A Solid Move Towards DPRK Second Strike Capability
The test of the Pukguksong-2 (PGS-2) was an expected, but major step for North Korea’s missile forces. The Pukguksong-2 is fairly similar to the Pukguksong-1 (PGS-1) and appears to be a land-based variant of the original PGS-1 missile. The PGS-2 represents the DPRK’s move or attempted move to a land-based solid-propellant missile force, which, if successful, will be more survivable and valuable as a coercive tool than a liquid-propellant dependent missile force.
The launch imagery released showed that the Pukguksong-2 (KN-11) missile is a medium-diameter solid-propellant system that is cold launched from a canister atop a tracked transporter erector launcher (TEL). Since it is still in the testing phase, these details could change.
This means the PGS-2 will likely have a launch prep time of between 15 and 45 minutes, as opposed to the hour or more an equivalently-sized liquid-propellant system may need. It will require no additional fuel trucks, reducing the number of moving vehicles and people that could tip off surveillance systems to an impending launch. It has a tracked TEL, giving it access to rougher terrain in the mountainous interior of the DPRK and increasing the possible locations that must be surveilled ahead of time. It also appears to be co-developed with a submarine-launched ballistic missile that will be difficult to track and preempt.
Imagery and Media Messaging
The DPRK is sending the message that it is moving towards a domestically-produced survivable second strike capability, something that would contribute towards a credible North Korean deterrent against its neighbors and opponents. KCNA and Rodong Sinmun both carried the following statement attributed to Kim Jong-un:
“Now our rocket industry has radically turned into high thrust solid fuel-powered engine from liquid fuel rocket engine and rapidly developed into a development- and creation-oriented industry, not just copying samples, he [Kim Jong-un] said, adding:
Thanks to the development of the new strategic weapon system, our People’s Army is capable of performing its strategic duties most accurately and rapidly in any space: under waters or on the land.”1
The pursuit of solid propellant mobile missiles is not unusual. China, Russia, and India all rely on solid propellant mobile missiles to ensure a strategic deterrent that is hard to track and fast to launch, increasing the survivability of their strategic missile systems and increasing the credibility of their respective deterrent forces. The PGS-2, especially when paired with the submarine-launched PGS-1, may mark the beginning of North Korea’s transition away from liquid propellant missiles, which are both slower to launch and easier to track than solid propellant systems.
If the DPRK bolsters the Strategic Missile Force with solid propellant intermediate-range ballistic missiles (IRBMs), medium-range ballistic missiles (MRBMs), and, eventually, intercontinental ballistic missiles (ICBMs), its neighbors could not reasonably rely on being able to destroy missile launch systems in the moments before they launch. This will instead either deter neighbors, forcing them to accept the DPRK’s position, balance with additional offensive systems, or push the onus of defense onto politically sensitive ballistic missile defense systems like Terminal High Altitude Air Defense (THAAD).
The PGS-2 and the submarine-based PGS-1 are laying the groundwork for a complex, multipolar deterrent founded on an emerging second strike capability as well as a long-range solid-propellant missile industry, two things that will likely be lasting problems for all regional actors.
The DPRK already has a large, formidable arsenal that arguably provides a deterrent against its neighbors even when primarily uilizing a liquid propellant force. The move to solids will increase the strength of its deterrent and greatly increase the difficulty in leveraging military force against North Korean missile systems in times of conflict.
Just like the Pukguksong-1 before it, it is clear from the relatively dirty plume that the Pukguksong-2 is a solid propellant missile, as opposed to the relatively clean plume produced by liquid-propellant systems. The DPRK is known to operate only two other solid propellant ballistic missile systems, the Pukguksong-1 and the KN-02 short-range ballistic missile. It also operates several smaller solid propellant multiple rocket launcher systems and surface-to-air missile systems.
Image: Comparison of the PGS-2 plume (left) and the Musudan’s plume (right).
Both photos by Rodong Sinmun. Left, February 13, 2017. Right, June 23, 2016.
Solid propellants are difficult to handle and manufacture, especially in larger sizes, but provide several strategic advantages to liquid propellants. Solid propellant missiles generally require fewer support vehicles and less time to prepare for launch, making it harder to track and preempt systems.
Liquid-propellant missiles like the DPRK’s Hwasong-5, Hwasong-6, Musudan, KN-08, and KN-14 are typically transported empty with fuel and oxidizer carried in support trucks, with few exceptions. The missile is fueled up on the pad, which is a time-consuming process that leaves the missile and crew vulnerable to detection and preemption. Even though liquid-propellant missiles are slow to load, they are still difficult to detect and preempt in time, with the U.S. and, more recently, Saudi Arabia failing to preempt Scud launches.
For comparison, Soviet Staff Academy writings indicate that early Scud missiles (the basis for North Korea’s Hwasong-5 and Hwasong-6 missile systems) required about an hour to fuel up, with additional time to prepare the rest of the system and fire.2 Later reports indicated that Iraqi Scud crews could prepare their systems in under a half an hour. 3 Launch preparation times for a DF-3, a Chinese legacy MRBM, are reported by various sources to be between 2 and 2.5 hours minimum, not including transit time to firing point.4
In contrast, variants of the OTR-21 Tochka solid-propellant short-range ballistic missile (the basis for the North Korean KN-02) can be moved and fired in around 16 minutes.5 Additionally, the Federation of American Scientists lists the DF-21 preparation time as being between 15 and 20 minutes.6 Solid propellant missiles are deployed with their fuel already loaded, significantly reducing both the preparation time needed and the number of additional support vehicles needed for launch. In the 1980s, CIA imagery reports compared the aforementioned DF-3 to the then-emerging DF-21 system. The DF-3 required approximately 30 ground support trucks, while the DF-21 would need around six vehicles, include its TEL.7
The transporter erector launcher (TEL) used in the test is the only tracked TEL used in any modern rocket force. The Soviet Union historically fielded several missiles which used similar tank-style chasses, such as the RT-15 and the very early Scud A, but they deprecated decades ago. Opting for a tracked chassis instead of a wheeled one will better leverage the DPRK’s rough terrain as a strategic asset instead of a logistical hindrance.
Mark Fitzpatrick and Michael Ellemen note that the KN-08 and KN-14 missile systems, both liquid propellant missiles on wheeled TELs, would likely be restricted to the few hundred kilometers of paved roads within the DPRK, reducing the amount of space that surveillance systems would have to monitor to catch KN-08/KN-14 launch preparations.8
If the PGS-2 is actually deployed on its tracked TEL, it will have greater access to the DPRK’s extensive network of unimproved and unpaved roads as well as off-road areas. A tracked TEL will generally move slower than a wheeled TEL, but the increase in usable area would be worth the tradeoff. A tracked TEL capable of accessing unimproved roads increases the search area for intelligence, surveillance, and reconnaissance (ISR) systems significantly, additionally complicating potential preemption.
Approaching A Complex Strategic Deterrent
The PGS-2 and its TEL are practically designed to avoid preemption and maximize survivability, like other modern mobile strategic missiles. These developments, paired with the PGS-1 submarine-launched ballistic missile and the already formidable liquid propellant arsenal, ultimately contribute to the achievement of a DPRK first and second strike capability. Difficult to destroy systems are good for preserving a second strike capability, allowing the DPRK to launch (or threaten to launch) without the risk of its missile force being a one-time use strategic capability.
The PGS-2 and the submarine-based PGS-1 are laying the groundwork for a complex, multipolar deterrent founded on an emerging second strike capability as well as a long-range solid-propellant missile industry, two things that will likely be lasting problems for all regional actors. The DPRK still has not shown off motors large enough for solid-propellant ICBMs or an industry robust enough to produce large numbers of solid rocket motors, but state media and imagery is sending the message that they are working towards both goals.
- “Kim Jong Un guides Test-fire of Surface-to-Surface Medium Long-range Ballistic Missile,” Rodong Sinmun, February 13, 2017. ↩
- Ghulam Dastagir Wardak, The Voroshilov Lectures Volume III: Issues of Operational Art (Washington, D.C.: National Defense University Press, 1992), 232-223. ↩
- William Rosenau, “Special Operations Forces and Elusive Enemy Ground Targets,” RAND, 2001, https://www.rand.org/content/dam/rand/pubs/monograph_reports/MR1408/MR1408.ch3.pdf. 32. ↩
- “DF-3A,” Federation of American Scientists, https://fas.org/nuke/guide/china/theater/df-3a.htm. ↩
- “Tochka-U high-precision tactical ballistic missile system,” Konstrucktorskoye Byuro Mashynostroyeniya, http://www.kbm.ru/en/production/otrk/351.html. ↩
- “DF-21/CSS-5,” Federation of American Scientists, https://fas.org/nuke/guide/china/theater/df-21.htm. ↩
- “New Mobile Solid-Propellant MRBM Under Development, China,” National Photographic Interpretation Center, November 1, 1983, https://www.cia.gov/library/readingroom/document/cia-rdp84t00171r000300410001-4. 8. (Declassified) ↩
- Mark Fitzpatrick and Michael Elleman, Pre-empting a North Korean ICBM Test, January, 9, 2017, http://www.iiss.org/en/politics%20and%20strategy/blogsections/2017-6dda/january-7f20/pre-empting-a-north-korean-icbm-test-ae68 ↩