S-IVB (rocket stage)
was a Saturn
It was used as the third stage of the Saturn V rocket and the second stage of the Saturn IB rocket.
A derivative of the S-IV, the S-IVB had one J-2 engine which produced a thrust of 200,000 lbs.
The S-IVB carried 72,700 liters (20,000 gallons) of LOX and 229,000 liters (63,000 gallons) of LH2.
An un-used S-IVB provided the hull for Skylab, the United State's first space station.
The S-IVB was built by Douglas Aircraft Company.
During Apollo 13, Apollo 14, Apollo 15, Apollo 16 and Apollo 17, the S-IVB was crashed into the Moon in order to perform seismic measurement used for characterizing the lunar core.
Three versions of the SIV/SIVB