Don’t Judge a Book by Its Cover: North Korea’s HS-18 Is Not a Russian ICBM

(Source: Korean Central Television)

An August 17 article by a prominent academic technical expert claimed that North Korea’s new solid-propellant intercontinental ballistic missile (ICBM), the Hwasong-18 (HS-18), actually is a Russian-supplied missile. The article also makes a series of claims about the capabilities and implications of the HS-18. Contrary to all of these assertions, however:

  • The HS-18 is neither a Russian ICBM nor is it “nearly identical” to one. It also is highly unlikely that Russia deliberately provided substantial ICBM technology. Most probably, North Korea developed the HS-18 on its own, benefitting from steady illicit acquisitions since the breakup of the USSR of significant ballistic missile technology directly from Russian companies and individuals, as well as dual-use items from entities in China and Russia.
  • There is no open-source evidence that the HS-18 carries, or has been flight tested with, ballistic missile penetration aids (penaids) to confuse missile defenses, despite the article’s claim that it “was designed from the beginning to be able to deploy large numbers of decoys.” It would, however, be logical for North Korea to develop and deploy penaids.
  • There is no evidence that any North Korean ICBM has carried or been flight tested with multiple warheads, despite the article’s contention that the HS-18 is “equipped to … deliver multiple thermonuclear weapons.” Pyongyang does, however, apparently intend to develop multiple-warhead ICBMs at some point.
  • North Korea has probably operationally deployed ICBMs since 2017 without having flight tested them on an operational trajectory, despite the article’s claim that “North Korea would have to flight-test any long-range ICBM to its full range.” The North probably deploys old-style reentry vehicles, like the US and USSR used in the 1950s and 1960s, that are large and robust enough to be highly likely to survive reentry without full-range flight testing.

Therefore, the North Korean nuclear ICBM threat to the US is not “new,” as the article maintains. The HS-18 will add incrementally to the threat posed since 2017 by ongoing deployments of liquid-propellant ICBMs, and it remains to be seen how many HS-18s will be deployed and at what pace. The article’s contention that the HS-18 “significantly enhances the threat to the United States mainland” is overstated.

Did Russia Provide North Korea With a Solid-propellant ICBM?

The HS-18 is not a Russian SS-27 Mod 1 (Topol-M) or Mod 2 (Yars) ICBM. (The article claims the HS-18 is an SS-27 Mod 2, which it mistakenly calls the Topol-M.) The HS-18’s general configuration—second and third stages sharing the same diameter, but smaller in diameter than the first stage—resembles these Russian missiles but also resembles the US Minuteman-III.

More important, contrary to the article’s contention that the HS-18’s physical dimensions are “nearly identical” to the SS-27 Mod 2/Yars, the North Korean ICBM is longer than all three of the above foreign ICBMs.

  • Based on measurements taken from the HS-18 launch canister previously paraded by North Korea and from photos of the first launch on April 13, 2023, the missile is some 25-26.95 meters long—significantly longer than the 22.5-meter Yars, the 21.9-meter Topol-M, and the 18.2-meter MM-III. (The article puts the HS-18 at “slightly longer than 22 m.”)

A new analysis by researchers at the James Martin Center for Nonproliferation Studies (CNS) provides several other technical explanations for why the HS-18 is not “nearly identical” to the Yars.

If It Did Not Provide Full-up ICBMs, Did Russia Provide North Korea With Substantial SS-27 Technology?

Although the possibility cannot be ruled out that the Russian Government deliberately provided North Korea with substantial technology and technical assistance in producing the HS-18, this is highly unlikely to be the case. Russia probably regards Yars technology as a “crown jewel” that it would be highly reticent to part with. It probably would be highly concerned that such technology in North Korean hands would be more vulnerable to acquisition by the US, which would facilitate the latter’s development of countermeasures. The USSR and now Russia have had a pretty solid 60-plus-year track record of not deliberately providing countries other than China with nuclear weapons or strategic missile technology.

Moreover, any such provision of technology needed to have occurred some 7-10 years ago to catalyze the development program that resulted in the appearance in 2023 of the HS-18. Although the advent of the Ukraine war arguably might provide Russia with an impetus to change its previous behavior and aid North Korean strategic programs (and the article points to the recent warming of bilateral relations as a sign of a recent ICBM transfer), such a shift would be too recent to explain the HS-18.

Did North Korea Obtain Russian Missile Technology on Its Own?

North Korea most likely developed the HS-18 on its own, but the missile’s development probably benefitted from steady illicit acquisitions since the breakup of the USSR of significant ballistic missile technology and know-how directly from Russian and other former-Soviet companies, institutes, and individuals. For example, in the early 1990s, North Korea almost certainly illicitly acquired design documents and hired scientists from the Makeyev Rocket Design Bureau responsible for Soviet/Russian submarine-launched ballistic missiles. The HS-18 likewise almost certainly benefitted from steady North Korean acquisitions over the past 25-30 years of dual-use equipment, components and materials from companies and individuals in China (especially) and Russia—both directly and by entities in both countries as fronts to obtain items from third countries.

As noted previously, both types of acquisitions are unlikely to have been directly conducted or authorized by the Russian or Chinese governments. Thus, the article’s contention that “this particular ICBM could not possibly have come into the hands of the North Koreans without the full support and cooperation of the Russian government” is probably incorrect. That said, both countries have under-prioritized export control enforcement for years, so it would not be unreasonable to be concerned about them turning a blind eye to illicit North Korean missile proliferation activity, particularly in the past few years of “great power competition” with the US. Moreover, North Korea’s cyber intelligence operations have been enormously successful over the past decade, which also could have provided the country with relevant technological insights from Russia, China and other countries, even the US. But again, because of the development cycle of ICBM technology, any information gathered would likely have to have been obtained by North Korea 7-10 years ago.

Does the HS-18 Carry Ballistic Missile Penetration Aids?

The article’s claim that the HS-18 “was designed from the beginning to be able to deploy large numbers of decoys” to confuse missile defenses (i.e., penetration aids or penaids) appears to be based on (1) the incorrect assumption that the missile is an SS-27, a system that is equipped with penaids, and (2) the contention that a “decoy canister” containing penaids was detached from the third stage during the HS-18’s July 12, 2023 second flight test.

Although it would be logical for North Korea to deploy penaids on its ICBMs given US homeland missile defenses, and it is almost certainly technically capable of doing so, there is no open-source evidence that penaids have been flight tested or deployed on Pyongyang’s ICBMs or its medium- or intermediate-range ballistic missiles. The “decoy canister” the article contends was seen in North Korean media coverage actually appears to have been the HS-18’s spent second stage, given its size, configuration, and color scheme—an assessment shared (and augmented with much technical detail) by the CNS researchers.[1]

The article’s claim that HS-18 penaids “will defeat any missile defenses currently being operated and modernized by the United States” depends heavily on the type, number, and quality of whatever penaids North Korea might ultimately deploy—all of which are unknown from open sources. Moreover, unless North Korea flight tests penaids while using its own sensors of types similar to US missile defense sensors, Pyongyang itself will have a difficult time being assured that its penaids “will defeat” US defenses. No such testing has been detected in open-source reporting, and it is unclear if the North has deployed sensors suitable for such testing. Indeed, the US is highly likely to be able to collect better information on the performance of any flight tested North Korean penaids than Pyongyang can, which would assist Washington in countering them. This, in turn, might be a reason why North Korea would deploy penaids without flight testing, relying instead on ground testing, simulation, and the element of wartime surprise.

Does the HS-18 Carry MIRVs?

The article’s contention that the HS-18 is “equipped to…deliver multiple thermonuclear weapons” also appears to be based on the incorrect assumption that the missile is an SS-27 Mod 2/Yars. (The Mod 1/Topol-M carries a single warhead.) It would be logical for North Korea to deploy multiple warheads on its ICBMs to increase target coverage and complicate US homeland missile defenses. Given sufficient flight testing, it is probably technically capable of doing so. However, there remains no open-source reporting of any North Korean flight testing of multiple warheads.

Kim Jong Un reported in January 2021 that the North was in the final stage of “conducting research into perfecting the guidance technology for multi-warhead rocket.” This is generally interpreted by outside analysts as Kim making the development of multiple-warhead strategic missiles an objective. But it remains unclear whether the “multiple warheads” Kim referred to are shotgun-style multiple reentry vehicles (MRVs) or the more sophisticated multiple independently targetable reentry vehicles (MIRVs) that are maneuvered to be released at widely dispersed targets by a separating post-boost vehicle (PBV, or MIRV “bus”) carrying the warheads as part of the missile’s payload. Although the article included a graphic suggesting that the HS-18 carries a PBV, there is no open-source evidence that the HS-18 released a PBV or multiple warheads in its two flight tests to date.

Does North Korea Have to Flight Test the HS-18 to Full ICBM Range?

The article contends that “North Korea would have to flight-test any long-range ICBM to its full range,” that testing on an ICBM trajectory is “essential,” and that “a nation could not have confidence that their missile could be used reliably unless they tested it on such a full trajectory.” Although this case is often made by outside analysts, North Korea’s historic track record of missile testing and operation strongly indicates it believes otherwise.

North Korean ICBMs have probably been operationally deployed since 2017, despite the lack of any testing on a full-range ICBM trajectory. In order to have adequate confidence that its ICBM reentry vehicles would successfully reach their targets on an operational trajectory even without such flight testing, the North probably deploys old-style reentry vehicles like the US and USSR used in the 1950s and 1960s that are large and robust enough to be highly likely to survive reentry. It has accumulated enough expertise and experience over the 40+ years of its missile program to field such reentry vehicles and have substantial confidence in their performance without full-range flight testing.

The use of such blunt-shaped and heavy RVs may also make it more difficult to deploy multiple warheads on the HS-18, especially MIRVs also requiring the weight of a PBV, given the missile’s diameter and apparent payload capacity. The much-larger-diameter, higher-capacity HS-17 liquid-propellant ICBM would be much easier to deploy with multiple old-style reentry vehicles.

Does the HS-18 Pose a Significant Threat to the US Homeland?

Finally, based on its contentions that the HS-18 is a Yars ICBM with multiple warheads and highly capable penaids, the article contends that North Korea “now has the ability to deliver these thermonuclear bombs to the continental United States” (emphasis added), and that “The new North Korean ICBM capability significantly enhances the threat to the United States mainland with a nuclear attack if the United States were to intervene in a crisis.” In fact, however, the North Korean nuclear ICBM threat to the US is not new; as noted above, it probably has been in place since 2017. The HS-18 will add incrementally to the threat posed since then by North Korea’s HS-15 and -17 liquid-propellant ICBMs, deployments of which are still being augmented. It remains to be seen how many HS-18s will be deployed and at what pace, which will be driven by North Korea’s nuclear weapons and solid-propellant production capacities and resource allocation decisions.

  1. [1]

    See Josh Smith, Trevor Hunnicutt and David Brunnstrom, “Latest North Korean missile sparks debate over possible Russian links,” Reuters, August 18, 2023,; Decker Eveleth. Twitter Post, August 17, 2023, 5:00 p.m.,; and Daniel Allen, Madeline Berzak, Michael Duitsman, Decker Eveleth, John Ford, Sam Lair, Jeffrey Lewis, and Tricia White, Arms Control Wonk, “Errors In Analysis of the Hwasong-18,” August 20, 2023,

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