I did see something once on the science channel where a physics guru suggested the spacial problem may be overcome with a beacon of sorts. But then you could only travel to a time the beacon was active.
So how does that beacon (if physical) get placed in that time and space for them to do the computations from its feed back? Did he explain that? Or is it some parallel super-physics that can traverse through time and space and they get fed back faster than the speed of light? It's all gobbly-gook.
While I love science and these brilliant people, they come up with their theories to expand on other theories and then try to prove it through math. They'll never know. Like I said, what happened to "string theory"?