Apollo 8 was the first manned flight of the Saturn V rocket. Bill and his crewmates Frank Borman and Jim Lovell were positioned at the very top of the mighty rocket. The biggest surprise to Bill was the violence of the lateral shaking as the F-1 engines gimballed back and forth to keep the giant rocket pointed in the right direction.
The Saturn V rocket was used by NASA and Skylab from 1967 to 1973, and still holds the record as the largest and most powerful launch vehicle ever brought to operational status. 13 launches were made by NASA from the Kennedy Space Center without a single loss of crew or payload.