A great big boom
Saturnís fury: effects of a Saturn 5 launch pad explosion
The Saturn 5 was the largest rocket ever built by the United States. A true monster of a launch vehicle, it generated over 33 million newtons of thrust at liftoff and carried 2.5 million kilograms of fuel and oxidizer. If the Saturn 5 exploded, it could do so with the force of a small atomic bomb, the equivalent of half a kiloton, or about 1/26 the size of the bomb that destroyed Hiroshima. Naturally, this was a significant concern for Apollo program officials.
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