Protective closure assembly for the Rocketdyne F-1 rocket engine's turbopump oxidizer inlet, measuring 18.5″ in diameter, marked with part no. "RX-20633-25H." Includes an unused 6″ Rocketdyne decal and a parts list and diagram showing the location of the closure on the F-1 engine; its purpose was to provide better protection and reduce the possibility of foreign objects entering it during handling and use. The F-1, used to power the S-IC first stage of the Saturn V launch vehicle, remains the most powerful single combustion chamber liquid-propellant rocket engine ever developed. In fine condition.
