Only six? (Score 1)

I really don't see why it would be necessary to limit this thing to only six fans. If enough blades are used (per fan), they should be able to be made small enough to produce sufficient thrust. Granted, a dozen fans would tend to deplete the batteries faster than six would; but if power consumptionn is that big an issue, then why use six? Use four instead. Six fans tend to imply (at least to me) thinking in terms of up, down, forward, etc. In G, orientation as such ceases to exist as such. With four fans, the ball flys in its desired direction by first determineing it's desired direction, and then it calculates how much thrust is necessary by summing the vectors of the appropriate fans (technically, any number of fans would use the same method).

An easier method would be to use several dozen small, fixed compressed air jets. Only a few would be used at any one time, and things such as yaw, pitch, etc could be accomplished by jets set tangent to the sphere's surface.