Very interesting, but why won't it ever leave the atmosphere or at least rise far enough that it could reach the Kármán Line (~100km). The record according to jgc is ~40km. Why is it so difficult to go from 40km to 100km if these zero-pressure valves exist?

(PS: I am aware the Kármán line actually has to do with aerodynamic lift (and therefore may not really be applicable to lighter than aircraft). It just chose it because it's the commonly accepted "edge of space")