I want to add: If you look at the tools and theoretical underpinnings spaceX uses to develop their vehicles, they didn't develop them themselves. Numerical sim

I want to add: If you look at the tools and theoretical underpinnings spaceX uses to develop their vehicles, they didn't develop them themselves. Numerical simulation methods, especially for hypersonic flow, powder-bed fusion, CAD etc. - those were invented by other people and for the most part all of the numerical methods involved come from DoD work, where they were first developed and verified. FEA? DoD. Finite-Differences? DoD. All kinds of clever methods for mechanical/thermal/optical simulation? DoD. It's almost sad how much of modern engineering depends on that basis. Edit: If you look at old papers for numerical methods, especially in wave optics, most of the time you see a fighter or a bomber in the results - gotta estimate that radar cross-section for when the cold war gets hot.