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Detail of the bottom of the S-IVB stage as it sits.

In this view, the mount points for the main tunnel are clearly visible. Also note the sections from the S-IC's cable tunnels standing upright behind the stage; presumably, they have recently been painted.

This is S-IVB-D, the dynamic test stage. If this were a flight stage (or even a more flight-like testing stage), I would have expected to see the cold helium line. However, the Model Specification, Saturn S-IVB-D Stage reveals that each cold helium sphere on that stage is simulated with a "dummy mass," so the stage lacks the plumbing associated with the propellant pressurization system.