"upgraded J-2 second stage" . "S-IVB" . . "S-4B" . "S-IVB" . . "Saturn S-IVB" . "third and last stage" . . . . "Saturn S-IVB stage" . "S-IVB stage" . "third" . "S-IVB#Auxiliary Propulsion System" . . "third stages" . "S-IVB#Derivatives" . "S-IVB-200" . . . .