Saturn Apollo Program

This cutaway of the Saturn I S-IV stage (second stage) illustrates the booster's components. Powered by six RL-10 engines, the S-IV stage was capable of producing 90,000 pounds of thrust. Development of the Saturn S-IV stage by the Marshall Space Flight Center (MSFC) contributed many technological breakthroughs vital to the success of the Apollo lunar program, including the use of liquid hydrogen as a propellant.