Moon Machines: The Lunar Module. It's amazing they succeeded, never mind survived. The lunar module booster rocket could only be fired once because of the corrosive properties of the fuel. Imagine trusting the rocket to fire while knowing if it didn't you would die on the surface of the moon. To save weight the ladder that made it onto the landing strut was originally supposed to be a rope/pulley system. "One giant tug for mankind" just wouldn't have sounded the same.