I have a question about the 8' model used in the movie. TMP remains the only occasion where we actually saw any of the hero ships depicted with open hatches (other than the shuttle bays). Indeed the refit Enterprise seems to be unique in that it was covered in surface details that indicated hatchways though most were never used. I am, however, curious as to what was supposed to be under those hatches. We know one was an airlock (which always struck me as an odd place for one). What were the other 2? Was the model actually built with these openings?