The turbine exhaust port on the wall of the aft
See also my photo of this
port on the outside of the missile on my Juno II page.
See also my photos of the turbine
exhaust/roll control duct on the USSRC Jupiter missile.
See also my photos of the S-3D engine's
turbine exhaust duct on the inside the tail unit
of the Jupiter missile at
Air Power Park.