This image depicts the test firing of a J-2 engine in the S-IVB Test Stand at the Marshall Space Flight Center (MSFC). The J-2, developed by Rocketdyne under the direction of MSFC, was propelled by liquid hydrogen and liquid oxygen. A single J-2 was utilized in the S-IVB stage (the second stage for the Saturn IB and third stage for the Saturn V) and in a cluster of five for the second stage (S-II) of the Saturn V. Initially rated at 200,000 pounds of thrust, the engine was later upgraded in the Saturn V program to 230,000 pounds.