This image depicts a firing of a single H-1 engine at the Marshall Space Flight Center’s (MSFC’s) Power Plant test stand. This 1950s test stand, inherited from the Army, was used to test fire engines until the Test Area was completed in the latter 1960s. The H-1 engine was the workhorse of the first Saturn launch vehicles and used in the Saturn I, Block 1 and II, and in the Saturn IB. The eight H-1 engines were attached to a thrust frame on the vehicle’s aft end in two different ways. Four engines are rigidly attached to the inboard position and canted at a three degree angle to the long axis of the booster. The other four engines, mounted in the outboard position, are canted at six degrees.