>Maybe they did both things, and the weld still failed. The rocket's being engineered, which means they make it as weak as possible without it blowing up. Those

>Maybe they did both things, and the weld still failed. The rocket's being engineered, which means they make it as weak as possible without it blowing up. Those welds might be perfect in the x-rays, they might've done all sorts of destructive analysis, and still the thing might fail in staging. Yes, that is also a possibility. I'm not sure how likely is it that a pressure vessel would fail along a weld if that weld was without faults and as strong as other surfaces. Perhaps it matters that there is also a sharp corner there? >Of course, they might also be on a deadline, and just went ahead and built it to spec and test it. But I don't think you can just say there's routine testing procedures that ensure rockets never blow up. I agree if they are trying to make it as light as possible and pushing the boundaries a bit while experimenting. One can't innovate without risk. It would be good if they released more info about this incident.