While browsing concepts of Space Station Freedom and other '80s NASA concepts (I love concept art), I noticed that there are some interesting differences in how the Shuttle was intended to dock with a station than in real life. The concepts, noticeably
have no real docking port inside the Shuttle. In fact, the docking adapter is on the station instead of inside the shuttle.
Why would NASA not choose to go with their conceptual design when building the ISS, and how would it have worked? Surely keeping the adapter on the station would increase payload mass/volume, which is pretty critical when building a station.