This undated picture released from North Korea's official Korean Central News Agency on June 16, 2014, shows North Korean leader Kim Jong Un inspecting the submarine No 748 at an undisclosed location in North Korea. Photo: AFP / KCNA via KNS

SEOUL – The de facto missile race accelerating on both sides of the Korean peninsula’s Demilitarized Zone (DMZ) is expanding in multiple directions.

With both Koreas upgrading their tech and their teeth, the parameters of the race are diversifying from land-based launch systems to near space and under the waves.

On Thursday, South Korea launched a rocket whose launch vehicle provides the basis of an intermediate-range ballistic missile. North and South Korea have both recently tested submarine-launched ballistic missiles, or SLBMs. 

North Korea’s test of a “new type” SLBM on October 15 prompted a meeting of the UN Security Council.

On the face of it, North Korea’s missile boats – “boomers” in US naval parlance – represent stealthy, survivable, roving assets that could feasibly add range and mount nuclear weapons to deter the US.

Typically, opacity hangs over actual North Korean capabilities. For example, it has not been confirmed whether North Korea’s SLBMs were fired from an actual submarine, or from an underwater barge. Claims in state media, as ever, need to be taken with large grains of salt.

“North Korea appears to have tested a new mini-SLBM, but its propaganda about military capabilities should not be taken at face value,” said Leif-Eric Easley, associate professor of international studies at Ewha Womans University in Seoul. 

“Further analysis is needed to avoid underestimating or exaggerating Pyongyang’s ability to launch missiles from a submarine, miniaturize warheads and accurately guide them to a target.”

Some pundits comfort themselves in the belief that North Korea’s navy is an enfeebled resource. Even so, their addition to Kim Jong Un’s naval-strategic threat matrix presents yet another challenge for defense planners in off-peninsula locations such as Japan, Guam, Hawaii and even the continental United States.

But in a duo of ironies, tactical and strategic, ownership and deployment of these weapons represent a risk for North Korea, too.

Tactically, while a submarine is by nature stealthy and survivable, experts tell Asia Times that the threat represented by a potentially nuclear-armed North Korean boomer elevates it to a top-tier target.

And strategically, they represent a risk to the North Korean state that created them. The very existence of this “second strike” capability could, in times of tension, trigger a pre-emptive strike by a jittery US or even Japan, analysts say.

Kim’s underwater warriors

While there have been years of skepticism about North Korean rocket and nuclear capabilities, that skepticism has necessarily evaporated as Pyongyang pressed onward, successfully testing missiles with ever-longer ranges and nuclear devices with ever-greater kilo-tonnages.

Though North Korea has invested the bulk of its hardware resources in missiles and fissile materials, it has extensive experience with submarines and a large fleet of undersea assets. For a country that aims to punch above its weight, it is an asset class that makes doctrinal sense.

Due to decades of economic decline, North Korea has lost the ability to keep its massive armed forces fully equipped – or even fully fed. Triaging defense spend, Pyongyang, paranoid about US aggression, has focused on assets that offer maximum threat value: nuclear and missile programs and elite/special forces units.

With state founder Kim Il Sung having fought as an anti-Japanese guerilla and subsequently serving as a reconnaissance major in the USSR’s Red Army, North Korean forces have doctrinally favored asymmetric warfare.

In the naval space, this finds substance in commando-manned submersible powerboats and a wide range of submarines.

Just as the Korean People’s Army is believed to field the world’s largest special forces units – some 200,000 men, both Tier-1 special operations troops and Tier 2 light infantry units – the Korea Peoples’ Navy is believed to field one of the world’s largest submarine fleets.

Estimates range from 64 to 86 boats, according to security research group Nuclear Threat Initiative. The assets are operated both by the KPN – which mans the conventional boats – and the Reconnaissance General Bureau, which overseas espionage assets, such as mini-submarines.

A North Korean infiltration submarine captured in 1996, stands in stark contrast to the bunker in the background – an active duty east coast fortification manned by South Korean troops. Photo: Andrew Salmon/Asia Times

While this fleet is likely affected by the general decrepitude affecting North Korean forces and fuel shortages which limit training, it remains credibly dangerous.

“North Korean submarine technology is crude, but their submarines are aggressively employed and have proven to be a credible threat,” writes HI Sutton, a writer for naval publications who specializes in submarines and naval special forces.

In 1996, a “Sango” (“Shark”) class coastal submarine ran aground off South Korea’s northeast coast. The crew abandoned ship. Ashore, many were apparently killed by the amphibious commandos on board, who then sought to escape back to North Korea, prompting a weeks-long manhunt by South Korean troops.

In 1998, a similar vessel in a nearby locality became entangled in fishing nets. When it was hauled to the surface, its crew was found dead by suicide. Both captured boats are now on display in South Korea.

In 2010, the Cheonan, a South Korean corvette, sank with the loss of 46 lives in the Yellow Sea close to North Korea. Seoul insisted that the vessel was sunk by a torpedo fired by a North Korean mini-submarine in an unprovoked attack. North Korea denies responsibility.

Since these operations, North Korea has been working up a far more strategic asset: missile-carrying boats.

South Korean relatives visit a mourning altar at a naval base in Pyeongtaek in 2010 as they pay tribute to sailors killed in the sinking of the warship Cheonan, near the disputed border with North Korea. Photo: AFP / Korea pool

Suicide mission?

North Korea’s largest missile-armed submarine is believed to be the experimental “Gorae” (“Whale”) class boat, a diesel-electric vessel based on Russian designs.

Information is scant – it is not known if this week’s launch took place from this boat, from a moored underwater platform or from a converted, Chinese “Romeo” class boat, of which North Korea possesses some 20. Still, analysts have pieced together a jigsaw of data to map out capabilities.

A Gorae-class submarine can operate on electric engines for a maximum of five days submerged, during which it is “quiet, stealthy and to all intents and purposes, silent,” a person familiar with naval operations told Asia Times.

To operate with low noise underwater, its speed cannot exceed five knots (5.7 miles per hour), the source said. That means over the course of five days of 24-hour, underwater cruising, the boat would only cover 684 miles. 

After that time, it needs to resurface – almost certainly at night – to recharge batteries. During those (approximate) eight hours, the boat is vulnerable to identification and attack.

The distance between the Korean peninsula and the US coast is 6,690 miles. Given limitations on the amount of fuel and rations that can be carried, the patrol duration of a “Gorae” class boat maxes out at 30 days, the source said.

Half of that, naturally, must be spent on the homeward voyage. Or must it? Could, the North’s leadership extend that range past the point of no return?

Japan deployed kamikaze submarines during World War II, and experience from the 1990s proves that North Korean crews are willing to die for their mission. This raises the question of whether Pyongyang, in dire straits, might deploy the boat on a one-way mission, doubling its range.

But even then, a Gorae would only be able to cross 4000-4,500 miles of ocean.

The range of North Korea’s SLBMs is unknown, but is certainly shorter than its gargantuan land-launched ICBMs. The missile tested this week appears to be smaller than that of North Korea’s prior SLBM test, in 2019.

In both tests, the missiles reportedly flew around 450kms, though some experts suggest the earlier missile’s range could extend out to 1000 kilometers. The smaller size of the recent missile suggests more could be mounted in one vessel.

In sum, the estimated patrol and missile ranges look insufficient to reach the continental US. But US Pacific territories lie within reach.

“I am cautious to suggest that it will be conducting deterrence patrols off the US West Coast any time soon, but it does represent a launch platform which is not restricted to Korea’s landmass,” was the assessment of submarine expert Sutton. “Regional targets such as Japan, Guam and even Hawaii get a bit closer.”

In addition to stealth, range and firepower, another key submarine patrol metric is survivability.

A South Korean Navy team prepares to move a North Korean mini-submarine which ran aground in September 1996. Photo: AFP

Underwater gauntlet

Any North Korean missile-armed boat is likely to be under intense satellite and electronic surveillance at/around its east coat base. “There are ways to keep any eye on this kind of gear from very far away,” the naval source confided.

To break into the open Pacific, it would have to evade South Korea’s anti-submarine assets, which include a force of 50 UK and US-built anti-submarine helicopters. “Since the sinking of the Cheonan, the South Koreans have taken anti-submarine warfare very, very seriously,” said the source.

Those helicopters are necessarily divided between the peninsula’s east and west coasts, but for the North Korean boat, any Southern patrol cordon would be merely the beginning of a long, dangerous gauntlet.

Beyond the Korean littoral, the US Navy maintains major assets in the Western Pacific. Moreover, Japan’s Maritime Self Defense Force is considered to be a highly capable submarine-hunting force.

Yet in the cat-and-mouse game of anti-submarine warfare, there is no guarantee the cat will win.

“If it can get out of the harbor into the open Pacific, it would be a real pain in the ass to find,” Chun In-bum, a retired general who formerly commanded South Korea’s Special Warfare Command, told Asia Times.

What appears to be new North Korean intercontinental ballistic missiles during a military parade in Pyongyang on October 10, 2020. Photo: screen grab / AFP / KCNA

Pre-deployments vs pre-emptions

Paradoxically, the potential of their new weapon generates a huge risk for Pyongyang’s military brain trust to mull.

For most of the decades since the US and South Korea signed their mutual defense treaty at the conclusion of the Korean War in 1953, the defense of South Korea was paramount: It was within reach of North Korea, the US was not.

But with Kim now wielding both ICBMs and nuclear weapons, the strategic calculus has shifted. US defense planners must prioritize the national interest.  

Submarines are “second strike” deterrents – meaning that if a nation’s land-based systems are taken out by an enemy’s first strike, surviving submerged assets can retaliate. If North Korea follows this doctrine in times of tension, Pyongyang might pre-deploy boomers into open water.

And if actual hostilities appeared imminent – which, given the likelihood of troop movements and increased signal traffic, would become known – the US might be tempted to obviate Pyongyang’s “second strike” capability by preventing an SLBM-armed vessel from slipping its moorings.

“North Korea, in getting this capability, is inviting an attack,” said Chun. “There are US military and security professionals who would advocate to attack first.”

That pre-emption of a pre-deployment could be apocalyptic. However deeply dug in a submarine pen might be, the US B61 nuclear weapon “is capable of destroying a target that is up to 300 meters underground,” Chun said.

While that scenario is vexed – any White House decision to commence hostilities against North Korea, let alone with atomic weapons, would be politically agonizing – the ripples of Pyongyang’s missile programs are already causing waves around the region.

Since the cancelation of Japan’s Aegis Ashore missile defense program in 2020, hawks have been agitating for their nation to acquire a first-strike capability. Although newly minted Prime Minister Fumio Kishida is seen as dovish on defense, North Korean developments are offering those hawks an increasingly open door to push on.

“North Korea’s remarkable nuclear and missile technology development is something we cannot overlook, Kishida said following the North’s SLBM test.

“Amid this situation, I’ve already given instructions to revise our country’s national security strategy, including considering the option of acquiring the so-called capability to strike enemy bases.”