I saw a program not too long ago that revealed that NASA was disassembling its last Saturn V rocket (on display in Huntsville) so that the agency can reverse engineer it for this new project. Although NASA has Von Braun's original plans for the Saturn V, many of the original contractors are out of business and taken their knowhow with them, and it seems that NASA has forgotten exactly how to build a moon rocket. They know what the individual parts are, but don't know how or why they work.
Truly sad....