I find it very disconcerting that Kim Jong-Un keeps firing those duds. My concern is that one of these times he's going to fire one and it won't be a dud and it won't explode over N. Korean territory.
I think his repeated "failed" tests are feints to lull folks into greater degrees of insouciance. I think that because in this day and age, what it takes to get a missile to launch successfully isn't beyond the capability of all sorts of engineers and physicists. The miniaturization requirements for an nuclear tipped ICBM may well pose some challenges, but firing off an ICBM missile that can reach halfway around the world should not.
Briefly checking to make sure my supposition is on target, I came across this:
There are two challenges that designers have to face: designing the warhead and designing the missile .
A nuclear warhead can be carried by ICBMs/SLBMs , IRBMs , cruise missiles and of late even TBMs . You have to take into account the type of missile before deciding what type of nuclear warhead it can carry .
There are at least 5 layers in any modern day nuclear warhead ( from top to bottom) :
- The Primary Layer
- The Secondary Layer
- Radiation Case
- Channel Filler
- Booster Gas Cannister .
Designing each of these stages comes with it's own set of challenges . The warhead should be insensitive and use fire resistant explosives, have a fire resistant Pit , foolproof permissive action link , strong link weak link detonation chain safety mechanisms and two-point explosive lens assembly.
Now , let's assume that the delivery vehicle will be an ICBM . The biggest challenge is the development of a 3 stage Solid propellant rocket motor .
The mass of the booster increases with the missile’s range. So a 1-ton warhead requires an approximately 5-ton missile.The primary way to increase the range of a missile is to make it larger and add propellant.The additional propellant and missile structure increase the missile’s mass. As a result, the engines need to accelerate all this additional mass as well as the original mass of the missile and payload, so the increase in missile size gives you much less increase in range than you might expect .
Building a single stage ICBM is extremely difficult . Building a 2- 3 stage ICBM , somewhat easier .You have to get staging right, and getting it right in your first attempt is very difficult .
Another very important aspect that designers have to accommodate in the design of the missile is low drag re- entry .This is necessary if the idea is to defeat terminal-phase missile defenses and probably necessary if you want the accuracy needed to engage hard targets.
I don't know and cannot say that what the writer shared is accurate, but I can say it aligns with the rudimentary physics and engineering ideas of which I'm aware. Assuming the above narrative is on point, I'm curious to find out what is "failing" in the N. Korean missile tests. It'd be nice to know what the test objective(s) are too, but I know I'm not going to be made privy to that information.