Karl Gallagher as some thoughts on how too many requirements can kill a program. This happened to both Shuttle and station.

Unfortunately, because the way NASA has traditionally done things is so expensive, the assumption is made that they can only afford one of them (a National Space Transportation System, a national space station). That means that multiple requirements (often, or usually, conflicting) tend to get laid on them, to satisfy all of the political constituencies. The program as a result bloats, and becomes very expensive (in time and money), making the original assumption a self-fulfilling prophecy.