Lessons from NASA: Design reviews, failure analysis, and redundancy are favored over predictions and life testing for spacecraft success

Spacecraft differ from other products of technology in several critical respects. They are exposed to hostile environments unlike any on earth. They cannot be repaired once they are launched. Production of a particular craft has been limited to one or at most a few models. The designs challenge the state of the art and use the latest hardware, which must be proved for the space environment by thorough testing.