North Korea’s Weapons

By George Friedman

Recent weeks have seen the North Koreans launching missiles from submarines and, this weekend, testing another nuclear device, apparently the largest one they have tested to date. There are two questions to be answered. First, how significant are these tests militarily? Second, what are North Korea’s political intentions in launching the tests? The military capability comes before the political intention, since capability defines what is possible. The tendency of analysts to reverse the order has always puzzled me, save that understanding the capability is harder than speculating on political intent.

We know that the North Koreans have acquired both land-based and submarine-based missiles. The range of the former appears to include all of the Korean Peninsula and Japan. The range of the latter is uncertain. The range matters of course because it determines the targets that are at risk. Since the North Koreans have launched a satellite, at least some of the missiles must be robust enough to reach escape velocity and the satellite must be orbiting something. They have reached the threshold of launching an intercontinental ballistic missile, but have not clearly gone beyond that level.

We do not know very much about a critical element: the guidance system. Some rockets, like the Scud, have no guidance system. You fire the rocket and wait to find out where it lands. Advanced nuclear countries have superb guidance systems that allow missiles to strike within meters of the target. The difference between a rocket and a missile is that the latter has a guidance system. This is needed to attack missile silos that are extremely protected against a blast.

In between, there is a range of capabilities, partly inherent in the type of guidance system, partly dependent on the defects that are randomly present. At the moment, there is no evidence the North Koreans have missiles with an advanced guidance system, and many of the launches have revealed defects. That is pretty much what you would expect at this stage of missile development. The missile flies, the range is limited and the guidance system is a surprise party.

It is now clear that they have reached a reasonably high success rate in detonating nuclear devices. We do not know how many intended detonations failed, so we don’t know whether the success rate is rising, but it is reasonable to assume that it is. The difference between a nuclear device and a nuclear weapon is that the former is an undeliverable system, nested in a framework designed to maximize the chance of detonation. A bomb, on the other hand, can destroy a city.

The distance between a device and a bomb is substantial. A bomb must be small enough so that it can be fitted into a delivery system. It must also be robust enough to be placed in the delivery system without breaking. A device is not usually robust, and therefore nuclear weapons have to have a completely different framework than a device.

Building that framework is in some ways more difficult than building the device. There are two challenges. One is size, and the other is ruggedization. A nuclear device is a precision instrument. It must begin by triggering an explosion so precise in energy and shape that it will trigger either a fission or fusion explosion. The tolerances are extraordinary. When a nuclear device is turned into a weapon, it must be miniaturized in order to fit on a rocket or an aircraft. A nuclear device has no such constraints. Miniaturization of anything that is only being tested in a static environment requires not only superb engineering, but extreme craftsmanship and quality assurance.

The same is true with ruggedization. Precision instruments require care. A nuclear weapon that is properly miniaturized must be able to go through high G-forces on a rocket, along with vibration, enter a vacuum where extreme temperature swings occur every few seconds, and then re-enter the atmosphere at high or extremely high temperatures, depending on distances and angles of re-entry.

It then has to detonate. The platforms that are being used, apparently missiles, must also go through the same precise engineering, or it can fail on launch or in delivery. Bear in mind that the United States, with the most advanced missile technology, still experiences periodic failures and early in its program in the 1950s, its missiles were constantly failing. In developing any technology, the early versions will fail, not because the developers are unsophisticated or sloppy, but because they haven’t had the experience to eliminate all of the shortfalls.

North Korea appears to have reached the point that its missiles seem to launch without failures. That is only because there have not been sufficient launches to determine the failure rate – and every country has a failure rate on missiles or weapons in general. It seems to have attained an acceptable level, but that level is only meaningful in relation to the number of warheads it has. The fewer warheads you have, the greater the consequence of a failure. With a couple of warheads and a handful of missiles, you can’t craft a strategy. You can’t model the probability of success. It is a crapshoot.

As for the warhead, there is no evidence of development beyond the least sophisticated aspect of nuclear weapons – testing a device not capable of mounting on a platform. Given that the first trials were intended to demonstrate basic capability, that they have had five successful launches and an unknown number of failures, and that the size of the detonations is increasing, it seems that the North Koreans have not left the device stage. They are trying to increase the output and my guess (here, I think I’m right) is that they have not moved on to testing miniaturized and ruggedized warheads. They appear to be going for size, and that seems designed to impress observers – a politically useful strategy.

From my point of view, their missiles have not yet been tested sufficiently to determine failure rates, so they are very early in the program. We do not know their range and guidance system, which we would know from observing their performance and monitoring telemetry. They do not have a nuclear weapon and appear for now to be carrying out baseline explosions for political reasons, because they are having difficulty stabilizing the platform and yield, or because they do not have the technology to do more. However, five detonations under highly controlled circumstances is only enough information to conclude that they are very early in the game.

The political value of this is clear. North Korea’s primary interest is regime survival and they fear outside destabilization. The probability of having nuclear weapons is low, but it is not zero. Countries seeking regime change in North Korea have to take into account the low but real possibility of an effective nuclear strike. They will back away from that risk because North Korea’s internal affairs mean relatively little to them. In that context, its nuclear program is understandable. It deters external forces now, and develops, however slowly, the possibility of a real capability at some point.

In the meantime, being able to rivet the world’s attention and pretend that North Korea is significant is well worth the cost for the North Koreans. But they have a lot of work left to develop a nuclear weapon that not only works, but works consistently with a weapons platform that is likely to deliver it to a specific target. And since North Korea might at some point be able to deliver a device, but will not be able to deliver it at the level required to make it effective, the likelihood that it will launch a nuclear war is equal to the likelihood that another country will try to destabilize it.

We have a stalemate, and that’s what North Korea wants. And frankly, most other countries, including South Korea, want the same thing.