North Korea’s November 28 Hwasong-15 ICBM Test: Big Missile and Big Advance

North Korea’s new Hwasong-15 ICBM is, to be blunt, a big fucker. I write here a brief preliminary analysis. On November 28 North Korea test launched the new ICBM on a highly lofted trajectory reaching an apogee of 4,475km and a range of 950km. The launch appears to have been prepared at the March 16 factory in Pyongsong province, based on excellent geolocation work by Jeffrey Lewis. This is where Kim Jong Un recently inspected a truck manufacturing facility. The Hwasong-15 is transported by a new 9 axel TEL.

If launched on an MET trajectory the Hwasong-15 would reach a range of more than 13,000km putting all of the continental United States within reach, and indeed much of the world bar South America, snippets of Africa and chunks of Antarctica.

The Hwasong-15 looks much like the Titan II ICBM/SLV. See the two images below.

Notice that the Hwasong-15 RV or shroud doesn’t look too dissimilar to the Titan II either, and is more typical of the bulkier KN-14 ICBM (old nomenclature, never tested just paraded) RV rather than the Hwasong-12 or Hwasong-14 RV/shroud. See below for Titan II RV and older KN-14 RV.

Earlier this year a spat, occasioned by a sloppy New York Times article, on the providence of North Korea’s UDMH propellant exercised analysts. The New York Times had claimed that the US didn’t employ UDMH, however the Titan II employed Aerozine-50 propellant which is a 50-50 mixture of hydrazine and UDMH. Aerozine-50 has a slighter higher specific impulse than UDMH alone. I’m not necessarily implying anything here, just making this potentially interesting point out.

David Wright in his initial analysis, linked above, stated of the payload/RV mass that

We do not know how heavy a payload this missile carried, but given the increase in range it seems likely that it carried a very light mock warhead. If true, that means it would be incapable of carrying a nuclear warhead to this long distance, since such a warhead would be much heavier

That contention appears to have been too hasty, doubtless based on an extrapolation of the Hwasong-14. A KCNA press release stated,

The ICBM Hwasong-15 type weaponry system is an intercontinental ballistic rocket tipped with super-large heavy warhead which is capable of striking the whole mainland of the U.S. This system has much greater advantages in its tactical and technological specifications and technical characteristics than Hwasong-14 whose test-fire was conducted in July last, and it is the most powerful ICBM which meets the goal of the completion of the rocket weaponry system development set by the DPRK

Close observers of my articles here would have noted that I have long argued that the hydrogen bomb that North Korea tested on September 3 was to be delivered by a new ICBM and that was argued for on three grounds (1) the North Koreans themselves told us this, (2) the March 18 revolution engine would not have given North Korea sufficient throw weight for all US hydrogen bomb targeting (3) the new ICBM would likely need a cluster of two March 18 revolution engines to provide the necessary thrust for comprehensive US hydrogen bomb targeting. The images below show what is reportedly a model of the boosted fission device and the hydrogen bomb tested in September

Initial acceleration analysis of the Hwasong-14 ICBM suggests a thrust of 40 to 45 tonnes. The early Chinese DF-5 ICBM engine, the YF20-A, for example, had a thrust of about 76 tonnes (the DF-5 employed more than one YF-20A). When North Korea statically tested the March 18 revolution engine a claim of 80 tonnes of thrust was made, but that would better describe a twin cluster performance.

North Korea has revealed that the Hwasong-15 has indeed a cluster of two, most likely March 18 revolution, engines. Images that I have seen suggest that the Hwasong-15 does not employ vernier engines for steering, rather the twin engines are gimballed which would represent a major advance for North Korea. See below for Hwasong 15 and Hwasong-14 plume comparison.

That would no doubt be what, partly, North Korea means when it states, in the above, that the Hwasong-15 has more advanced technical characteristics than the Hwasong-14. If North Korea has a more advanced missile control mechanism it may very well also have a more advanced guidance system, hence making for a more accurate missile. Missile guidance is largely a function of flight errors prior to separation of the RV in space. See images below for twin engine cluster on the Hwasong-15.

A more powerful ICBM giving Pyongyang comprehensive US targeting, which carries a payload with a much more powerful bomb than a boosted fission weapon based on the disco ball of death, and one which is more accurate is, from both a strategic and technical perspective, very much a big deal. Doubtless I will have occasion to reflect more deeply upon these aspects in due course.

The Hwasong-15 test has came after a relatively lengthy lull in North Korea’s missile testing programme, which, to me, suggests that North Korea is following its own mature scientific research and development timetable rather than testing for political effect following a Trump tweet, statement or display of air and maritime power.

The interesting thing about the potential gimballed nature of the Hwasong-15 first stage engines is that, firstly, they are not sunken. Hitherto it has been supposed that a North Korean twin engine cluster would consist of a pair of 4D10 engines, however the 4D10 is a sunken engine. The 4D10 even with a twin engine cluster would not give North Korea the thrust for an ICBM with a larger throw weight than the Hwasong-14.

Secondly, the RD-250/RD-251 configuration for the Soviet R-36 (SS-9) ICBM uses vernier engines. See below. However, it appears thus far, that the Hwasong-15 twin engine cluster is gimbaled which is different. That militates against the RD-250 providence of the March 18 revolution engine. That’s because the RD-250 is a twin chambered configuration sharing the one turbopump and when arrayed in a three twin chambered configuration, as with the R-36 ICBM, it is known as the RD-251. Assuming an RD-250 providence for the March 18 revolution engine the most rational road for North Korea to follow post Hwasong-14 would have been to simply use the original RD-250 twin chambered configuration with verniers for the Hwasong-15. See below for business end of R-36. Note the verniers.

I subscribe to the view that North Korea’s recent missile and nuclear advances are largely the result of indigenous efforts. The Hwasong-15 test launch appears to support this thesis.

South Korea immediately following North Korea’s Hwasong-15 ICBM test launched a missile of its own in a “missile strike drill” meant to demonstrate a capability to launch a preemptive strike against North Korea’s missiles. That provides strong incentive for North Korea to strike first in a crisis on the familiar use them or lose them dynamic.

As we know the Trump administration is conducting a review of US ballistic missile defence policy. It will be interesting to see what impact the Hwasong-14 and Hwasong-15 will have on that review. Take, for example, European BMD. Ballistic missile defence has had a controversial history, from SDI to George W Bush’s European GMD in Poland to Obama’s, the current policy, phased adaptive approach based on Aegis SM3 BMD both at sea and ashore. European BMD is sized against a threat that doesn’t exist, namely an Iranian ICBM. The Iranians have indicated that they would cap their missile programme to 2000km maximum range. However, any NATO involvement alongside the US on the Korean peninsula now opens up the prospect of North Korean thermonuclear strikes in Europe and old ideas regarding the transatlantic link might revive European GMD, which would be strongly opposed by Russia and so negatively impact upon strategic stability in Europe.

There is much more to be said as details further emerge and solidify, but I will leave my analysis here for now.

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