> 3) Lots of Apollo era designs don't exist on paper. The F1 engine doesn't really even have a standard design, since every iteration was changed to be "better"

> 3) Lots of Apollo era designs don't exist on paper. The F1 engine doesn't really even have a standard design, since every iteration was changed to be "better" by throwing shit against the wall and seeing what sticked. I believe the F-1 specifically does have full CAD models now after a reverse engineering effort, though in general your point still stands. They attempted to restart J-2 production for Ares, but ran into so many complications that the J-2X was basically a clean-sheet design