Update.
Simplified fixation of the Magnus balloon
The structure, including a central shell with ball bearings, can slow down the rotation of the Magnus balloon. So, a simplified fixation is studied. A mounting is planned, consisting of a rod passing through the center of the hub and including a bearing, according to a device like that of “Kiwee” [1 and 2]. A light (and possibly inflatable) wheel helps minimize potential contact with Magnus balloon.
Temporary conclusion
Both solutions may prove impractical.
