These plan to operate much higher at 60k feet and won't be tethered to the ground. The additional height will give them better coverage than the radar aerostats you mention. I think removing the tether might be required for them to be used a lot because the tether seems like it'd a) weigh a lot requiring much larger stats and b) if they're dense enough the tethers could pose a danger to air traffic (at the very least you'd have to route planes to avoid them). Both of those get worse as the stat operates higher and the forces on the cable get higher. It may become an issue where the increased strength required increases the cable weight beyond the point where an cabled aerostat becomes viable.
Comments
These plan to operate much higher at 60k feet and won't be tethered to the ground. The additional height will give them better coverage than the radar aerostats you mention. I think removing the tether might be required for them to be used a lot because the tether seems like it'd a) weigh a lot requiring much larger stats and b) if they're dense enough the tethers could pose a danger to air traffic (at the very least you'd have to route planes to avoid them). Both of those get worse as the stat operates higher and the forces on the cable get higher. It may become an issue where the increased strength required increases the cable weight beyond the point where an cabled aerostat becomes viable.