There's a nice parallel there to the construction and launch of individual rockets, as described in another story on the homepage[1]. Many rockets are essentia

There's a nice parallel there to the construction and launch of individual rockets, as described in another story on the homepage[1]. Many rockets are essentially designed to be single-use, so they can't be put through too much stress during testing. Therefore missions are essentially flown with completely new, largely untested rocket hardware. The work-around is to build two identical copies of the rocket. The first is a test unit which is tested to failure; the second is put through a very brief test to confirm that it appears to behave sufficiently similarly to the first, and then it's put into service. [1]https://news.ycombinator.com/item?id=8060031 https://news.ycombinator.com/item?id=8060031