North Korea Reveals a Multiple-warhead Payload in Probable Failed Test
On June 26, the Democratic People’s Republic of Korea (DPRK or North Korea) launched a test missile that probably used the first stage of a Hwasong-16 solid-propellant intermediate-range ballistic missile (IRBM) and a new payload section. Pyongyang’s claim that the launch was a “separation and guidance control test of individual mobile warheads” as part of “securing the MIRV capability” appears credible.[1] North Korean media reported the test successfully released three independently targeted warheads and a decoy. Initial photo and video evidence indicated the booster probably performed correctly and did not rule out—but could not confirm—warhead releases. Thermal video of the test released by the Republic of Korea’s (ROK or South Korea) military on June 28, however, indicates the booster most likely failed at about a 100-kilometer (km) altitude and probably did not deliberately release reentry vehicles or decoys. Therefore, the test probably failed, and if so, North Korea mischaracterized the results—as it has sometimes done in the past.
Given the apparent failure, the test’s main significance is in showing that North Korea remains committed to developing multiple-warhead missiles and seemingly believes its efforts are far enough along that a flight test was warranted. The mention of releasing a payload decoy, which is a sensible means of trying to divert missile defenses, is also significant. However, if the booster failed prior to releasing its payload, the test would not have provided any important data for improving MIRV technology.
North Korea will almost certainly continue multiple warhead testing, perhaps relatively soon. At least several successful flight tests of longer duration and higher altitude over a minimum of a few years are likely before North Korea operationally deploys multiple warheads—especially if it is seeking MIRVs rather than less complex multiple reentry vehicles (MRVs). Assistance from Russia or entities in China could accelerate the timeline somewhat.
Successful MIRV development would underscore North Korea’s technical prowess and would further complicate the task of allied missile defenses. If North Korea ends up fielding a true MIRV, not just an MRV, there is the added military benefit of one missile being able to attack several widely spaced targets, thus increasing the “productivity” of each missile—especially the number of targets that a surviving missile force can retaliate against after absorbing a first strike. MIRVs also have the potential to significantly boost the number of deployed North Korean warheads for a given number of missiles and launchers, especially for ICBMs. But this depends on how the North chooses to allocate its relatively limited nuclear warhead production among many different weapons systems.
What Did North Korea Launch?
On June 26, the North conducted a missile test launch. Pyongyang reported in a June 27 press statement that the launch used “the first-stage engine of an intermediate-range solid-fuel ballistic missile.” An accompanying photo showed what appeared to be the first stage of a Hwasong-16 (HS-16) solid-propellant IRBM just after ignition, topped with a payload section covered by a payload shroud. In its two previous launches, the two-stage HS-16 had instead carried a maneuvering reentry vehicle (MaRV) or a boost-glide vehicle (BGV), both termed “hypersonic missiles” by North Korea. This may explain why initial South Korean reporting of the launch characterized it as a suspected hypersonic missile. The use on June 26 of only the first stage of the HS-16—which probably is based on the first stage of the HS-18 three-stage solid-propellant intercontinental ballistic missile (ICBM)—and a payload section not previously flown on the HS-16 suggests the missile was a specially configured test vehicle.
The North Korean characterization of the test missile appears to be accurate. The US and former Soviet Union often used test boosters modified from operational missiles and space-launch vehicles to conduct developmental reentry vehicle (RV) testing. The vehicle depicted in the North Korean photo is consistent with the claimed purpose, and the initial South Korean reporting of a “hypersonic” test is consistent with an HS-16 first stage having been used.
What Was the Purpose of the Launch?
North Korea reported that the launch was a “separation and guidance control test of individual mobile warheads” as part of “securing the MIRV capability.” Pyongyang claimed that “separated mobile warheads” were sent to “three coordinate targets,” along with a “decoy.”
This is the first mention by North Korea of multiple warhead development since Kim Jong Un reported in January 2021 that “the sector of national defence scientific research was conducting research into perfecting the guidance technology for multi-warhead rocket at the final stage.” MIRVs make sense for North Korea, particularly as a means of complicating missile defenses, and movement toward MIRVs had long been expected by outside analysts, even before Kim’s report.
This history, in combination with the depiction in the North Korean photo of a test missile with a payload section capable of housing MRV or MIRV warheads (although it could also house a single warhead), lends credence to the North Korean assertion that the development of multiple warheads was the purpose of the test.
Was the Test Successful?
North Korea reported that the test was successful, with the three warheads “guided correctly” and the release and effectiveness of the decoy “verified by anti-air radar.” It published a photo labeled “individual mobile warhead separation,” appearing to demonstrate the faint contrail of a very small object out in front of the main rocket plume and the brighter contrail of a larger object parallelling the main plume. It also released a photo captioned “decoy separation,” which appeared to show an object at the head of the main rocket plume curling away from it.
South Korea reported early on that the launch had failed in flight, exploding and scattering fragments over a wide area. Such a failure is consistent with the very short flight duration reported by Japanese government sources (six to 11 minutes) and the short distance between launch and impact points reported by the ROK (250 km). Moreover, Pyongyang has yet to release any video of the flight, and the depicted plumes all appear to have been within the Earth’s atmosphere, consistent with reporting from Japan’s Ministry of Defense that the launch’s maximum altitude was about 100 km (the point at which the international definition of the atmosphere ends). The short flight time and low altitude would be very unusual for MIRV testing, which normally occurs in the vacuum of space and needs time for the post-boost vehicle (PBV, or MIRV “bus”) that usually targets and releases the individual warheads to separate from the booster and conduct the necessary maneuvers.
On the other hand, the contrail photos released by North Korea and distant video of the flight taken by South Korean civilians did not show a large explosion from a catastrophic in-flight failure. Moreover, the reported trajectory would be consistent with ensuring ground-based radars in North Korea could observe any release of warheads and decoys, and South Korea has had a long history of denigrating even well-documented North Korean missile and space achievements.
In light of the above information, most outside observers judged as of June 27 that the booster probably functioned normally but were unable to confirm if multiple warheads had been released, although that appeared possible.
This situation changed markedly on June 28, when the South Korean government released thermal video excerpts reportedly taken by front-line military units. The clips show the missile climbing abnormally, rolling along its horizontal axis, tumbling out of control and exploding into multiple pieces.[2]
Based on the updated information, and in the absence of any North Korean corroboration of success, it appears most likely that the booster failed at about a 100-km altitude after much of its propellant had been expended, producing a relatively small-scale explosion and probably did not deliberately release reentry vehicles or decoys. (Such objects could have been part of the debris from the explosion.) The test probably failed, and if so, North Korea mischaracterized the results—as it has sometimes done in the past.
What Is the Significance of the Test?
Given the apparent failure, the test’s main significance is in showing that North Korea remains committed to developing multiple-warhead missiles more than three years after Kim’s mention of that objective and seemingly believes its efforts are far enough along that a flight test was warranted. That said, because of the stage at which the probable booster failure occurred, we do not know whether the test would have released MRVs or the claimed MIRVs, or whether it would have involved a PBV—which, with its associated maneuvering, guidance, and control, is the most technically challenging aspect of MIRVing.
The dimensions and mass of any multiple reentry vehicles carried are also unknown. This information would shed light on whether they were only test articles intended to validate a PBV and successful warhead releases or if they were meant to represent operationally deployable RVs. In the latter case, size and weight data would have implications for the number of warheads a given missile type could carry, the associated nuclear yield, and the operational risk of deploying such RVs without full-scale flight testing on ICBM-range trajectories (because smaller nuclear RVs are likely to be less robust and thus riskier to rely on operationally without such testing).
Another significant item is the North’s mention of releasing a payload decoy, which is a sensible means of trying to divert missile defenses that all major missile powers have employed on their strategic missiles. This, too, has long been expected by outside analysts. But the type, size/weight, verisimilitude and sophistication of any decoy are all unknown. The North’s claim that the decoy was monitored by an “anti-air radar” underscores the challenge it faces in gauging whether its decoys would be effective in fooling purpose-built Western anti-missile radars. Indeed, it is quite likely that alliance missile defense and intelligence-gathering sensors would acquire much more and better data on decoy (and MIRV) flights than the North Koreans could.
Although it is often said that test failures nonetheless produce worthwhile data that help improve and advance a missile program, that may not be the case this time. If, in fact, the booster failed prior to releasing any PBV or dispensing any warheads or decoys, then the failed test would not have provided any significant data in improving MIRV or payload development. The North would certainly have gathered data on the booster, but it has already been flown successfully on two launches of the full-up HS-16 IRBM and three of the HS-18 ICBM.
What Is Likely to Happen Next?
If the June 26 test failed during booster operation prior to payload deployment, North Korea would probably try to replicate it relatively soon, either after a brief evaluation of any booster failure or simply relying on the overall good track record (by Pyongyang’s standards) of the HS-16/HS-18 first stage.
If there was a failure during payload operation—or if the most recent South Korean video evidence is wrong and the test functioned as intended—then the North is likely to take more time to evaluate and tweak the payload.
Even if it was not a failure, this first test was too short in duration and at too low an altitude to have provided much benefit to multiple warhead missile development. At least several successful flight tests of longer duration and higher altitude, over at least a few years, are likely before North Korea operationally deploys multiple warheads, especially if it is seeking MIRVs rather than less complex MRVs.
Assistance from Russia or from entities in China could somewhat accelerate the timeline but would not obviate the likely need for at least a few successful flight tests.
Why Are North Korean MIRVs Important?
Successful development of MIRVs would underscore the technical prowess of North Korea’s missile program and boost the regime’s domestic and international prestige. From a military standpoint, MIRVs and even MRVs would further complicate the task of allied missile defenses by forcing them to cope with more relatively small objects in the same timeframe—not to mention throwing decoys into the mix. If North Korea ends up fielding a true MIRV, not just an MRV, there is the added military benefit of one missile being able to attack several widely spaced targets, thus increasing the “productivity” of each missile—especially the number of targets that a surviving missile force can retaliate against after absorbing a first strike.
MIRVs also have the potential to significantly boost the number of deployed North Korean warheads for a given number of missiles and launchers, especially for ICBMs. But this depends on how the North chooses to allocate its relatively limited nuclear warhead production among many different, mostly single-warhead, weapons systems (ICBMs, IRBMs, medium- and short-range ballistic missiles, submarine-launched ballistic missiles, land-attack cruise missiles, unmanned underwater vehicles, etc.). It remains to be seen how many multiple-warhead nuclear missiles the North chooses to deploy.
- [1]
Multiple independently targetable reentry vehicles (MIRVs) allow one missile to directly strike several widely separated targets, unlike multiple reentry vehicles (MRVs) that are dispensed shotgun-style without individual targeting.
- [2]
Minji Lee, “S. Korean military unveils video of N.K. missile exploding in midair,” Yonhap News Agency, June 28, 2024, https://en.yna.co.kr/view/AEN20240628006100315; and John Feng, “North Korean Missile Spirals out of Control and Explodes: Video,” Newsweek, June 28, 2024, https://www.newsweek.com/south-korea-releases-video-north-korea-missile-explosion-1918594.