Was thinking about taking down more of these high altitude balloons yesterday. If they contain helium then wouldn't some type of transmutation of the helium allow us to take them down slowly and keep them intact. We can do air to air refueling then why can't we rig a high altitude drone to do the same and "inject" the balloon with some type of liquid nitrogen thus freezing the helium and making it denser and heavier? The drone could be built in such a way that it could drop it fuel line and seal it's own part with a shutoff valve thereby sealing the dangling hose. Any thoughts?