On September 29, North Korea announced the previous day’s launch of “a hypersonic missile Hwasong-8.” It also released a photograph showing a liquid-propellant rocket resembling a shortened version of the Hwasong-12 intermediate-range ballistic missile (IRBM) in the early stages of flight. Atop the rocket was an arrowhead-shaped vehicle with stubby wings resembling a hypersonic glide vehicle (HGV), the reentry portion of a ballistic missile-based “hypersonic missile.” On October 12, the North released photos from Kim Jong Un’s attendance the previous day at the opening of “The Defense Development Exhibition Self-Defense 2021,” showing the “Hwasong-8” on a road-mobile launcher with a booster smaller than the Hwasong-12 and an HGV payload strongly resembling that used on the Chinese DF-17 missile.
Many pertinent aspects of the launch currently are unknown, including the success of the test and the accuracy and intended payload of the HGV. An HGV would only make a niche contribution to the North’s existing large ballistic missile force, however, primarily in providing another option to evade missile defenses. If the North intends to deploy credible HGVs, at least a few successful and longer-range tests will be needed, probably taking at least a few years.
The “Hwasong-8” was reported to use a “missile fuel ampoule,” the meaning of which is unclear but probably refers to loading the missile with propellants at the factory. Many have pointed to this as a signal of improvement in the survivability and operational utility of North Korean liquid-propellant missiles. In fact, those benefits come instead from the use of storable liquid propellants (that can remain in missiles for long periods of time without damaging them, unlike previous propellants), although “ampoulization” could provide easier and safer missile handling. More significant, the North foreshadowed “turning all missile fuel systems into ampoules,” suggesting it intends to continue to retain and improve its liquid-propellant ballistic missile force for the long term rather than shift to an all-solid force.
The launch also makes good on Kim Jong Un’s inclusion of hypersonic missile development in his speech to the Eighth Party Congress in January 2021, making it likely that other technologies he mentioned (such as solid-propellant intercontinental ballistic missiles) will be rolled out in the future.
Finally, we should not ignore the substantial political objectives North Korea had in making this announcement, seeking to bolster deterrence, trumpet its technological prowess, generate prestige and legitimacy, and underscore the foresight and accomplishments of the regime.
Takeaway One: Much Remains Unknown or Unconfirmed
No information is publically available thus far to confirm North Korea’s claims that the September 28 launch successfully demonstrated an HGV. (That said, the US government should be able to obtain substantial insight into the launch from infrared satellites.) Information from South Korea, presumably based on radar data, confirms the fact, time and location of a launch, and that a rocket booster was used. That information also noted the missile flew “shorter than 200 kilometers” at an altitude of around 60 km, (another source reports around 30 km) and showed “different flight features from the missiles the North previously tested”—a performance consistent with either unsuccessful separation of an HGV from the booster or with the HGV having flown beneath South Korean radar coverage. Interestingly, and unlike most other recent missile launches, North Korea did not report the range of the September 28 launch.
We do not know if the “Hwasong-8” booster will only be used for HGV testing and/or deployment, or if it will also be used with a traditional reentry vehicle as a medium-range ballistic missile (MRBM). The October 12 photos provide further indication that a road-mobile launcher was used, consistent with the use of such a launcher in the 2017 launch from the same location of the Hwasong-14 intercontinental ballistic missile (ICBM) that has a similar-appearing propulsion system.
As is usual with North Korean missiles, there is no information on the guidance system or accuracy of the HGV to corroborate Pyongyang’s claim that the “the guiding maneuverability and the gliding flight characteristics” of the HGV were “confirmed.” There was also no mention in North Korean reports whether the missile system is intended to use a nuclear or conventional payload (or to be dual-capable), although many commentators inferred a nuclear mission from the North’s characterization of the missile as a “strategic weapon” whose development and deployment is of “strategic importance.”
Takeaway Two: An HGV Would Be a Niche Contributor, and Take Time to Develop
Pyongyang no doubt relished some Western commentary that the HGV “could change the military equation in East Asia” and that the North was “joining a race headed by major military powers to deploy the advanced weapons system.” In fact, most of North Korea’s existing large and diverse ballistic missile force reenters at hypersonic speeds, and is as capable as HGVs of performing most missions. The one area where an HGV could make a meaningful addition is by using its greater maneuverability to provide another option—in addition to saturation attacks, early-release submunitions, penetration aids, maneuvering reentry vehicles, and possible future multiple reentry vehicles—to avoid and attack missile defense systems. Given the relatively limited number of radars and other key nodes of adversary missile defense systems, the substantially higher production and deployment costs of HGVs compared to traditional reentry vehicles, and the availability of other means of avoiding missile defenses, North Korea is likely to devote only a small portion of its missile force to HGVs if it sees them through to deployment.
It is unclear how long it would take North Korea to develop a reliable system. HGVs are very technically demanding due to the heating they experience during flight, the consequent need for advanced materials to manage that heat and the challenges of maintaining accuracy (especially for conventionally armed systems). Russia, which apparently deployed HGVs on liquid-propellant ICBMs in December 2019, had been working on HGVs since the mid-1980s (with a hiatus in the first several years of the 1990s), and conducted some 14 flight tests. China deployed an HGV strongly resembling that of the “Hwasong-8” on the DF-17 solid-propellant MRBM around 2019-2020, conducting at least nine flight tests between 2014 and 2017.
We do not know how much technology relevant to HGVs the North may have acquired from entities in Russia and China, and it has a long history of deploying ballistic missiles with much less flight testing than China, Russia/the USSR, or the US. That said, the technical demands of HGVs, and the likely need for fuller-range tests rather than the shorter trajectories North Korea often employs to avoid overflying Japan, suggest at least a few successful and longer-range tests would need to occur if the North intends to deploy a military meaningful HGV.
Given the oversized role political rather than technical factors seem to play in the timing of North Korean missile tests, and the potential political blowback from long-range missile tests, it would be reasonable to assume that deployment of a capable HGV (assuming that is what the North intends) is at least a few years away.
Takeaway Three: “Missile Fuel Ampoules” Are Not Such a Big Deal
A number of commentators have pointed out the significance of the North Korean statement’s reference to the “missile fuel ampoule” used “for the first time” in the September 28 launch. As is often the case with such statements, it is unclear what the North means by a “missile fuel ampoule.” Most likely, it refers to the Soviet/Russian practice of preloading the SS-N-6 and later liquid-propellant submarine-launched ballistic missiles (SLBMs) with propellants at the factory, and maintaining the fueled missile as a sealed unit for loading into the submarine launch tube.
Many commentators have seen “ampoulization” as permitting liquid-propellant ballistic missiles to remain fueled on a day-to-day basis. This would avoid the need to fuel missiles just prior to launch, which would add to response time, be potentially detectable by adversaries, add to pre-launch vulnerability, and provide an opportunity for preemptive attacks against the missiles during fueling before they could be launched. It should be noted, though, that North Korea has not made such claims to date.
“Ampoulization,” however, is not required to keep the latest North Korean liquid-propellant ballistic missiles fueled on a day-to-day basis and obtain these operational benefits. Rather, these benefits come from fueling these missiles with storable liquid propellants, which can stay loaded and ready-to-go for extremely long periods of time without damaging their propulsion systems, unlike the Scud-type propellants that can only be tolerated for a relatively short time. The Musudan/BM-25 (based on the Soviet SS-N-6 SLBM) and Hwasong-12 intermediate-range ballistic missiles (IRBMs), the Hwasong-14 and -15 ICBMs, and the “Hwasong-8” launched on September 28 (the booster of which appears to be a shortened Hwasong-12) all use storable liquids.
For example, the Soviet SS-7, US Atlas F and Titan-II ICBMs, using storable liquid propellants, apparently remained fueled and on alert for long periods without any form of “ampoulization.” Moreover, the SS-11 and probably later Soviet liquid-propellant ICBMs using storable propellants were not “ampoulized” in the same way as SLBMs. They were not fueled in the factory, but were emplaced in their silos empty and then fueled, where they stood on alert for years at a time. Instead, they apparently were “ampoulized” by using membranes to separate the engines and fuel plumbing from the propellant tanks. (It is unclear what practices China has followed with its ballistic missiles using storable liquid propellants.)
Furthermore, North Korea may already have deployed one or more of the Musudan/BM-25, Hwasong-12, -14 and -15. If so, based on the precedents of the above Soviet and US systems the missiles may be deployed fueled on a day-to-day basis—predating the “ampoulization” that North Korea said was only first introduced with the September 28 Hwasong-8 launch. North Korean missiles using Scud-type propellants would likely also avoid most of the operational problems attributed to unfueled liquids if they were fueled during a crisis period and dispersed to the field in a fueled state prior to war.
“Ampoulization” still could provide worthwhile benefits, especially for land-mobile missiles. Transporting and handling “ampoulized” missiles would be easier and safer, especially in the field, and particularly within an enclosed launch railcar. (Rail mobility would be particularly suitable for liquid-propellant ICBMs.)
Takeaway Four: Liquid Missiles Are Here to Stay
The most significant part of the North Korean statement on “ampoulization” was its noting “the military significance of turning all missile fuel systems into ampoules.” Since “missile fuel ampoules” are probably not germane to solids, this statement suggests that North Korea intends to retain and improve its liquid-propellant ballistic missile force for the long term rather than shift to an all-solid force.
All other things being equal, solid-propellant missiles generally provide worthwhile operational advantages over liquids, including: faster reaction time, easier and safer handling in the field, a smaller logistics train (and thus less vulnerable field deployments for mobile missile systems), and no need to engage in possibly vulnerable pre-launch fueling operations. But all things are not necessarily equal with solids, especially for North Korea, which is likely to see a number of important reasons to continue developing liquid-propellant missiles while also continuing to pursue solids:
- Pound for pound, liquid propellants are more energetic than solids, allowing a given-size liquid missile to have more range/payload capability than a solid of the same size, or for a smaller liquid missile to be used for a given range/payload level. North Korea, therefore, could find liquids especially attractive for applications calling for larger payloads—such as an HGV, multiple reentry vehicles, the post-boost vehicle plus multiple warheads of a multiple independently-targeted reentry vehicle (MIRV) payload, or multi-megaton single warheads.
- As solid-propellant rocket motors get larger, production becomes more challenging. Although North Korea is almost certainly pursuing larger-diameter solid motors for future IRBMs and ICBMs (and may also pursue large solid SLBMs of equivalent range), for now, all of its known IRBMs and ICBMs are liquids. Even if it does develop solid missiles of these sizes, it is highly likely to continue to pursue liquids as well, just as China and Russia continue to do.
- North Korea has some 35 years of experience developing, producing, deploying and operating liquids, and has substantial supporting infrastructure in place. It almost certainly has developed a substantial level of comfort in coping with and mitigating the operational downsides of land-mobile liquid missiles.
Takeaway Five: More New Developments Are to Come
Commentators have rightfully pointed out that the September 28 test makes good on Kim Jong Un’s report to the Eighth Party Congress, which included a “task” to “develop and introduce hypersonic gliding flight warheads in a short period.” Likewise, the North’s September 2021 tests of a long-range cruise missile made good on another passage in that same report. We can clearly expect other as-yet-unveiled capabilities mentioned in that report to be rolled out at some point in the future, including solid-propellant ICBMs, long-range SLBMs, and “multi-warhead rockets.”
Takeaway Six: Much of What We Are Hearing and Seeing Is Politically Motivated
Finally, it is important not to lose sight of the fact that North Korea’s hypersonic missile announcement, like so many of its unveilings of new missile and nuclear technologies, includes a substantial political motivation. It remains to be seen whether the North wants to and is able to make capable and reliable deployed weapons systems out of the HGV and other new military technologies, or how long it will take. We do not yet know how many HGVs or other systems will actually be deployed, or how effective they will end up being. Until then, and certainly from now through at least the near term, Pyongyang is likely seeking domestic and international political benefits through these announcements: bolstering deterrence, trumpeting its technological prowess (including over South Korea), generating prestige and legitimacy, and underscoring the foresight and accomplishments of the regime.
Given the high level of “hype” surrounding hypersonic missiles totally unrelated to North Korea, it is not surprising that North Korea decided to use HGVs at least in part for such purposes. And Kim’s speech at “The Defense Development Exhibition Self-Defense 2021” and the exhibition itself—showing not just the Hwasong-8, but all of the missiles North Korea has unveiled over the past five years—underscore the degree and importance of the political motivations behind the “hypersonic missile.”
“Hypersonic Missile Newly Developed by Academy of Defense Science Test-fired,” Korean Central News Agency (KCNA), September 29, 2021.
“Kim Jong Un Makes Commemorative Speech at Defense Development Exhibition,” Rodong Sinmun, October 12, 2021.
These storable propellants are nitrogen tetroxide (N2O4) oxidizers and unsymmetrical dimethylhydrazine (UMDH) fuel. Analysts typically note that these propellants are more energetic than the kerosene and IRFNA (inhibited red fuming nitric acid) propellants used in Scud- and Nodong-class liquid-propellant missiles, giving N2O4/UDMH-based missiles greater range/payload capability. The operational value of storable liquids compared to Scud-type propellants is often overlooked.
See: Pavel Podvig, Twitter post, September 29, 2021, 5:08 a.m., https://twitter.com/russianforces/status/1443140596772839424. The SS-11 and later Soviet liquid ICBMs were packaged in a canister at the factory, with the entire canisterized missile being loaded into the launch silo prior to fueling. Canisterization also has been suggested as a meaning of the North Korean use of “ampoule” (see Dr. Jeffrey Lewis, Twitter post, September 28, 2021, 6L51 p.m., https://twitter.com/ArmsControlWonk/status/1442985298757963780?s=20). The North’s statement that the September 28 launch introduced “ampoules” for the first time would not seem to be consistent with “ampoules” being “canisters,” however, given the previous use of canisters with the KN-24 and KN-25 solid-propellant short-range ballistic missiles. (See Michael Elleman, “Preliminary Assessment of the KN-24 Missile Launches,” 38 North, March 25, 2020, https://www.38north.org/2020/03/melleman032520; and “KN-25,” Military Today, accessed on October 13, 2021, http://www.military-today.com/artillery/kn_25.htm.) In any case, canisterization would not be required to achieve the operational benefits commentators have identified for “ampoulization,” although it would ease missile environmental control (beneficial for N2O4/UDMH propellants), handling, and transport.
“On Report Made by Supreme Leader Kim Jong Un at Eighth Party Congress of WPK,” KCNA, January 9, 2021.
For example, see: Ankit Panda, Twitter post, September 29, 2021, 12:29 p.m., https://twitter.com/nktpnd/status/1443251527179771905.