Something absolutely crazy about Apollo lunar module was that it couldn’t be flight-tested before use. The first time each lunar module got a shakedown flight was the moment it was being used in space. It also meant that the astronauts flying the lunar module could only ever learn to fly it using simulators. So how do you make sure something that can’t be tested is safe?
At Grumman, the company that designed and built the lunar modules at a factory in Bethpage, Long Island, one part of the answer was: Every single failure of every single component had to be investigated, understood, and resolved. The philosophy, in engineering parlance: There are no random anomalies.
It is an ethic that ended up permeating the entire lunar module effort: Anything that went wrong with any part or system could spell disaster in space. Therefore, anything that failed on Earth had to be resolved and solved. If there were no random failures, then every failure is, in fact, a test, and even more, a gift: With a vehicle that would only fly once, the only place to find and fix problems was before that first flight.
Take a look here to get the inside scoop on the epic mission to create the flawless Apollo lunar module, and how the work ethic behind has permeated work culture down on Earth.