Silo-Launched Ballistic Missile Capability Likely Tested By North Korea

North Korea now appears to be looking toward fast-responding silo-based missiles to further bolster its expanding nuclear forces.

byThomas Newdick|


North Korea has once again ramped up its missile launches against the backdrop of a new round of U.S.-South Korean military maneuvers. Significantly, the latest North Korean missile to have been fired was a short-range ballistic missile, or SRBM, which appears to have been launched from a ground-based silo, an important development that would increase the country’s ability to rapidly launch a nuclear strike against the South — or elsewhere, for that matter — with very little warning.

The KN-23 SRBM was launched Sunday, apparently from a silo that had been recently constructed at the Sohae Space Launch Center, in Tongchang-ri, in the western province of North Pyongan. Photos released by Pyongyang’s state media show a missile rising from what looks like a buried silo, although that cannot be stated for sure, and it remains possible that the imagery released is only intended to present this as fact. On the other hand, we do know that North Korea has been building a missile silo at Sohae, so it would seem at least highly likely.

Furthermore, the engine exhaust from the missile also appears to be vented out and upward on either side of the weapon at the point of lift-off, further pointing to a silo launch.

Exhaust plumes at the moment of launch are strongly suggestive of a silo launch. KCNA

“Our military detected one short-range ballistic missile fired from around the Tongchang-ri area in North Pyongan province at 11.05 am towards the East Sea,” South Korea’s joint chiefs of staff said in a statement yesterday. The East Sea is the Korean term for the Sea of Japan.

The missile reportedly flew almost 500 miles, while carrying what was described as a mock nuclear warhead. Once again, the missile test was attended both by North Korean leader Kim Jong Un, accompanied by his young daughter, Kim Ju Ae, who has become a more familiar presence at launches as of late.

The KN-23, with its solid-fuel motor, is already able to be brought into action much quicker than comparable liquid-fueled missiles, like the Nodong-1, an earlier medium-range ballistic missile developed by North Korea in the mid-1980s on the basis of the Soviet-designed SS-1 Scud. More modern but also using liquid propellant is the enormous Hwasong-17 intercontinental ballistic missile ICBM that we have examined in depth in the past. While liquid-fueled missiles need to be fueled before launch, the KN-23 can be fired more or less on demand.

With all signs pointing to yesterday’s launch being made from an underground silo, this suggests a potential new type of missile deployment, in addition to the mobile launchers of different kinds that North Korea already fields.

A TV screen at the Yongsan Railway Station in Seoul, shows file footage of a North Korean missile launch during a news program on March 19, 2023. Photo by Kim Jae-Hwan/SOPA Images/LightRocket via Getty Images

Having solid-fuel KN-23s deployed in silos would make it much simpler to bring these missiles into action and, at the same time, reduce the warning time should they actually be launched for real. The first indication of an incoming attack — with the exception of possible other forms of intelligence, like communications intercepts and network activity — would likely be the missile emerging from its silo. In contrast, a mobile ballistic missile launcher can be tracked by satellites or by other surveillance means in the lead-up to launch, showing foreign intelligence when it’s on the move and also revealing launch preparations and related activities that might point to imminent combat use. Once positioned for launch, a liquid-fueled mobile missile will need to be raised to have its propellant loaded, leaving it even more vulnerable to detection and attack.

Furthermore, there are questions about the practicality of North Korea’s mobile missile launchers, especially the larger ones, since local infrastructure doesn’t necessarily allow them to roam freely around the country.

With this in mind, it now seems to be the case that North Korea is at least trialing alternative methods of strategic missile deployment, with the latest being silos. Also in their favor, once the design is perfected, silos could be easier and cheaper to construct than relatively complex mobile launch vehicles, while not requiring the same level of supporting equipment.

There are, however, certain drawbacks to silo-based systems. While it may not be possible for an adversary to know the status of the missile in its below-ground silo, the static location means that it can be kept under permanent observation and a launch will be detected by a satellite as soon as it occurs. The question then is whether there is enough time to actually respond to the missile once launched. While South Korea is actively working on ballistic missile defense, as we have explored in the past, even an effective anti-ballistic missile system can simply be overwhelmed by the sheer weight of numbers presented by incoming weapons.

The fixed location of missile silos obviously leaves them vulnerable to a preemptive strike, as well, supposing the South wanted to pursue a ‘decapitating’ attack plan of this type. Here is another fundamental issue with silo deployment, in that it can dramatically raise the likelihood of the South (and/or the United States) finding itself forced to launch a preemptive strike, were it to fear that an attack from the North was imminent. Such a strike against the North would obviously have to account for every potential missile silo, while mobile missiles would also need to be addressed to remove the second-strike capability. At the same time, the stakes are raised for the North, which would be more inclined to launch a devastating surprise attack on the South before the adversary could render its silos inoperable through an attack of its own. Bearing in mind the relatively archaic sensor capabilities available to the North, the chances for a miscalculation in this kind of scenario are also raised accordingly.

However, at this stage it’s unclear if the apparent silo-launched KN-23 is intended to be fielded operationally or if it’s a case of the North using proven missile technology to investigate the practicality of silo launch of other missiles, perhaps including much longer-ranges ones, like the Hwasong-17. While the Hwasong-17 is liquid-fueled, with the disadvantages that it brings, it is considered capable of reaching targets across the United States.

Multiple examples of the Hwasong-17 ICBM roll through Pyongyang during a parade last month. At least 10 are visible here. KCNA

It has even been postulated that the silo-based KN-23 test could suggest that North Korea is not necessarily entirely happy with its other methods of deployment for the same missile — which by now include wheeled and tracked transport-erector-launchers (TELs), a rail-based version, as well as submerged variants intended to be launched from submarines or from barges in inland reservoirs.

On the other hand, it may simply be the case that the proven KN-23 is now being produced in relatively large numbers, such that new deployment options are being presented.

Whatever the long-term plan, it also seems evident that North Korea is able to construct missile silos rapidly, which further complicates matters for the South and its allies. According to Decker Eveleth at the James Martin Center for Nonproliferation Studies in California, North Korea began work on this particular silo in late January, meaning that it was able to deploy and then launch a missile from one of these structures in less than 60 days. This raises the possibility of the North embarking on a silo-construction program that could not only put shorter-range missiles like the KN-23 closer to the South but potentially also build dummy silos or real silos without missiles, to make it harder for any adversary to counter them.

As far as the North Korean regime is concerned, the latest missile launch was part of a series that was squarely intended as a response to recent military exercises involving the South and its U.S. ally. For Pyongyang, military drills of this kind are seen as rehearsals for an invasion and are met not only with missile launches but also threats of potential “immediate and overwhelming nuclear counterattack anytime” action in response.

The latest round of South Korean–U.S. maneuvers was described by North Korea’s state-run Korean Central News Agency (KCNA) as “frantic” and an “explicit attempt to unleash a war.” The Freedom Shield exercise, running for 11 days, is the largest of its kind in five years and on Sunday included participation by U.S. Air Force B-1B strategic bombers.

Two U.S. Air Force B-1B bombers flying over South Korea with Republic of Korea Air Force F-35A and U.S. Air Force F-16 fighter jets during a combined air drill on March 19, 2023. Photo by South Korean Defense Ministry via Getty Images

Meanwhile, KCNA said that North Korea’s exercises over the weekend were designed to enhance its “war deterrence and nuclear counterattack capability.”

“The drill also aimed to demonstrate our tougher will to make an actual war response and send a stronger warning to the enemy who expand their war drills for aggression,” KCNA added.

The agency also quoted Kim Jong Un, who said: “The present situation, in which the enemies are getting ever more pronounced in their moves for aggression against the DPRK, urgently requires the DPRK to bolster up its nuclear war deterrence exponentially.”

“The nuclear force of the DPRK will strongly deter, control, and manage the enemy’s reckless moves and provocations with its high war readiness, and carry out its important mission without hesitation in case of any unwanted situation,” Kim reportedly added.

With that in mind, the launch of four missiles this week is intended to signal Pyongyang’s readiness to stage a nuclear counterattack, although the actually operational viability of a silo-launched KN-23 remains questionable at this early stage. As well as this test, North Korea on Thursday conducted another launch of its Hwasong-17, the second so far this year.

Previous missiles launches in this latest round of tests included two other SRBMs fired on Tuesday last week, and two strategic cruise missiles launched from a submarine the previous Sunday.

This all fits in with Kim’s declared policy of an “exponential” increase in weapons production as part of North Korea becoming what he has described as an “irreversible” nuclear power.

As the North increases its nuclear rhetoric, it’s notable, too, that nuclear weapons are increasingly being openly discussed by officials in Seoul. Last month saw a significant development when South Korea and the United States staged tabletop exercises simulating a North Korean nuclear attack. At the same time, South Korean President Yoon Suk Yeol has called for an expanded role in the U.S. extended deterrence strategy, which includes plans for using nuclear weapons. In another new development, South Korea is also considering whether it might develop nuclear weapons of its own, in the future, to provide an independent deterrent against the North. Meanwhile, the mayor of Seoul also recently called for the building of nuclear weapons to provide beefed-up defenses against the North, even at the risk of international repercussions.

U.S. and South Korean exercises continued today, with the first large-scale Ssangyong amphibious landing exercises in five years. These will run for two weeks, until April 3, and there is every likelihood we will see more of North Korea’s missile arsenal put through its paces before the maneuvers come to an end.

Contact the author: