|astronautix.com||First clustered firing of Saturn V's first stage|
MSFC conducted the first clustered firing of the Saturn V's first stage (the S-IC). The booster's five F-1 engines burned for about 6½ seconds and produced 33,360 kilonewtons (7.5 million lbs) thrust.
Eight days later, at its static facility in Santa Susana, California, North American first fired the S-II, intermediate stage of the Saturn V. The event was chronicled as the "second major Saturn V milestone" during April.
George E. Mueller, Associate Administrator for Manned Space Flight, emphasized the significance of this test, calling it "one of the key milestones in the whole lunar landing program." References: 16 .