> Since all the design and tool-up costs are sunk, why not build two or three? Even just as components. a huge chunk of the cost of "building" a spacecraft is

> Since all the design and tool-up costs are sunk, why not build two or three? Even just as components. a huge chunk of the cost of "building" a spacecraft is all of the testing, calibration, integration, validation, etc etc that goes on after the physical objects are assembled. yeah, the machinists can crank out a second housing or structural element for nothing after they've made the first one. the electronics assembly techs make a handful of most every board, to start with. but only one set of all of them is handed back to all the principal investigators to go through the months/years of prep work necessary to ensure the physical assembly that's been produced will function correctly, for years, on orbit.