Rare Saturn V Third Stage (S-IVB) J2 Rocket Engine primary hydraulic assembly responsible for steering the stage's main engine. Assembly measures approximately 32″ long and 10″ high. The NASA Marshall Space Flight Center label is affixed to one end, with an “XN,” etched on to the label. The artifact is displayed on a custom wooden stand with an informational plaque affixed to the base. In fine condition. When commanded by the onboard flight computer, this Accumulator-Reservoir provided the fluids to the rocket engine's actuators resulting in deflection (a change in the orientation of the engine) to alter the trajectory of the Saturn V and the attached Apollo Command Service Module along its flight path. RR Auction COA.