Not an engineer. Just an old numbers cruncher. But it seems to me it’s impossible to have an expected failure rate of all the mission critical parts of some machine be precisely equal to zero out to however many decimal places you’d like. And the larger and more complicated the machine in question, the more frequently you’re going to see a sudden catastrophic failure of some kind.
So it makes me nervous when they start talking about.. “Let’s build this big complicated rocket ship, put a whole bunch of people on it, and blast it off into outer space.” lol
Challenger space shuttle. Three orings failed. Predicted. Happened. Crew and a school teacher spread all over the Everglades. NASA.