 North American shipped spacecraft CM @-@ 012 to Kennedy Space Center on August 26 , 1966 under a conditional Certificate of Flight <unk> : 113 significant incomplete planned engineering changes had to be completed at KSC . But that was not all ; an additional 623 engineering change orders were made and completed after delivery . Grissom became so frustrated with the inability of the training simulator engineers to keep up with the spacecraft changes , that he took a lemon from a tree by his house and hung it on the simulator . 
