Workmen inspect a J-2 engine at Rocketdyne's Canoga Park, California production facility. The J-2, developed under the direction of the Marshall Space Flight Center, was propelled by liquid hydrogen and liquid oxygen. A single J-2 engine was used in the S-IVB stage (the second stage of the Saturn IB and third stage for the Saturn V) and a cluster of five J-2 engines was used to propel the second stage of the Saturn V, the S-II. Initially rated at 200,000 pounds of thrust, the J-2 engine was later uprated in the Saturn V program to 230,000 pounds.