What types of atmospheric disruption (and other issues) would my skyhook make?

In this question:

Where to Anchor My Space Elevator

We get a new material:

Thanks to the recent discovery of handwavium filaments that can in principle be extruded to any length, we will be able to build space elevators sooner than most people would expect.

In my answer to that question, it becomes apparent that we'd prefer to go to orbit for free than use a space elevator. We'd use a rotating skyhook to do so.

From the wikipedia page:

A rotating tether is a type of cable that would orbit the Earth with a tip speed equal to its orbital speed (around 7-8 km/s). The tip would rotate down, moving in the direction of Earth's rotation. It would enter the atmosphere at low speed and pick up a payload from the ground or the atmosphere. It then carries it up into space.

However, a Boeing study in 2000 assessed that "Trying to lower the tether tip speed to 4.0 km/s (13 000 ft/s or Mach 13) would require a skyhook tether mass greater than 200 times the payload mass.

I'm unclear if 'low speed' means Mach 13 (when it hits the atmosphere) or not. In other literature (heh, wikipedia is literature), they extend the tether so that payload/attachment point comes sooner, and stays on the ground allowing time to process/move things into the container, lengthen the skyhook allowing more time on the ground, then a gentle lift away (although, looking at stuff some more, that example was on the Moon, with no air resistance at the surface).

But in any case, I suspect this will have some type of effect in/on the atmosphere/tether if it's anywhere above Mach 1.

Would a rotating skyhook hit the speed of sound in the upper atmosphere? Or worse yet, lower down in the thicker part of the atmosphere? How far do sonic booms propagate? What types of atmospheric disruption (and other issues) would my skyhook make? At Mach 13, I'd also expect a bunch of heating (How much? Enough to vaporize a nanotube?), as well as a trailing curve; which would reduce the time on the ground/at the attachment point.

posted almost 10 years ago

user3082‭

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