To most Americans, especially those of us who used to work at NASA, Neil Armstrong’s death was the loss of an American hero, and a sad ending to our Moon exploration days. But the reason we mention the astronaut in today’s blog is his speech about the topic of Chapter 17, reliability. Surely someone who risked his life in every launch and who studied engineering understood the mathematics of reliability.
As reported in The Wall Street Journal (Aug. 26, 2012), here are Armstrong’s remarks: “Each of the components of our hardware were designed to certain reliability specifications, and far the majority, had a reliability requirement of 0.99996, which means that you have four failures in 100,000 operations. If every component met its reliability specifications precisely, a typical Apollo flight would have about 1,000 separate identifiable failures.”
“In fact, we had more like 150 failures per flight, substantially better than statistical methods would tell you that you might have. I can only attribute that to the fact that every guy in the project, every guy at the bench building something, every assembler, every inspector, every guy that’s setting up the tests, cranking the torque wrench, is saying, ‘If anything goes wrong here, it’s not going to be my fault, because my part is going to be better than I have to make it.’ And when you have hundreds of thousands of people all doing their job a little better than they have to, you get an improvement in performance.”
I appreciate Armstrong’s observations–and think your students may as well. In those days, you could stand outside a NASA Space Center and never tell when quitting time was. Engineers simply stayed each day till they felt their work was done–maybe at 6 pm or even 9 pm. When we work on projects we are all interested in and dedicated to, there is nothing we cannot accomplish.
Discussion questions:
1. What was the reliability of each Shuttle flight, given that 2 Space Shuttles crashed in about 140 flights?
2. In what other industries is reliability equally important?