Apollo 11 - Close-up View of Launch

As the F-1 engines of the mighty Saturn V rocket roar, Apollo 11 ascends. Windows throughout a three-mile radius shake as three astronauts begin their journey to the Moon. It is July 16, 1969.

These NASA close-up views show huge pieces of ice as they fall to the ground during launch. How could this ice exist on a hot summer morning?

The Saturn V is fueled with liquid hydrogen and oxygen which is extremely cold. As noted in a NASA Press Release (dated the 14th of July, 1969) discussing (among other things) how engineers developed the rocket's propulsion systems:

Over the course of the next decade [mid-50s to mid-60s], rocket engineers and scientists experimented with a variety of thrust chamber designs to achieve high combustion efficiency and smooth burning; and they measured heat transfer rates within the thrust chamber and demonstrated how to cool the chamber and nozzle with liquid hydrogen.

Since hydrogen, the lightest of the elements, in its liquid state boils at -423 deg F, and the oxidizer, liquid oxygen, is stored at -29 deg F, another major concern was how to handle the cryogenic propellants themselves.

As a result of these extremely cold liquid-fuel temperatures, the body of the rocket also cools, causing atmospheric humidity surrounding the Saturn V to convert into ice.

During launch, as the F-1 engines roar and vibrate - shaking windows within a three-mile radius - the ice breaks apart and falls away.