On May 9, 2015, North Korea’s state-run media, KCNA, aired a series of still images of a ballistic missile bursting through the ocean’s surface and igniting its main engine, all under the attentive eyes of Kim Jong Un. The authenticity of the images initially released by KCNA is unknown, as is the date of the test. The precise nature of the test is still unclear, as is the type of missile used. What is clear, however, is that a video summarizing the test produced and posted on North Korea’s propaganda website, Uriminzokkiri, included inauthentic footage of a missile launched from underwater in an attempt to exaggerate Pyongyang’s progress in developing a sea-based capability. The footage shows a solid-propellant missile being ejected from a submarine-launch tube, breaking through the sea surface and accelerating upward. The “missile” captured in the still photos of the North Korean test clearly depict a liquid-propellant engine. Photo analysis by Dave Schmerler highlights the sloppy editing job by the North Koreas, and the similarities to a known US underwater launch, most likely of a dated Trident missile launch.
Despite the doctored video, the test captured by still photographs indicates Pyongyang’s determination to create additional capacity—real or imaginary—to threaten its regional rivals, US interests in Asia and possibly the US mainland with ballistic missiles armed with nuclear weapons. In the regional context, submarine-launched ballistic missiles (SLBMs) offer North Korea a deployment option that is less vulnerable to preemptive strikes. Perhaps of greater importance, SLBMs can be fired from positions north, east, south and west of Japan, South Korea, Guam and other East Asian countries, a capability that greatly complicates missile defense planning and, if realized, could compromise defenses across the region. From a global perspective, an operational fleet of submarines armed with ballistic missiles, if developed successfully, could extend North Korea’s strategic reach, a capacity Pyongyang might view as a viable alternative to the difficult task of developing an arsenal of operational intercontinental ballistic missiles (ICBMs).
Testing at Sea
The missile appearing the still photographs released by KCNA is named “Bukgeungsong-1,” as indicated by the Korean characters on the airframe. Ironically, the name translates to “Polar Star” or “Polaris,” the latter parroting the name of the US Navy’s first-generation SLBM, initially deployed in the early-1960s. The Bukgeungsong-1 has a diameter-to-length ratio similar to that of the Soviet R-27 (4K10; SS-N-6), a sea-launched ballistic missile first deployed during the 1960s. The R-27 has a maximum range of about 2400 kilometers when delivering a 650-kilogram warhead. Persistent rumors suggest that R-27 missiles, or key components, were transferred to North Korea from Russian sources in the early- to mid-2000s, though direct evidence is sketchy. The rumors also allege that 18 or 19 R-27 kits were delivered to Iran. Steering engines similar to those found on the R-27 have appeared on the Iranian Safir satellite-carrier rocket, and the uppermost stage of North Korea’s Unha-2/-3 satellite launch vehicle may also be powered by similar steering engines. Mock-ups of a modified R-27—commonly referred to as the Musudan intermediate-range ballistic missile (IRBM)—have been featured during military parades in Pyongyang for several years. However, neither North Korea nor Iran has, to date, flight-tested the missile or one resembling the R-27. It remains unclear if the transfers took place.
Nonetheless, the geometry of the missile tested by North Korea is consistent with the R-27. One, therefore, cannot dismiss the possibility that North Korea acquired at least a few prototypes of the R-27 SLBM, if not a few dozen operational missiles. Yet, it is important to note that the recently tested missile did not include a few key features prominently visible on the Soviet version of the R-27, such as the instrumentation raceway and the apparatus that links the separable warhead to the missile’s main body. Further, the absolute length and diameter cannot be determined with confidence, a fact that prevents confirmation that the tested missile is based on the R-27.
It is difficult to determine the success of the limited test from a series of photographs, though some preliminary conclusions can be derived. Firstly, the missile was ejected from the launch tube at a slight angle, not vertically. This was likely done to mimic the launch angle required when firing operational missiles that contain a full-propellant load. Indeed, the US and others launch SLBMs at an angle to ensure that if the missile’s main engine fails to ignite, the weapon loaded with volatile propellant does not fall back onto the submarine and explode. North Korea appears to have incorporated the safety protocol into its development efforts.
Secondly, the missile’s liquid-propellant engine successfully ignited, demonstrating that the sequence and timing of events was nominally correct. It is not known how long the engine worked, or whether the missile flew a short distance on the desired path. Reports suggest the engine operated for only a few seconds, and the missile traveled only a few hundreds of meters. The abridged flight time is consistent with the apparent test objectives.
Additionally, this feasibility test would have used an engineering mock-up of the missile to be developed. The use of a mock-up is consistent with the absence of key external features mentioned previously. Moreover, employing a mock-up rather than a complete missile suggests that the test objectives were limited to evaluating the mechanism responsible for ejecting the missile from an underwater-launch tube, safely activating the missile’s propulsion system and stabilizing the missile as it accelerates upward.
Mock-ups can be manufactured cheaply and quickly, and can be altered easily to accommodate engineering modifications for future tests. And, safety concerns dictate that a “missile” containing little or no rocket propellant be used for tests aimed at evaluating launch-tube ejection mechanisms. For these reasons and others, North Korean engineers likely fabricated a mock-up missile that contained a small amount of fuel and oxidizer, perhaps one or two hundred kilograms, and a rocket engine for assessing the ignition and initial flight stabilization process for this feasibility demonstration experiment.
What missile engine was used for the test?
The presumed SLBM mock-up used for the launch-tube ejection test was powered, albeit briefly, by a liquid-propellant engine, but key details about the system remain unclear. The exhaust plume’s characteristics, most notably its color, suggest that the propellant combination used in the test was inconsistent with that employed by the Soviet version of the R-27. Rather, the engine used in the test produced a plume resembling those generated by North Korea’s Scud and Nodong missiles.
If Pyongyang’s SLBM under development is not powered by the R-27 engine and its propellant combination, the strategic implications are considerable. The Soviet R-27 has a maximum range of roughly 2400 kilometers, and its follow-on, the R-27U, can fly about 3000 kilometers. A North Korean SLBM having the same dimensions of the R-27, but using a Nodong engine, would have a maximum range below 1600 kilometers. That decreased maximum-range potential translates into substantially reduced patrol area for the submarine, which increases the risk of detection by North Korea’s adversaries.
Was the missile ejected from a submarine or an underwater launch tube affixed to a barge or fixed structure?
Photographs released by KCNA imply that the test was performed using a submarine. However, an analysis by Joseph S. Bermudez suggests that North Korea used a modified barge equipped with a submarine-launch tube replica. Such a configuration would be a reasonable substitute for preliminary experiments with limited test objectives, and it would create fewer variables for North Korea to consider when evaluating the test data. For example, the ability of the submarine to rotate along its longitudinal axis by a few degrees to provide the initial launch angle needed to direct the missile away from the submarine can be eliminated from the equation. A barge equipped with a launch tube tilted at a small angle is much simpler to implement. It is also easier to instrument an isolated launch tube, thus streamlining the acquisition of key performance data. More importantly, perhaps, employing a barge would have eliminated any chance of damaging a highly valued submarine during initial tests, when the risk of failure is the greatest. Lastly, employing a mock-up launch system would provide much of the same key data as a launch from a submarine.
It would be unwise to dismiss the North Korean test as a fraud or deception on the basis that it may have incorporated simulated articles and systems. Such tests can be reasonable and sensible; indeed, the Soviet Union employed similarly-equipped barges during initial SLBM development testing.
What are the next steps in the SLBM development process?
North Korea will likely conduct additional tests using a modified barge to validate the performance and reliability of the ejection process under a variety of operational conditions. Experiments using a submarine might then follow. Before firing an SLBM from a submarine, engineers would very likely conduct a few flight tests from a land-based launch complex to verify missile-performance parameters.
Other nations have required up to a decade to develop an operational SLBM, but North Korea has demonstrated a willingness to deploy strategic systems, including ballistic missiles, without completing a flight-trial program to validate the capability. Pyongyang may decide to accept the risk of failure and operationalize its unproven SLBM fleet within a few years.
Of key interest and importance is the fact that Pyongyang is testing and developing a new capability, one that if fully developed, would pose a threat to countries throughout Northeast Asia, most notably South Korea and Japan. Guam and Okinawa would also be threatened. And while sea-based launch platforms would diversify North Korea’s operational capabilities and provide a hedge against preemptive strikes on its land-based missile forces, the greater strategic consequence of SLBM development is the impact it has on ballistic missile defenses in the region. Land-based missile defense systems in Japan, South Korea, and Guam are aligned to counter threat missiles launched from North Korean soil. Sea-based missiles could be launched from positions behind missile defenses, where they would be more difficult—if not impossible—to detect, track and intercept.
The US and its regional allies and partners must monitor North Korean development activities closely and develop contingency plans accordingly. Aegis ships equipped with SPY-1D radars, which can scan in all directions to detect and track threat missiles, and SM-3 interceptors would partially offset the impact of North Korea’s sea-based missiles. Nonetheless, land-based missile defenses in the Asia Pacific region will require significant reconfiguration if the sea-borne threat posed by North Korea materializes.
Fortunately, a number of technological and operational barriers remain before Pyongyang can begin deploying a reliable SLBM arsenal. North Korea must perfect the ejection system, incorporate the equipment into a submarine, validate the performance of the missile under a variety of operational conditions, demonstrate that the missile is at least remotely accurate and reliable after being deployed in a launch tube for extended periods (possibly beyond 30 days) and establish the seaworthiness of its submarine fleet. Additional submarines must be manufactured if North Korea wants to deploy its SLBMs continuously. The country would require at least two or three submarines to maintain readiness over many years of operation. Construction at North Korea’s Sinpo shipyard may be for that purpose, though the site could likely fabricate only one submarine per year.
Additionally, Pyongyang must develop concepts of operations, create systems for communicating securely with the submarine when it is deployed at sea and perhaps most importantly, the leadership must institute the necessary command-and-control mechanisms. The latter necessity will require the regime to entrust a handful of nuclear weapons to a naval commander hundreds of kilometers from Pyongyang and Kim Jong Un himself. For a dictatorial regime seeking near-complete control over all elements of its security apparatus, delegating that nuclear authority may be a step too far. Still, one should not assume that such concerns would prevent North Korea from exercising an SLBM option.
Based on the experience of other nations, developing an operational SLBM requires three to ten years. But it is important to keep in mind that North Korea has demonstrated a willingness to deploy strategic systems, including ballistic missiles, without completing a flight-trial program to validate the capability. The Nodong missile, for example, was deployed after a single flight test. The Musudan IRBM and KN-08 ICBM have been paraded, and possibly distributed to military units without any known test launches. Judging from the success rate of first-generation missiles and satellite-launch vehicles during initial flight testing, the Musudan and KN-08 would fail more often than not if fired without adequate performance trials. Nonetheless, Pyongyang may decide to accept the risk of failure and operationalize its unproven SLBM fleet within a few years. The US and its regional allies and partners must monitor North Korean development activities closely and develop contingency plans accordingly.
 A fully-fuelled test article unnecessarily exposes personnel and equipment to injury or destruction if something goes wrong.
 For an excellent history of Soviet SLBM programs, see А.В.Карпенко, Н.И.Шумков «Морские комплексы с баллистическими ракетами», СПб. – Москва, 2009 г. (in Russian).
 It is unclear how many SLBM-related tests North Korea has performed to date. Some reports suggest this may have been the second or third “ejection test” of a missile from a launch tube. While the number of tests may provide a measure of how far North Korea has progressed in its development process, the figure is of only minor relevance.
 The Nodong missile, for example, was deployed after a single flight test. The Musudan IRBM and KN-08 ICBM have been paraded, and possibly distributed to military units without any known test launches. Judging from the success rate of first-generation missiles and satellite launch vehicles during initial flight testing, the Musudan and KN-08 would fail more often than not if fired without adequate performance trials.