Overall view of the aft end of the S-IVB, including the J-2 engine, ambient helium
spheres, and O2H2
burner (aka "helium heater").
Picture 2 of 2.
I last visited KSC before I knew what a O2H2
burner was, and so I have no more detailed photos of it on this S-IVB stage,
but see the pictures of the helium heater in my Johnson Space Center
S-IVB picture set.