Low thrust to orbit for an airship has got to be bogus
This concept has a very fishing smell. Ion propulsion works fine in the vacuum of space where there is no drag force. However in the upper atmosphere there is still a drag force. With a blimp there would be a significant drag force even in the tenuous atmosphere of Low Earth Orbit. Drag scales with velocity squared times density times cross sectional area. Orbital velocity is around 7 km./sec. An ion propulsion system typically has the thrust of a grasshopper. I don't see an ion propulsion system over coming a blimp's atmospheric drag. Something is not right here.
Gary