North Korea’s Small SLBM

Jeffrey Lewis 0:06

You are listening to the Arms Control Wonk podcast, a podcast on arms control, disarmament, and non-proliferation. I'm Dr. Jeffrey Lewis, the founding publisher of the Arms Control Wonk blog and a professor at the Middlebury Institute of International Studies at Monterey. Since North Korea did a test of a submarine-launched ballistic missile, we had no choice. There is only one thing we can do, and that's invite our friend Joseph Dempsey, a research associate for defense and military analysis at the IISS, on to talk North Korean boats, rubber duckies, and whatnot.

How you doing?

Joseph Dempsey 0:46

Good to be back, Jeffrey. Lots to talk about.

Jeffrey 0:50

Well, at least two things, right? So my big question for you is, what are you calling that little missile?

Joseph 1:01

Well, we say it's little, it's littler, but I wouldn't call it little by any stretch of the imagination. So, yeah. I initially thought Prokexon, given what it was displayed at alongside last week at the defense exhibition, which is displayed alongside the PK-1 and the PK-5. And yes, in relation to those, it is smaller. However, the imagery that's come out of the launch, the high-res stuff that came out slightly later, it looks a lot like the KN-23.

Jeffrey 1:33

In which case- Oh, that's interesting. So you think it actually may be a navalized version of the KN-23?

Joseph 1:40

Yeah, certainly. I mean, it's early days to really assess that, but just looking at it, looking at the launch pictures, The dimensions or at least the proportions certainly look very much like KN-23. From what North Korea has said and the reporting of the flight paths, it would also indicate similar performance of KN-23.

Jeffrey 2:03

Yeah, and so by reporting of the flight path, you mean that the apogee was relatively low at 60 kilometers and then the thing went about, what was it? Was it 590 kilometers was the final?

Joseph 2:15

That's the upper estimate, yeah. So, yeah, the press trajectory, as you said, which is typical of some of the short-range ballistic missiles that North Korea has demonstrated since 2019. And, yeah, when they talk about the – I forget the exact words. Oh, here, I've got it. It says –

Jeffrey 2:34

That the task clarified that the new type submarine-launched ballistic missile, which introduced many developed controlling and homing technologies, including the lateral movement and gliding and jumping movement, will make a great contribution to further developing the defense technology of the country and improving the underwater operation capacity of the Navy.

Joseph 2:56

I got flank mobility and gliding skip mobility I introduced on my... Version, that's KCNA, sorry, including flank mobility and gliding skip mobility are introduced.

Jeffrey 3:10

I wonder if somebody did a quick and dirty translation that they put online.

Joseph 3:15

That's coming from KCNA directly on the English translation I would have used.

Jeffrey 3:20

Yeah. So I'm guessing that that is then my copy is from VOA. So maybe they just went ahead and translated.

Joseph 3:28

Anyway, what's a skipper? Sorry.

Jeffrey 3:33

Where were we? How do we get back to where we, Oh, I think just by reading it, we can just go in there. I've got it. Okay. But you could read yours because you've got, I kind of like, I like skip better than jump.

Joseph 3:45

Okay. Yeah, and it's also kind of, in the Norfolk statement, they kind of indicated it had advanced guidance technologies, including flank mobility and gliding skip mobility that they introduced. Now, obviously, some of those are quite grandiose terms, and I'm not entirely sure how to interpret them. Basically, it's some kind of mid-course maneuverability, potentially a pull-up maneuver, which we've seen from the KN-23.

And even some of the discrepancies in the ranges initially reported may also point towards that as well.

Jeffrey 4:13

So I'll own up. The folder that I've created for this in my missile library on Google Drive is navalized KN-23. But were you confident of that from the close-up picture we got at the Defense Expo? Or do you think that there are some differences between the article we saw at the Defense Expo and the thing they just popped up out of the water?

Joseph 4:38

Yeah, good question. So when I first saw the Defence Expo, I would have said not thinking KN-23 initially. And part of that was because it didn't have... The control surfaces associated with KN-23, visible at least. It had what appeared to be grid fins. And obviously we only kind of saw it from head to tail in that kind of perspective.

So we didn't get a really good look.

Jeffrey 5:03

It's a terrible angle for a missile.

Joseph 5:05

As somebody who models them, it's incredible how much foreshortening there is. It is. And obviously, you know, it helped that we had PK-1 next to it. It gave us a much better sense of scale of it. But yeah, I wouldn't have put it, said it, say it's the KN-25 had seen it and had these blisters. And also the fact that it had this kind of what appeared to be quite a big base plate, which we can see, both see from the expo and the launch, you know, implied that because it's a smaller missile, it's probably going to fit in the same tube as the PK-1, which is what I think it did do, by the way.

And we'll probably get onto that, I imagine. Yeah. But when we saw the actual, the launch imagery, and I was taking it as that is accurate and not being manipulated, the proportions of the missile, again, we don't do minteration, but the proportions match very clearly to KN-23, right down to the tail fins as well. We didn't see grid fins on the missile, but they may have been part of the kind of the ejector base or the base plate or the ejector system.

Jeffrey 6:02

Oh, I'm totally going to make a graduate student measure it. That's...

Joseph 6:08

So yeah, I do wonder, yeah, going back, sorry, going back to the original point is, is it the same thing? And I do have some kind of doubts that exactly is it the same thing we saw kind of at the defense expo? I think potentially some of the ejection system at the bottom and how the fins may be stored and what the fins are.

I think that might be some difference between... The article that was launched and the presumed mock-up we saw last week?

Jeffrey 6:34

Yeah, I would say that when I was looking at the high-resolution image, the petals on the ejection plate, it looks like there are more than four. And so my working hypothesis is that those blisters pop down. And that the grid fins are stuck to the base plate. So that nicely explains the grid fins and the blisters, which really threw me for a loop.

So I'm good with navalized KN-23, at least until North Koreans.

Joseph 7:06

That still doesn't answer the question, what do we call it? Because obviously KN-23 is the U.S. designation. We still don't have a name for what they call it, which is quite surprising given that we have seen about five or six different iterations of this missile.

Jeffrey 7:18

Well, also, I would say this is a great example of the failure of the United States to maintain its excellent missile naming patterns, right? Because once upon a time, you would have just stuck an N in there, right? It would have been the KNSSXN, you know, whatever. But as it is, we're just going to get some soulless number.

I like NAM.

Joseph 7:45

I assume it's... It's the wee man. Subscander. That's my favorite. But I mean, probably, I assume it probably has a Howe song designation. So it could be 16. It could be 18, given what we learned. Obviously when they took PK2 ashore, they kept the PK song. So presumably the Howe song can go to sea.

Jeffrey 8:11

Yeah, fair enough. All right, so if it's a navalized KN-23, then we have this issue of the boat.

Joseph 8:20

Yeah, so what North Korea claimed and showed is the Goree-class or Simpoe-B SSB, so ballistic missile submarine. And this is the one they launched circa 2014 and was involved in tests of the Pukosong-1. It was not involved. Are you talking about the Hero submarine? Sorry, yes, it's a new name with a new number. I like that one, Jeffrey.

Jeffrey 8:49

What is it? It's the Hero Submarine, August 24th?

Joseph 8:53

Yes, in reference to, I think, the previous test of the PK-1. So, yeah, the interesting thing about that boat is, you know, it is an SSB. How capable it is? Is it just a trial boat? You know, it can maybe go under its own power. It can go up and down. But beyond that, it just launches a missile.

That's all you're seeing in it. So, yeah. In terms of how capable that system is, always used as a glorified submerged platform. It can't, as far as we're aware, launch PK3, which was launched in 2019, because that is significantly bigger than the PK1. And, you know, to modify the sail, which is what houses the launch tube, we take extensive work, which there's no evidence of that.

So that was launched on the submerged barge. So it always kind of raised the question, well, PK-3 and then PK-4 and PK-5, which are all the large diameter SLBMs, they have no launch submarine for those. Obviously, we thought they're building it. They may still be building it some, but yes, that's an interesting thing. So this, seeing the go all the way back in notional service with a new number and name, and then seeing it being converted to launch this...

Smaller missile. But, you know, looking at the packing on the base plate, it's using the same tune. It's just kind of filling it in the difference.

Jeffrey 10:16

Yeah, that makes a ton of sense to me. I mean, I guess my question is, what kind of submarine do you ultimately expect to see this missile deployed on? I mean, I know that, you know, Kim went and saw that the heavily modified Romeo under construction two years ago and By the way, you and Dave worked out that it was in the building next to the building everyone thought, right?

Joseph 10:43

Yes, we did. So, yeah, just to kind of jump something. It's on Beyond Control Walk.

Jeffrey 10:47

Yeah, but just good for you.

Joseph 10:50

A nice little picture there. That was impressive. So a lot of people looking for the wrong indicators. A barge moved to a certain key, which interpreted as they're going to launch a submarine soon. But then me and Dave looked at the imagery I looked through the windows we'd seen on the inspection of the assembly and said, yeah, that's not going to be launched from the quayside.

It's going to be down a slipway on the older assembly hall next to it. So even, to be fair, even the UN report that came out last week was still talking about the old construction hall. Sorry, the larger, newer construction, I should say.

Jeffrey 11:26

Right. The new old one.

Joseph 11:28

Yes. There's been a lot of refurnishment going on.

Jeffrey 11:32

So Kim looked at the submarine in 2019 that was under modification, construction, whatever the correct word would be. And then I know that in the January speech he gave, he said that they'd completed the refurbishment or renovation of the medium size class submarine. So where does this thing go? Where does the little, where does the wee man or the navalized KN-23 actually end up in their submarine force?

Joseph 12:00

Yeah, I mean, it's a good question. It raises bigger questions about, you know, what is the ambition of Norfolk's SLBM programme or programmes? You know, are we going to see one or more of these? Are we going to see PK5 and this new system fielded at any point? Are we going to see both? Or does it kind of represent a kind of a...

A real dramatic change in direction, something perhaps less ambitious, but more achievable. So with the new missile, because it is smaller and it is relatively proven technology now in terms of the actual missile, because of the KM23, assuming it's related to it, more than known quantity for them and for us. The advantage of the smaller missile means that if you are going to go with the Romeo, then you can certainly pack more missiles into the Romeo missile.

Than you could do with the PK-5, et cetera. The other advantage is that, well, the other kind of query is how viable is the big Romeo? Can they produce effective ballistic missile subs of that size? And that's always a question I kind of pondered, because this is a conversion, and to be sure, we saw it in advanced stage of completion two years ago.

We've not seen it since. We've seen different iterations of the SLBMs that they're graded and displayed. Obviously, one launched previously, the PK-3. It always makes me wonder, are they having problems with that kind of tract? And is it actually more about being able to put them in a boat robustly and launch them, rather than the missile itself?

So this smaller missile, it could also open the way to more realistic, smaller ballistic missile submarines and conversions. Particularly ones that, you know, I mean, I'd have to do some mesuration, but potentially, you know, rather than try to put a launch tube through the sail, could you kind of mount it outside the pressure hole? And then given the relative size of it, could you actually then raise it underwater?

Doesn't it have to be mounted vertically? So it kind of opens some new opportunities, particularly, which may permit easier kind of conversions or newer designs.

Jeffrey 14:15

Well, and so then I think, you know, I have the other question of do we, what do we make of the fact that, you know, there are two other things in Kim's January speech that got my attention. One was, you know, he asserted they were going to complete a nuclear powered submarine, which did sort of cause me to be like, hey, huh?

But then the other thing that was really weird is when Kim Jong-un talked about testing a solid propellant ICBM. He said it would be a solid propellant ICBM or SLBM. And I just, I mean, boy, a solid propellant intercontinental range. Missile sitting on a nuclear powered submarine. Like I've, I've been, I've been like out front on the North Koreans for a while, but even that's like, that's a little much for me.

Right. Like that seems fairly ambitious.

Joseph 15:04

Yeah. I think that's very ambitious. Obviously, you know, get the Romeo to work first. If we'd gone 10, 20 years ago and you know, they say we would have a nuclear ICBM, then, you know, many scoffed and even five years ago, people scoffed. So I never say never with North Korea, but yet it is a massive, ambitious programme.

And I think, you know, it's not going to be any time soon if they ever achieve it. The first, for example, the first ballistic missile service operational won't be that. The first nuclear submarine won't be that either. So, you know, we're talking decades down the line potentially to have an effective, and by effective, I mean it can hide and it can go places beyond territorial waters and it can deploy for months on time.

That's a bigger other issue in terms of submarine operations that they simply aren't at and won't be for... Probably a generation or two.

Jeffrey 15:57

Yeah, I mean, I'm probably biased by my experience, but the Chinese made a big deal about the precise same capability in the late 1960s, and we didn't end up actually seeing that nuclear-powered submarine until the mid-1980s, and then the Chinese built it, and they were like, oh, that sucks.

Joseph 16:13

Yeah, and you can look at the Indian example as well. And didn't build another one for another 20 years. Yeah, and you can also look at the Indian example about their route towards an SSBM. Yeah. Which is ongoing.

Jeffrey 16:23

So... I mean, I find it really I think it's really useful when you say that then that this test opens up this question of like, what is the direction? Because I think it does open up this like whole other universe. So what what do you think North Korea would use a small fleet of diesel submarines with, you know, short range navalized KN-23s to accomplish?

Joseph 16:50

Well, yeah, the other thing, the other kind of question we have. Apart from going, we also have an SLBM, suck it. There is that element that, you know. Which they basically said. Keeping up with the neighbors. Yeah, obviously this program has been in development for a while. It's not just suddenly developed because South Korea popped off a conventional SLBM from an SSB a couple of weeks before.

That might have prompted the test and publicity, but it did not prompt the program directly. Yeah, it's a tricky one. And one of the other things to mention is that, is this still capable? Because they didn't use the word strategic to describe the missile. They used the word strategic to describe a missile which the submarine has previously done, so the PK-1, but they didn't use the word strategic to refer to this new system, which makes me wonder if it's meant to be conventional.

Jeffrey 17:44

It does have that phrase about, which I think we also saw in reference to some of the other conventional submarines, like improving the underwater operational capabilities, which to me, it seems like a stock phrase that they're recycling. Although I don't quite know what it means, but it doesn't sound like nuclear deterrence, but I don't know.

Joseph 18:08

Yeah, I guess it's obviously, we know that from the Workers' Party Congress that, you know, tactical nuclear weapons, there's a clear intention there to develop those. We've seen them use, you know, the word strategic to refer to the cruise missile, which, you know, probably has a smaller payload capability. So I wouldn't rule it out, but obviously, you know, If we're looking at, are they switching between the strategic PK5 to potentially non-strategic, smaller system, that has a massive change in direction.

But yeah, I think what this new system could represent is, given the KM23 is relatively proven from their perspective compared to a lot of the other systems, it's probably one of the ones they've tested most in the last five years, to be honest. It still has a, well, the range is a little bit debatable, actually. They tested this system for 600K up until the rail launched KN-23, which we assume is a KN-23.

The previous one was, I think, 450. And then the rail launch in September, which we assume is a KN-23, was 800 kilometers. And that included the kind of pull-up maneuver. So, you know, this is actually quite a long-range system. And, you know, if you actually did it as a, Of a minimum energy trajectory, we are probably talking kind of over the threshold for medium range, over the thousand kilometer threshold. So you know, even when you look at where, you know, from Simpo, a 600 kilometer missile can target the vast majority of South Korea. 2000 kilometer range of say the SLBM, the PK5, it's still, you know, it still has enough to be of concern.

Jeffrey 19:48

Yeah. One question I have is how much advantage do you think the North Koreans see in, you know, the I mean, there's the downside of if you go out too far, right, that you're going to be more vulnerable to anti-submarine warfare. On the other hand, to the extent that you get out away from the coast, you have new areas.

Angles of attack that are now available to you, which would really stress South Korea's missile defenses. How do you see that balance playing out, whether it's from their perspective or just, you know, how you would work through it as a strategic thinker who sort of weighs trade-offs?

Joseph 20:28

Okay, yeah, I think it's a tricky one to say because, you know, North Korean submarine operations are a bit elusive, obviously, but they tend to stay very close to shores. Obviously we have historical exceptions when they've gone into South Korean waters, of course, they're well published, but these are, you know, even though they have essentially ocean-going submarines, particularly in the Romeo class, they don't use them as such.

I think there was an incident a few years ago where one went to a hundred kilometers off range, which is a hundred kilometers offshore. And that was rare and noteworthy. And that hasn't happened before since Valerie. So, you know, it just shows you how much use, how they concentrate in the littoral essentially in safe waters, you know, and there's lots of reasons behind that, you know, defections are a possibility that vulnerability is a possibility.

Jeffrey 21:16

The worst remake of Hunt for Red October ever. The Hunt for August 24th. Not even James Acton, who loves The Hunt for Red October, would sit through The Hunt for the Hero Submarine August 24th.

Joseph 21:35

Well, I think it was Steel Reign 2. Basically, the premise was going aboard the SSB.

Jeffrey 21:42

I don't, what is Steel Rain 2? I don't know this.

Joseph 21:44

I saw, I've seen, we're going above topic, but the Steel Rain, which was a South Korean film about, I think, a North Korean coup. They made a sequel, which is apparently the, at least the third act or the second act or something, or the climax is based upon them going aboard the SSB. So I haven't watched this.

It's not a recommendation, but-

Jeffrey 22:08

I think we have a mission now. We need to have an arms control wonk and friends of arms control wonk. Steel Reign 2, you said?

Joseph 22:23

Yes, I think so.

Jeffrey 22:24

Steel Reign 2 watch party. I'll bring the phone. Yeah, we can get some Korean beer and some kimchi and just sit down and I'll watch it, Mystery Science Theater 3000 level.

Joseph 22:43

Yeah, so sorry about the, so yeah, I don't think they're gonna go far from territorial waters or territorial waters. And particularly when we're talking about carrying arms missiles, potentially nuclear missiles, The command and control, the communications elements of that, basically a whole lot of unknowns. There's also, you know, they're just vulnerable because these aren't, you know, quiet, stealthy submarines.

You know, they are... Obviously, when they're running on electric power, which will be limited because they're not using modern technologies, they can do so and they can remain quiet. But, you know, at some point they have to snorkel, run their diesel engines. So, you know, putting them in the open water, which is a less challenging ASW environment for South Korea, Japan, US, they'd just be so vulnerable.

So you see this as fundamentally a littoral strike capability. Yeah, I do. It's basically just moving them offshore. Not far offshore, but moving them offshore. And that is, you know, irrespective, it is harder to target than a land-based system, even if it is road mobile or rail mobile.

Jeffrey 23:56

Is there anything... Is there anything... We haven't talked about anything big. You wanna, you, you want us to take away from this? Because I, I feel like, I feel like, I, I've ended this conversation with a much clearer sense of this program than I started with, and that makes me happy. one thing we didn't talk about is whether it was actually launched from a submarine. Oh my god, we didn't talk about that. So

Joseph 24:26

Well, North Korea said it was launched from the submarine. They showed us the submarine. They showed it with...

Jeffrey 24:32

They showed us a submarine.

Joseph 24:35

Yeah, they showed us what we know as the Goray, which is the only... What you know is the Goray.

Jeffrey 24:40

I apparently can't tell it from a rubber duck, but...

Joseph 24:43

Yeah, they showed us the submarine. They showed it, you know, apparently either partially way through submerging or... The little hatch is open? They showed us the hatch jar at the top, which implied at least that a missile had been used. And, you know, we've seen that before with previous tests, after the test. But they said that something was used before and it wasn't in previous tests.

It would also be relatively unusual for initial tests of an untested system to use A crude submarine and not a submerged barge. And, you know, it's particularly true because there was even reports that in one of the PK-1 tests, the submarine actually got damaged. So, you know, there was a risk to the submarine, particularly the new system.

Now, arguably, they say that they've tested the ejection system well enough and they know decay in 23 relatively well by this point. So there's no one to say, yes, they were taking the risk in this case. There's some kind of, I think, NK News, one of their reporters, got some imagery from Planet, which does indicate that in the days before the barge moved.

Certainly, I've looked at some Maxar imagery from today, and it's certainly back, and there's no canister visible. So it may imply that it may have been moved, but not so used. So yeah, I think it probably was used, but I think there's a note of caution regarding what Northgate show us.

Jeffrey 26:12

Yeah. That's sort of where I am that at some point they're going to make that, that shift if they haven't already. Right. And I mean, you got to do it. And there were reports that one of the tests damaged the sale. So, I mean, clearly the intention was, was to get there. So I don't know. I put that down and I put that down in the category of at some point they're going to shift over.

And, and I think I'd rather be too early than too late in making that prediction.

Joseph 26:38

Yeah. And that's, of course, if you want to be a bit more conspiratorial, we could talk about Japan's insistence that there was two launches.

Jeffrey 26:47

Oh, actually, we should talk about that because I find that very curious for some other open source reasons that puzzle us. So why do they what do you make of the fact that they are insistent that it was two launches?

Joseph 27:05

Yeah, it's an interesting question. So my only kind of most obvious thing is they saw two projectiles. So there's no suggestion that the KN-23 is two-stage, beyond the ejection at least. The other possibility is that it did do a pull-up maneuver. So they could have potentially had two, what appeared like two different projectiles at some point. And that may have confused some of the initial South Korean reporting around that as well.

The only other possibility is they did launch two projectiles, initially one from the sub, one from the barge, but that's probably reading into it a little bit much. But it is quite curious that the Japanese Prime Minister literally said there was two ballistic missile launchers. And rather inconveniently, that came on, it was literally announced on the radio as I was going on air and had to kind of dethrone me yesterday.

Jeffrey 28:01

Yeah, I think that in general, I just, I accept that radar systems are imperfect and that, you know, sometimes you see things that aren't there. And if you're the Russians, especially, you miss things that are. But it is, you know, it's a data point, I guess. So for now, I'm just going to accept that there was one, but I'm always going to be a little curious about it.

Joseph 28:23

Yeah, I think the consensus is certainly that there's one missile. And certainly that's what North Korea said. There may be a good reason why Japan is going on too. And some of that reason may become clear in coming days and weeks.

Jeffrey 28:39

Okay, I think now we really are truly done. Well, that was a fantastic conversation. If you like the Arms Control Wong podcast, you would have support us. You can go ahead and do so by going to patreon.com forward slash ACW podcast. You get access to our occasional mini pods and more importantly, the Slack channel, which is a great place to hang out, talk about this stuff.

And get quoted by reporters who do always ask for permission first. That is $5 a month if you are just a regular old person and only $3 a month if you are a student. Joe Dempsey, thanks for joining me. It's been a pleasure, Jeffrey.