Re: What is the white stuff that falls off the Apollo rockets upon launch?

The "white stuff" you ask about is simply ice falling away from the main 
engine's fuel tank ( that big, red round thing beneath the spacecraft).  
The tank is filled with liquid hydrogen which is very cold.  The ice comes 
from the humid air of the Atlantic coastline.  It freezes on the fuel tank 
the same way beads of moisture form on a cool drink you might pour 
yourself from the refrigerator.

Good question.  Keep Questioning things.