 The Apollo 8 spacecraft was placed on top of the rocket on September 21 and the rocket made the slow 3 @-@ mile ( 5 km ) journey to the launch pad on October 9 . Testing continued all through December until the day before launch , including various levels of readiness testing from December 5 through 11 . Final testing of modifications to address the problems of pogo oscillation , ruptured fuel lines , and bad igniter lines took place on December 18 , a mere three days before the scheduled launch . 
