Rick Sternbach wrote:
I don't have a copy of Franz Joseph's plans handy, but didn't he label them something like "space matter intakes"? This might have been his own take on what they could have been, and not something intended by Jefferies. More science fiction archeology.
FJ labeled the front end domes as "Space Energy/Matter Sink (Acquisition)" and the rear end domes as "Space Energy/Matter Source (Restoration)." IIRC, the idea was that all of the universe's "Energy/Matter" would be sucked into the engines on the front end and restored on the back end and that this process would have the effect of pulling the engines (and the starship attached to them) along at FTL speeds. It's not quite the same as Bussard's idea of collecting hydrogen as fuel (at least as I understand it...).
However, personally, I feel that the Sternbach/Okuda model of dome=Bussard collector and rear end=subspace field generator makes more sense and I happily retcon it over the TOS episodes. It doesn't really present any conflict to what was seen on-screen.
(Though I wonder why Cochrane's Phoenix
would have needed Bussard collectors when his ship was only meant to jump less than an AU in a test flight. Maybe that was just the maiden voyage... after all, what seems like it must have been a disposable launch stage was never dropped and presumably the whole thing wound up in the Air and Space Museum, so what do I know?)