Encyclopedia entry CZ-2-1 stage series Original archive entry. The text, images and links below are kept as they were written. SubtopicsFB-1-1 N2O4/UDMH propellant rocket stage. .CZ-3A-1 N2O4/UDMH propellant rocket stage. .CZ-2C-1 N2O4/UDMH propellant rocket stage. .CZ-2E-1 N2O4/UDMH propellant rocket stage. .CZ-3-1 N2O4/UDMH propellant rocket stage. .CZ-4A-1 N2O4/UDMH propellant rocket stage. .