[JDulin]

One problem with these hypersonic endeavors and 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. Instead, there are low-single-digit numbers of tests with tons of political attention ready to pounce at the smallest (And most common!) failure.

[wongarsu]

A lot of the success of SpaceX can be attributed to their rapid incremental development model that they established with Falcon 9 and continued with Starship.

But at least with civilian rockets all the competitors have clear success metrics: they all launch with some regularity, and it's obvious if those launches were a success. Lots of weapon systems have one or two tests and then take a decade before they see any action, if at all.

Fore example the Patriot system is operational since 1981, but when first used in combat a decade later its accuracy came under heavy scrutiny, and continues to look suspect on a per-missile basis [1]. But that's one of the weapons systems that actually sees active combat, and sees improvements based on that. Now think of all the systems that are deployed but never used.

1: https://en.wikipedia.org/wiki/MIM-104_Patriot#Operational_hi...

[jandrese]

It should be noted that the Patriot was being used outside of its original design goal when tasked with shooting down missiles. It was designed to shoot down Soviet interceptors, but had to pivot when the Soviet Union collapsed. Missiles were a stretch goal of the original project, but ended up being its primary mission.

[jvanderbot]

And in particular, many of the failures were from lack of proper operation, such as keeping the system on far too long, causing timer overflows.

https://www-users.cse.umn.edu/~arnold/disasters/patriot.html

[jasonwatkinspdx]

Yeah, one last point on this subthread is, the modern Patriot system is also not at all the same beast, with a lot of upgrades in the decades since.

[jjoonathan]

If I were a company in this space, I would try to keep my tests secret for exactly that reason. If I was successful, they would not be available for scrutiny by hacker news.

Public tests are still independently necessary and failing them is still an embarrassment, of course.

[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.

[chmod600]

In other words, if you aren't actively using a weapon in real war, it probably will fail when you try.

Kind of like the Russian ground forces in Ukraine. They hadn't fought real ground wars in a while.

Not sure what this says about humanity. But it certainly raises questions about how to maintain a defensive force. The answer, unfortunately, might be to have a series of small wars just to keep in practice. Even then, the knowledge gained might not translate well to a large war.