On Thursday, June 11, 2020 at 1:24:46 PM UTC-4, David Spain wrote:

Another feature not to be discounted are stops along the cable that
remain in the atmosphere. You could have observation stations in both
lower and upper troposphere, stratosphere and ionosphere. Something that
is exceedingly difficult to do today, even with balloons.

Something that I haven't heard addressed, is how to protect the cable from
aircraft collisions. No matter how well marked and lighted, sooner or later an
aircraft will hit it, resulting in the severing of the cable and the crashing of
the aircraft.