I’ve heard there are materials that can withstand the image sort of the earth’s atmosphere, such as carbon nanotubes and Kevlar. Supposedly, a perfectly constructed bridge of such material could be used as a tether for a space elevator, although challenges exist in reliable construction.
To creatively navigate this issue, my protagonist is starting small – he wants to fly a balloon of such material filled with helium or some such floating gas up through the atmosphere, with a single thread of heat resistant material attached to it.
My questions are:
What material could such a balloon be made of that are light enough to float when filled with helium?
If helium wouldn’t work, is there another gas that would?
If such a balloon could feasibly be constructed, could it rise with a light-weight string of similar material attached? If one balloon is not sufficient, how about many?