How has North Korea managed to make such astounding progress with its long-range missile program over the last two years?
North Korea’s missile program 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 has acquired a high-performance liquid-propellant engine (LPE) from a foreign source.
Available evidence clearly indicates that the LPE is based on 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 and/or Ukraine. North Korea’s need for an alternative to the failing Musudan and the recent appearance of the RD-250 engine along with other evidence, suggests the transfers occurred within the past two years.
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 2,000km. If the Hwasong-12 had used a normal flight path, it would have travelled between 4,000 and 4,500km, placing Guam, just 3,400km away, within range.
The success of the Hwasong-12 flight in May gave North Korean engineers the confidence needed to pursue a more ambitious goal: the initial flight testing of a two-stage missile capable of reaching the continental United States. Less than two months after the Hwasong-12 test, the two-stage Hwasong-14 was launched on 4 July. A second Hwasong-14 was tested on 28 July. The Hwasong-14 launches flew on very steep flight paths, with the first shot reaching an apogee of 2,700km. The second test peaked at about 3,800km.
The origins of the new engine are difficult to determine with certainty. However, a process of elimination sharply narrows the possibilities.
There is no evidence to suggest that North Korea successfully designed and developed the LPE indigenously. Even if, after importing Scud and Nodong engines, North Korea had mastered the production of clones, which remains debatable, this does not mean that it could design, develop and manufacture a large LPE from scratch, especially one that uses higher-performance propellants and generates 40 tonnes’ thrust.
Claims that the LPE is a North Korean product would be more believable if the country’s experts had in the recent past developed and tested a series of smaller, less powerful engines, but there are no reports of such activities.
An exhaustive search of engines produced by other manufacturers in the former Soviet Union yields a couple of possibilities, all of which are associated with the Russian enterprise named after V. P. Glushko, now known as Energomash. The RD-217, RD-225 and RD-250 engine families use high-energy, storable-liquid propellants similar to those employed by engines tested by North Korea. Neither the RD-217 nor RD-225 have external features matching those of North Korea’s new engine. The RD-250 is the only match.
The RD-250 engine consists of a pair of combustion chambers fed by a single turbopump. Each chamber produces about 394k Newtons of thrust, or about 40 tonnes’ force, when relying on UDMH as the fuel, and N2O4 as the oxidiser. The RD-250’s nozzle also features a cooling tube and a compliance ring that resemble those found on the engines tested by North Korea. The small engine with its nozzle pointed upward and displayed in the foreground is not associated with the RD-250 engine.
Acquisition of the modified RD-250 engine enabled North Korea to bypass the failing Musudan development effort and begin work on creating an ICBM sooner than previously expected. The Hwasong-14, however, is not yet an operationally viable system.
It is not too late for the US and its allies, along with China and perhaps Russia, to negotiate an agreement that bans future missile testing, and effectively prevents North Korea from perfecting its capacity to terrorise America with nuclear weapons. But the window of opportunity will soon close, so diplomatic action must be taken immediately. Author wishes to thank to Mr.