Overall view of where the removed auxiliary tunnel would have been mounted, on
the side of the LH2 tank and forward skirt.
Picture 2 of 2.
The four round holes under the auxiliary tunnel are presumably attach points
for the cold
helium sphere mass simulators. (This particular S-IVB is the dynamic
test vehicle, which means that it was built differently from a flight stage,
including the use of mass simulators in place of certain flight hardware; refer
to the Model
Specification, Saturn S-IVB-D Stage for additional