Western reporting agencies have been banging on about the continued failure of North Korea’s Musudan 25 (Huangsong-10) missile launches. But unless they blow up on the launcher, they probably aren’t complete failures.
That missile is a North Korean adaptation of the Russian SLBM R-27 Zyb which was in use on Russian subs from 1968 until 1988 until it was removed from service as being obsolete and too dangerous to use. Russia sold a bunch of them to North Korea and Iran and Iraq in the ’90s to play with. They were called ‘Scud C’. They are still obsolete and unreliable, and dangerous because they are liquid fuel rockets, not well-suited for mobile transport – which is how North Korea is using them.
The follow-on multi-stage missiles, KN-8 and KN-14 are also liquid-fueled in the first two stages.
North Korea figured out that liquid-fuel ICBMs take a lot of time to fuel and aren’t very reliable. So they are using their old Musudan rockets as test beds – primarily to find a light heat shield for a nuclear weapon re-entry – but also to test flight controls and other modernizations to convert to a solid fuel system.
It really doesn’t matter if the rocket works well or not so long as the sub-assembly under test functions. If it does, the rocket can crash, and is probably designed to do so, and the west can prattle on about North Korea’s inability to develop a functional rocket, having seen what it wants to see.
North Korea needs to replace their liquid-fuel hardware and infrastructure. Using their old Musudans as test beds is a cheap and easy way to test new hardware while concealing it in old systems which don’t have a tactical value anyway, and to make room for a new generation of ICBMs.
Another lingering rumor suggests that Iran is subsidizing North Korea to test missiles for them. I doubt it but, although information and hardware are certainly being exchanged, North Korea and Iran aren’t the primary danger to the world.