure what you mean by the "straight and level stretch of
track". This is all happening high in the atmosphere, probably at
least 50 km from the ground and more likely 100-150 km.

Sorry. I was assuming somewhat higher-tech materials, which could allow the end of the tether to reach ground level.

The points where it dips into the atmosphere will be
spaced out depending upon the period of rotation vs orbital speed, and
will also vary somewhat over time. A track doesn't really help
anything that I can see. Being in the right place at the right time
will require precise planning.

Even for the slower tether rotations where the tip never gets slower
than 4 km/s or so relative to ground, its height above ground will
still vary a lot even during its lowest second.

Why so? The hub of the system is capable of maneuvering, even in the real-world examples given. It's usually using (fuel-free) electromagnetic thrust, but in a near-future setting with working fusion generators it shouldn't be limited to this. So the hub should be able to reposition itself fairly precisely, well before it comes around to above the pick-up track again.

Richard Aiken

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