[trhway]

I think keeping actual hypersonic flight tests secret is pretty hard. At least in IR they should be very well visible from space.

>DOD development in general is there are too few tests (And done too slowly) to iterate. The developers do not get lots of opportunities to learn from real-data, like at SpaceX

i suppose cost is among the major reasons. The SpaceX had an objective to take the cost down which is synergetic/self-enforcing with the many tests and iterations approach. DOD is opposite - the goal for the contractors is the smallest number of tests done at the highest billed price to DOD as that maximizes the contractor's profit.