The S-IVB was the third stage on the Saturn V and second stage on the Saturn IB launch vehicles. Built by the Douglas Aircraft Company, it had one J-2 rocket engine. For lunar missions it was fired twice: first for Earth orbit insertion after second stage cutoff, and then for translunar injection (TLI).
S-IVB-206 which was used for the Skylab 2 flight
Cutaway drawing of the Saturn V S-IVB
Apollo 7 S-IVB in orbit over Cape Canaveral.
Distant view of Apollo 7 S-IVB stage
The Saturn V is a retired American super heavy-lift launch vehicle developed by NASA under the Apollo program for human exploration of the Moon. The rocket was human-rated, had three stages, and was powered by liquid fuel. Flown from 1967 to 1973, it was used for nine crewed flights to the Moon, and to launch Skylab, the first American space station.
The launch of Apollo 11 on Saturn V SA-506, July 16, 1969
Saturn V testing vehicle and flight vehicle configurations
Von Braun with the F-1 engines of the Saturn V first stage at the U.S. Space and Rocket Center.
All Saturn V launches, 1967–1973