S-IVB-505 and S-IVB-211, the flight version of the S-IVB stages, in the McDornell Douglas' S-IVB Assembly and Checkout Tower in Huntington Beach, California. As a part of the Marshall Space Flight Center `s "building block" approach to the Saturn vehicle development, the S-IVB stage, in its 200 series, was utilized as the Saturn IB launch vehicle's second stage, and, in its 500 series, the Saturn V's third stage. The S-IVB was powered by a single J-2 engine, initially capable of 200,000 pounds of thrust.