think there were 5.6 million parts on what they called the stack, okay, it included the command module, the service module and of course the lunar module which landed and then everything of course in the saturn five rocket. the engineers strove for something called the 99.9% liability rate. it meant that if .1% of things went wrong, you had 5600 parts would could potentially fail. it took a lot of guts to be able to sit on that rocket. >> neil: to absorb the risks. the apollo fire, within two and half years we would make it to the moon. we would complete the goal. that would've been unthinkable. >> it would've been unthinkable. you are absolutely correct. what all the astronauts told me