You're paying for provably guaranteed reliability. When you're paying billions per rocket launch, you simply can't afford to have your robot break down on day

You're paying for provably guaranteed reliability. When you're paying billions per rocket launch, you simply can't afford to have your robot break down on day 1 because of a software bug or because a component was accidently installed upside down. (Also, "only gotta make it to the moon" makes it sound like that's a trivial task. There's a lot to unpack in that small sentence.)