In recent years, North Korea has continued to make significant progress with regard to the development of its ballistic missile capabilities. North Korea may now have as many as eight intercontinental ballistic missiles (ICBMs) that are capable of striking the continental United States as well as an array of advanced shorter-range ballistic missiles that appear to be capable of challenging ballistic missile defense systems deployed in South Korea.
Another important area of ballistic missile development in recent years has been North Korea’s continued pursuit of undersea ballistic missile capabilities. North Korea has unveiled several new variants of its Pukguksong-series of submarine-launched ballistic missiles (SLBMs) and is reportedly nearing completion of a new, dedicated ballistic missile submarine (SSB).
Ballistic Missile Submarines
North Korea currently operates only a single ballistic missile submarine (SSB). North Korea’s sole Gorae-class SSB was launched in March of 2014. The vessel is operated with a crew of 35 and is 66.75 meters long with a 6.7-meter-wide beam. The Gorae-class SSB utilizes diesel-electric propulsion and has a maximum speed of 10 knots, and is believed to be capable of firing a single North Korean Pukguksong-series of submarine-launched ballistic missile (SLBM). Even so, the Gorae-class SSB’s ability to operate as part of a survivable secondary-strike component of the DPRK’s nuclear deterrent is limited by its lack of an Air-Independent Propulsion (AIP) system. The lack of an AIP means that the Gorae-class SSB cannot remain submerged for more than a few days before needing to surface. As a result, while North Korea’s Gorae-class SSB has been used as a testing platform for SLBMs, it remains unclear if North Korea intends to deploy the Gorae-class SSB as an operational delivery platform for its undersea ballistic missiles.
Since at least late 2017, North Korea is believed to have been engaged in the construction of a new ballistic missile submarine. Around this time, the United States intelligence community detected submarine construction activity at North Korea’s Sinpo shipyard. The new SSB has been given the designation Sinpo-C by the U.S. intelligence community – which follows on from the IC’s designation of Sinpo-B for North Korea’s single Gorae-class SSB – and early estimates placed the new vessel’s displacement at roughly 2,000 tons with a beam measurement of 11 meters, which would make the new SSB one of the largest vessels ever to be built for the Korean People’s Navy (KPN).
As of August 2019, North Korea appeared to have made substantial progress on the construction of the Sinpo-C SSB. More recently, both U.S. and South Korean intelligence agencies have speculated that construction of the Sinpo-C has been completed, and that North Korea is now waiting for an opportune moment to officially unveil the completed vessel. Assessments of the Sinpo-C have also been updated, with the vessel now believed to be closer to 3,000 tons. Like the Gorae-class SSB, the Sinpo-C likely features diesel-electric propulsion. Unlike North Korea’s existing SSB, however, the Sinpo-C is believed to be capable of carrying three or four Pukguksong SLBMs and may also feature an AIP system. This would allow the Sinpo-C to operate as something much closer to a truly survivable second-strike delivery platform.
Submarine-Launched Ballistic Missiles
North Korea has to date unveiled five separate variants of its Pukguksong-series of submarine-launched ballistic missiles, some of which appear to have been adapted for use land-based missiles. North Korea’s first SLBM testing came in 2014 with static testing of the Pukguksong-1, and the missile was first successfully flight tested in 2016. Testing of the Pukguksong-2, a land-based variant of the Pukguksong-1, followed in 2017. The Pukguksong-3, a return to the series’ sea-based roots, was tested successfully in 2019 and is believed to have a maximum range of up to 2,000 km.
North Korea’s continued development of both ballistic missile submarines and submarine-launched ballistic missiles has several significant implications. Even as North Korea’s undersea capabilities are likely to remain relatively limited, the introduction of a North Korean nuclear dyad and the resulting diversification of the country’s nuclear weapons will result in an overall more survivable nuclear arsenal. In addition, North Korea is believed to be focused on developing ballistic missile capabilities that are capable of challenging ballistic missile defenses in South Korea, and the use of SLBMs could support this goal by circumventing ballistic missile defenses that are focused primarily on land-based ballistic missile threats.
Finally, North Korea’s continued development of more advanced solid-fueled engines utilized by its SLBMs could lead to the production of solid-fueled ICBMs, which would represent a substantial increase in the DPRK’s ability to threaten the continental United States.