>where mass is the dominant cost factor. The compounding importance of mass is one factor here, but only half the story. The other half is how SpaceX' quick it

>where mass is the dominant cost factor. The compounding importance of mass is one factor here, but only half the story. The other half is how SpaceX' quick iterations and ability to retire vehicles early allows ample room to experiment and also to shave off safety factors. In the more mundane aerospace engineering mass is quite important, but the manufacturing, servicing, longevity etc. are pretty important considerations too. A typical airplane is designed for manufacture of some 200 ... 2000 units and to remain in use for 1 ... 3 decades. This, together with the usual requirement for human flight ratings, ends up dictating rather high safety margins for designs. Contrast that with SpaceX' vehicles which are supposed to perform a dozen unmanned flights each at most, and where one-way mission of a vehicle is a perfectly feasible strategy for testing while still making decent revenue. Quick iterations get shit done in aerospace. Among historical examples, that's how MacCready's Gossamer Albatross[1] record-breaker came to be, where other teams failed. -- [1] https://en.wikipedia.org/wiki/MacCready_Gossamer_Albatross https://en.wikipedia.org/wiki/MacCready_Gossamer_Albatross