How to Demolish the North Korean Submarine Missile Threat

Preemptive strikes and missile defense won't be enough to stop North Korea's new submarine-launched missiles.

The recent reported test of North Korea’s KN-11, dubbed Pukgeukseong-1 (Polaris-1) submarine-launched ballistic missile (SLBM) has created quite a buzz. In fact, not long before the test took place, the South Korean defense ministry remarked that there were no signs that Pyongyang would launch missiles in the near future despite the visit by North Korean leader Kim Jong-Un to the country’s satellite command and control center, operated by the National Aerospace Development Administration.

Washington took the recent development seriously, accusing Pyongyang of contravening existing United Nations Security Council resolutions by staging the test. South Korean government authorities sought to downplay the test, pointing out that it was no more than an ejector test and the missile was assumed to have flown only 100 meters upon lift-off. This appears to correspond with the subsequent assessment reached by the U.S. intelligence community, that a compressed-gas ejection system test was conducted instead of a launch from a submarine.

The Indians, for instance, tested their SLBM from an underwater pontoon numerous times before being confident enough to begin preparations to test it from their latest nuclear submarine, INS Arihant. It is therefore, plausibly to say, simply a matter of time before Pyongyang finally tests the SLBM from a submarine. Notwithstanding the actual status of the SLBM, it is clear that North Korea is in the process of developing such a capability. Seoul has since called Pyongyang’s SLBM development, believed to still be in early stages, a “serious challenge.”

Indeed, the focus on North Korea’s ballistic missile activities has always been terrestrially-bounded—from the static Rodong missile silos to the newer, more survivable mobile launchers. As was recently pointed out on The National Interest, by conducting the SLBM test, Pyongyang has demonstrated that it is on the way to a second-strike capability. That the test took place at sea, and not on land as it has always been the case in the past, certainly took the world by surprise.

Scarce information has transpired from the SLBM test, besides the latest assessments. What we do know is that there were earlier reports of a shore-based ejector-launch test. There were also grainy satellite pictures of a hitherto unknown type of submarine measuring an estimated 65.5 meters, likely a diesel-electric powered ballistic missile submarine (SSB in short), which was later dubbed the Sinpo class. Previous rhetoric from Pyongyang offered hints into more ambitious endeavours for its missile buildup, including talk about building a “more elite” nuclear deterrent.

As enigmatically it may sound, by now it should be clear that what North Korea means by a “more elite” nuclear deterrent is one that includes a sea-based element. This sea-based deterrent certainly adds to the shroud of ambiguity that Pyongyang often thrives on to make its intent and moves appear uncertain, thereby compelling its perceived adversaries to react with caution.

Some commentators forecasted a chain series of events that will plausibly heighten tensions on the Korean Peninsula, for example driving Seoul to expedite missile defense plans (including the controversial proposal to install the Theater High-Altitude Air Defense system, a move which has been roundly opposed by China, North Korea and Russia), as well as incentivizing its option of pre-emptive strikes against Pyongyang’s nuclear and missile arsenals.

However, it had also been pointed out that the North Korean SLBM, if deployed effectively, may nullify the utility of pre-emptive strikes, because SLBM launchers are more difficult to target. This is true. Compared to its land and air-based counterparts, the sea-based deterrent is undeniably more secure. Ballistic missile submarines are traditionally known to be some of the quietest: hard to detect and destroy.

In particular, nuclear-powered ballistic missile submarines (SSBNs) can roam the world’s oceans by exploiting its infinite power and underwater endurance, thus presenting ASW difficulties. With SLBMs of intercontinental-range, the SSBN can easily strike deep into enemy homeland from an appreciable long standoff distance, beyond the adversary’s anti-submarine warfare (ASW) coverage.

It is therefore a race for time. Before the SSBN can reach its pre-designated launch point to lob its payload at the target, the adversary’s ASW forces have to swiftly locate and destroy the boat. Only nuclear-powered attack submarines (SSNs) backed by long-range aerial and surface ASW forces can possibly counter such a threat. However, not every navy has the luxury of such a highly-demanding set of forces at its disposal.