Mattis: “North Korea ICBM Not a Threat Right Now” Part 1

The North Korea ICBM threat is not visceral. With two brief exceptions, nuclear conflict has never been felt, but only imagined. Because it remains the subject of nightmarish contemplation, open source offers a meaningful fraction of the material chomped on by DoD and the White House. There is enough that we can imagine ourselves “in the room”, as flies-on-the-wall, as the U.S. response is debated at the highest levels. We begin with the technical in Part 1, and continue  in Part 2 with the political.

(CNN 12/16/17): Mattis says North Korea isn’t capable of striking the US. The CNN video sequence continues with statements by Tillerson and  McMaster. Quoting Mattis,

He added that the United States is still assessing the situation. "We are still examining the forensics, we're still doing the forensics analysis, it takes a while," he said.

A brief description of the forensics. The descending parts of the missile are tracked by radar at low angles relative to the horizon. This is challenging under the best conditions (imagine the haze you always see on the horizon).  Unless the tracking radar happens, by luck, to be near the splashdown point, it must cope with false reflections, atmospheric effects, and ionization.

As the descending parts pass through roughly 300,000 feet, they are enveloped in clouds of ionized, glowing gas, which reflect radar much more strongly than the objects themselves. This always happens, but is magnified if the parts have coatings  that vaporize – a complication.  It becomes difficult or impossible to know how large the objects actually are, and their individual identities frequently become lost. As they pass through 100,00 feet, the glowing cloud dissipates. Falling through dense atmosphere, how fast they fall provides estimates of how dense they are. But at this point, the smaller pieces are frequently lost. It may be impossible to distinguish between an upper rocket stage, and a reentry vehicle, and a fragment.

Air search radars and tracking radars do not provide visual images.  Radio echoes are interpreted by computer to provide user friendly displays. So where does the forensics come in?  Military radars have echo recorders. The U.S. maintains a large library of echo data from various targets. These are used for comparison, but an exact match is not the goal. So a paraphrase of Mattis’s statement could be, We think the business end of the missile fell as a bunch of junk, but we can’t be sure.”

Quoting again, we have an opinion about how useful the missile really is:

"I'm highly suspicious about the capability of the Hwasong-15," retired Gen. Patrick O'Reilly, a senior fellow at the Atlantic Council and expert in aerospace and missile defense, said in an email....The red flag for O'Reilly and other missile experts is that the North Koreans keep shooting the missile almost straight up, and not in the parabolic arc of a standard missile trajectory, which is harder to achieve.

O’Reilly is undeniably correct. Imagine throwing a baseball. There are three ways your throw can be off:

  • Velocity.  If you throw straight up, the strength of the throw doesn’t matter; it comes straight down. If you’re trying to hit a patch near the fence, the strength of the throw is half the problem. For an ICBM, this is equivalent to the thrust of the rocket motor, and the exact time of rocket motor cutoff. Both require extreme precision.
  • Vertical angle, (elevation). The straight upwards lob is easy. If you don’t throw it exactly straight up, the error coming down is mild, proportional.  But for a distance throw, the error is much more than proportional. For your ball to land on the patch near the fence, you have to coordinate the strength of your throw with a mentally calculated “keyhole” in mid-air. The ball must pass through the keyhole at the exact speed. This is a two-variable, mental calculation that some athletes can perform with astonishing accuracy.
  • Bearing, compass-point,  or “azimuth” At 6000 miles, a 1 degree error in bearing is 105 miles.

But a wildly inaccurate Hwasong-15 still has some chance at successful delivery of  a nuclear warhead to the vicinity of U.S. population centers. Avoiding re-entry difficulties, a high altitude nuclear detonation would comprise a successful EMP attack.

The above should not be taken as second-guessing Mattis’s statement, which fits the difficult requirement of single-sentence brevity. But we can use it as an opportunity to examine the context of decision making at the highest level. The decision makers are served by pyramids of specialists and their analyses.  But the vast mass of  detail doesn’t survive. it all distills down to:

  • A weapon of poor quality, but not proven to inevitably fail in all modes of use.
  • An adversary who, the intelligence community has concluded, satisfies at least some of the definitions of sanity, but not all of them. Kim Jong-un has an unremitting blood lust.
  • The assumption that the adversary is sane enough to lack confidence in his poor quality weapon, and to understand the consequences to him of use.
  • Clandestine factors. Hinted at, there is no point in guessing. They could provide a pleasant upside, but we are primarily interested in limiting the downside.
  • The risks of doing something.
  • The risks of doing nothing.
  • The domestic political climate.

The first three items result from foreign intelligence. They make an argument against immediate action that can be somewhat negated by reductio-ad-absurdum:

  • As the quality of the ICBM improves, the chance that the Kim Jong-un will use it increases.
  • The endpoint is a weapon that Kim Jong-un can use with confidence.
  • But then he faces massive retaliation. Hence, the quality of the missile is irrelevant.

If you’re in the room, your response might be, “Let’s move on.” In spite of attempts at rationality, only Harry Truman’s sign can deal with it. But you wanted to be in the picture, didn’t you?

To be continued shortly.

In the meantime, can our adversary’s demands be met?

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