Re: Why are the shuttle/Mir astronauts' voices not in sync with their months?

My professional opinion is poor engineering. Presumably voice and video signals from Mir are on separate channels, and someone has not bothered to synchronize them properly.

Since both voice and video will be transmitted as electromagnetic radiation (radio or microwaves), this is not related to the common "delayed-sound-at-a-distance" effect, in which a spectator in a baseball stadium sees the hit before hearing the bat hit the ball. The delay in that case is caused by the fact that light travels very much faster than sound. But again, in the case of Mir the audio and video signals are both being transmitted as radio or microwaves, and so should arrive on the ground at the same time.

It is probable that the astronauts (even the American one!) on Mir are speaking Russian, and the voice you hear is a simultaneous translation. Of course, this would not be the case if you had the lack-of-lip-sync problem in a live shuttle broadcast.