3 ms·

It also means costs and estimates are incorrect and a potential waste of public resources

• acdha 3y ago
  Again, nothing is incorrect here: a margin is only waste if you’re a Walmart MBA obsessed with lowering costs. If the DOT builds a bridge with a 70 ton rating and it doesn’t collapse when an 80 ton truck drives over it, that’s not waste but rather the engineers prudently including a safety margin in each component to protect against minor defects or inconsistencies meaning that one component being slightly under spec causes the entire system to fail. NASA and aerospace as a field traditionally have a bias towards that kind of overlapping safety margins because the kinds of failures they get destroy the entire air/space-craft. If some MBA at GE cost-optimizes your dishwasher, they’re better off trimming “waste” until it dies the day after the warranty expires as long as it doesn’t fail in a way which causes you never to buy their brand again. NASA faces far more catastrophic failures and because their systems are all custom with economy of scale for large product runs and their missions by necessity have a hefty base cost so it doesn’t make sense to save $50k on rover parts when you are paying $500M to ship it to Mars.