That's quite the image and it got me to go back and re-examine my stock of images. No door was ever 50" wide though Thanks to the screencaps provided by @BK613 it is clear that the original door height was intended to be 6'6" and that is what was maintained on the Bridge set throughout the series. However, it is equally clear that when Star Trek went to series and the main sets were built, the door heights were raised a little (perhaps due to Nimoy's height?) It's clear that ALL the door heights were raised due to scenes like this: A good screencap to demonstrate Shatner's height is this one from Corbomite as he was wearing slippers at the time rather than his heeled boots The turbolift door width of 3'6" was adhered to fairly consistently in Season One so we can rely on that as a measurement. This would put a gap of around 12" above Shatner's head. His height has been quoted as low as 5'9" on some sites which would make the door 6'9" as he is basically barefoot in this scene! I am now fairly convinced that the set doors were all 6'9" tall which might explain some of the problems I had in deciphering the panel sizes last year!