"Safety factors started being formalized in the mid-1800s for bridge building, where factors as high as 6 were used to cover for the massive inconsistencies in

"Safety factors started being formalized in the mid-1800s for bridge building, where factors as high as 6 were used to cover for the massive inconsistencies in the quality of early cast iron." I'm not a real Civil Engineer but I was a graduate one from 1991 - I'm now a IT bod. Anyway, Civ Eng uses established factors of safety or safety multipliers or safety factors or whatever. Structural steel uses 1.2 I recall - so you work out your worst case (in 100 years - look up tables) bending moment and mult by 1.2. Civ Eng is one thing and despite our bridges still failing after 2000 years of really solid knowledge. Tacoma Narrows (who knew the bloody things fly and shake) or London Millenium bridge - lol - shake, shake, shake the room - BOOM. The thing about safety factors is that they need to be derived conclusively. In Civ Eng - wood is a bit wayward so the safety factor for it is quite large compared to steel. I have no idea what you do for space thingies (yes I do) but I would expect my first 50 experiments to blow up - I need to explore the extremities. If I ran a Space Agency I would say something like: "Soz, we are going to make some cracking firework displays first and then we will know what to avoid."