^ Yeah, I think we might be talking about two slightly different things. Special relativity is usually concerned with two people in constant relative motion, where all observers think everybody else's clock is slow (and you also get into Lorentz contraction and other effects), but other odd things show up when the relative motion is altered to form a closed path
, but closing the path required applied forces to alter the motion.
I'm not sure if this new drive would involved just normal doppler effects or what are termed relativistic
doppler effects, and how the idea of a non-accelerating reference frame that accelerates (space-time contracting in front, expanding in back) alters the situation. I'm sure the original articles on the earlier conception of this drive system should cover it in some detail, or at least the discussions about the earlier (high-power requirement) drive system.
Sounds like we might have to do lots of digging to get our mental models straightened out.