The explanation for North Korea’s rapid progression in long-range missile technology is simple: it acquired a high-performance liquid-propellant engine from a foreign source.

North Korea’s missile programme has made astounding strides over the past two years. An arsenal that had been based on short- and medium-range missiles, along with an intermediate-range Musudan that repeatedly failed flight tests, has suddenly been supplemented by two new missiles: the intermediate-range Hwasong-12 and the intercontinental ballistic missile (ICBM) Hwasong-14. No other country has transitioned from a medium-range capability to an ICBM in such a short time. What explains this rapid progression? The answer is simple. North Korea acquired a high-performance liquid-propellant engine (LPE) from a foreign source.

Available evidence clearly indicates that the new LPE is derived from the Soviet RD-250 family of engines, and has been modified to operate as the boosting force for the Hwasong-12 and -14. An unknown number of these engines were probably acquired though illicit channels operating in Russia or Ukraine, or both. North Korea’s need for an alternative to the failing Musudan and the recent appearance of the modified RD-250 engine, along with other evidence, suggests the transfers occurred within the past two years.

Tests reveal recent technical gains
North Korea ground tested a large LPE in September 2016, which it claimed could generate 80 tonnes’ thrust. The same LPE was again ground tested in March 2017. This test included four smaller, steering engines. On 14 May 2017, with Kim Jong-un overseeing test preparations, North Korea launched a new intermediate-range ballistic missile, the Hwasong-12. The single-stage missile flew on a very steep trajectory, reaching a peak altitude of over 2,000 kilometres.1 If the Hwasong-12 had used a normal flight path, it would have travelled between 4,000 and 4,500km, placing the American territory of Guam, just 3,400km away, within range.

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Michael Elleman is IISS Senior Fellow for Missile Defence. An earlier version of this article appeared on the IISS Voices blog.

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Survival: Global Politics and Strategy

October–November 2017

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