The weight of the pipe, even lightweight plastic, must be taken into account, as well as the tremendous friction with the walls of the pipe compared to the very small volume cross section of the pipe.
The pressures needed at the bottom of the pipe would be so huge that it would burst any pipe light enough to be lifted aloft, or the pipe would be so heavy to withstand the pressure that it couldn't be lifted.
Another perfect plan on paper.
20 km is approximately 65,000 feet. Three times worse than I originally thought...
Shortly after 9/11, I wondered if a big-lift, stabilized helicopter, with a water nozzle mounted underneath, could lift a length of water hose, with the water being pumped by fire engines below.
A bit of back-of-the-napkin math showed that you'd reach the bursting point of standard fire hose long before the water you were pumping reached the floors where the fires were burning in the WTC.
Ohho, the pipe gets thinner the higher it gets till
eventually it’s not there at all, that’s where the
water comes out.
Also they can pump hydrogen into the water and let
it counter balance the weight.
See how simple it all is..../s
Seems like it would be easier to just let the pipe down
from the ISS...../s