KN-23B - Boost-Glide Warhead

North Korea appears to have developed a rail-mobile medium range missile with a hypersonic glide vehicle warhead launched to a high altitude which then glides to their destinations at hypersonic speeds. North Korea fired two short-range ballistic missiles on 25 March 2021. The next day Pyongyang announced that it has successfully tested new tactical surface-to-surface missiles and even disclosed images of the test. North Korea published pictures of a new missile just hours after U.S. President Joe Biden addressed the country's recent launches at his first press conference. Official Korean Workers' Party newspaper Rodong Sinmun published the image 25 March 2021 alongside a description of what it called a "newly-developed new-type tactical guided projectile" tested a day earlier in a launch overseen by ruling Korean Workers' Party Central Committee Secretary Ri Pyong Chol and other officials.

The weapon's warhead was said to have been "improved to be 2.5 tons with the use of the core technology of tactical guided projectile that was already developed." The regime's state-run news agency reported that the North's Academy of Defense Science conducted the launch of two missiles that “accurately hit the target” set in the sea some six-hundred kilometers off the east coast. This is further than Seoul's joint chiefs of staff's analysis of four-hundred fifty kilometers.

The Rodong Sinmun said North Korea has tested its new tactical surface-to-surface missiles developed by the National Academy of Sciences. The test was attended by high-ranking officials from the Workers' Party's Machine-Building Industry Department. However Kim Jong-un was not present at the site. Kim Jong Un was looking at new development plans and inspecting new double-deckers rather than supervising the missile tests.

The newspaper reported that the test has proved the credibility of the upgraded solid fuel engines and that Ri Pyong-chol, Kim Jong-un's top adviser, had reported the outcome of the test to the North Korean leader. According to local media sources, instead of watching the test, Kim toured a residential complex that is soon to be built in downtown Pyongyang. The Korea Central New Agency says Kim unveiled his plan to build a residential complex of loft apartments in Kangan District and toured the site.

South Korea's Joint Chiefs of Staff announced that the North fired two short-range missiles into the East Sea on March 25, at 7:06 a.m. and 7:25 a.m., from Hamkyongnam-do Province. The projectiles reportedly flew about 450 km at the altitude of 60 km. Intelligence officials of South Korea and the U.S. are analyzing the details of the fired missiles.

Having seen actual photos of the weapons unveiled by the North's state media, observers concluded that the "new tactical guided missiles" fired by North Korea appear to be an upgraded version of its KN-23 Iskander-class ballistic missile first showcased in a military parade in January 2021. The missiles that North Korea test-fired towards the Sea of Japan / East Sea appeared to be upgraded, modified versions of its KN-23 Iskander-class ballistic missile. Such Iskander-class ballistic missiles are harder to intercept than other missiles due to their so-called pull-up maneuver - the ability to shoot upwards dramatically during the final stages of descent making it harder to predict their flight trajectory.

The new variant was first showcased during North Korea's military parade in January 2021 and had not been tested prior to this launch. Despite the North's state media claiming that the new missile was equipped with a 2.5 ton warhead. Some suspected the warhead was actually smaller as the exterior of the warhead showed few changes from the KN-23, but the semi-conical warhead on both configurations is quite generous inn size, and phyical volume is only loosely correlated with warhead mass [heavy things may come in small packages]. At the January 2021 parade, the warhead of the new Iskander showed a sharper tip than the pre-existing KN-23 Iskander-class ballistic missile and a more bullet-shaped ogive configuration of the first version, which featured a complex multi-conic shape. Pyeongyang may be making such claim as a missile is widely believed to be able to carry a payload of at least one ton to carry nuclear warheads.

The overall vehicle is visibly longer, and the cylindrical barrel of the rocket motor body is significantly longer. Another change in feature that's noteworthy: the transporter erector launcher carrying the new Iskander appears longer with five-axles and ten wheels while the previous version had four with eight wheels. It's also believed to operate on solid fuel just like the KN-23 model which means it can be fired in less than 15 minutes.

What some found odd was the flight range discrepancy estimated by South Korea's Joint Chiefs of Staff - at 450 km - and the North's announcement of 600km. The initial consensus is that the radar technology used by South Korea is more accurate and reliable than the North's. North Korea plants a measuring device in the missile and measures the electronic wavelength emitted from the device. There could have been ten or so kilometers of measurement error since the South Korean military's radar can't measure the initial stages of the launch it has to reach a certain altitude and it can't capture the final destination due to the Earth's curved surface. But a 150-kilometer difference is huge. If the new Iskander had, indeed, flown 600 kilometers, it should have been picked up by South Korea's or Japan's radar since the missile would have landed near Japan's Exclusive Economic Zone.

It was widely expected that Kim Jong-un would preside over the testing. Instead, he attended a ceremony to break ground for building homes for his people. It's a distribution of work, and he toned down the provocation by not overseeing the tests. With the Biden administration due to unveil its North Korea policy in the coming weeks, these latest launches also came just four days after the regime fired two cruise missiles into the West Sea. The tests marked the North's first launch of ballistic missiles since President Biden took office.

On 28 April 2021 the South Korean military revised its assessment on how far North Korea's missiles launched toward the East Sea on March 25th traveled from an initial 450 kilometers to 600 kilometers. The Joint Chiefs of Staff on Thursday said that a comprehensive analysis from South Korean and U.S. intel shows that the missiles traveled further while conducting a so-called "pull-up" maneuver. Defense Minister Suh Wook on said the revision was mainly due to a "blind spot" in South Korean radar caused by the curvature of the Earth. He added that there are limitations in detecting how far the missile flew after descending below the Earth's horizon.

South Korea's Joint Chiefs of Staff said two missiles were fired at 12:34 and 12:39 in the afternoon of 15 September 2021 from North Korea's Yangduk, Pyeongannam-do Province. They flew some 800 kilometers and reached an altitude of some 60 kilometers. Since they were launched from inland rather than in a coastal area it's highly likely the weapons have been test-fired before and this launch is aimed at showing off the North's confidence in its missile capabilities and to test an increase in flight distance of pre-existing weapons.

Just looking at the flight distance and maximum height an expert said there's the possibility that today's test-fire could be the modified version of the KN-23 missile that was fired on March 25th using transporter erected launchers.

Some observers said this was an escalation of tensions from North Korea. It held a scaled-down military parade last Thursday to mark the 73rd anniversary of its founding, and followed that with the North's report of cruise missile tests and now this, the firing of ballistic missiles in which unlike the cruise missiles are a violation of United Nations sanctions. The latest missile launch was the fifth provocation by North Korea in 2021.

After the military parade, North Korea may be trying to escalate tensions by showing its new weapons. Although the North has developed nuclear weapons, its delivery of nuclear warheads is still incomplete. So through such launches, it's trying to gain the upper hand in negotiations with other countries by improving its delivery systems.

Japanese Prime Minister Yoshihide Suga called the launch an outrage and stated the missiles are presumed to have landed outside Japan's Exclusive Economic Zone. Japanese defense ministry sources say they now believe the two ballistic missiles North Korea fired on 15 September 2021 likely fell inside Japan's exclusive economic zone. The Japanese government earlier announced the two projectiles appeared to have fallen outside the EEZ, based on information it obtained right after the launch. The follow-up analysis suggests that the missiles flew about 750 kilometers with irregular trajectories at an altitude of under 100 kilometers. The last time a North Korean ballistic missile fell inside Japan's EEZ was in October 2019.

An EEZ is a 200-nautical-mile zone extending from a country’s coastline, within which that country can exercise exclusive sovereign rights to explore for and exploit natural resources, including energy production from water and wind, but over which it does not have full sovereignty. [UN Convention on the Law of the Sea, “Part 5]. Apart from idiosyncratic Japanese public sensitivities, there is nothing magic or of legal or security significance as to whether the missiles landed in waters that are part of Japan's EEZ. North Korean missiles frequently land in Japan’s EEZ and in the past North Korean rockets flew over Japanese territory on a trajectory to enter outer space.

When launching ballistic missiles, Pyongyang tested a new missile system designed to counter any force that threatens the country, the state-run news agency KCNA has cited North Korean marshal Pak Jong-chon as saying. "The railway-borne missile system serves as an efficient counter-strike means capable of dealing a harsh multi-concurrent blow to threat-posing forces", Pak Jong-chon, who is also a member of the ruling Workers' Party of Korea, pointed out.

The marshal also referred to the North Korean military's plans to expand the railway-borne missile regiment to a brigade-size force in the immediate future, and to conduct drills to gain "operational experience for actual war". The remarks came after KCNA reported that the missiles flew 800 km (500 miles) before hitting a target in the sea off North Korea's east coast. South Korea and Japan, in turn, said that they had detected the launch of two ballistic missiles from North Korea, which Seoul argued were fired from the central inland area of Yangdok.

KCNA reported "The 8th Congress of the Party, as part of the establishment of a new national defence strategy, organized a railway-borne missile regiment to increase the capability of dealing an intensive multi-concurrent blow at the forces posing threats to us at a time of conducting necessary military operations and to markedly improve the capability for more positively coping with various sorts of threats.

"The test firing drill took place for the purpose of confirming the practicality of the railway-borne missile system deployed for action for the first time, of judging the combat readiness and capability of performing firepower duty of the newly-organized regiment all of a sudden and of attaining proficiency in the action procedures in case of fighting an actual war."

North Korea confirmed on 15 January 2022 it test-launched ballistic missiles from a train in what was seen as an apparent retaliation against new sanctions imposed by the United States. North Korea’s official Korean Central News Agency (KCNA) said the drill was aimed at “checking and judging the proficiency in the action procedures” of the missile, adding the two guided missiles hit a set target in the East Sea.

South Korea’s Yonhap news agency quoted its military as saying the latest projectiles flew around 430km (267 miles) at an altitude of 36km (22 miles) and a top speed of Mach 6 (7,350 kilometres per hour), six times the speed of sound. The report by the North Korean state media came a day after South Korea’s military said on Friday it detected the firing of two missiles into the sea by its neighbor country in what became the third weapons launch this month.

The troops swiftly moved to the launch site after receiving the missile-test order on short notice and fired two “tactical guided” missiles that accurately struck a sea target, the report said. North Korea’s Rodong Sinmun newspaper published photos of what appeared to be two different missiles soaring above from rail cars engulfed in smoke.

Kim Jong-un, the general secretary of the Workers' Party of Korea, did not visit, but was instructed by executives of the Korean People's Army and the Academy of National Defense Science. It was also reported that "we discussed the issues to complete the national railway mobile missile operation system." It seems that the aim is to have various launch methods that make it difficult to identify the launch location of ballistic missiles.

South Korean media suspect that North Korea's multiple launches on 25 May 2022 of different kinds of ballistic missiles may have been aimed at showcasing its ability to hit targets with different ranges. South Korea's Joint Chiefs of Staff said the North fired three ballistic missiles from near Pyongyang toward the Sea of Japan. All three missiles were fired from the Sunan area in the North's capital city of Pyeongyang. The JCS said the first one, launched at around 6 a.m., is believed to have been an intercontinental missile. North Korea then launched a short-range missile at 6:37 am. As for the second missile, it was launched, but was soon unable to be detected. South Korea's military said further research is needed to see whether it had failed. The third, also believed to have been a short-range one, was fired five minutes later. The JCS says it traveled 760 kilometers reaching an altitude of about 60 kilometers. There are views that the last two were an upgraded version of Russia's Iskander missile. South Korean media reported an analysis that North Korea wanted to show it has a range of missiles which can attack either the US, Japan and South Korea by breaking their missile-defense systems.

Boost Glide Vehicle (BGV)

Hypersonic missiles fly at different altitudes and trajectories than traditional long-range missiles, such as ballistic missiles. There are generally two variants of offensive hypersonic missiles in development. Hypersonic cruise missiles are powered by advanced engines that use oxygen in the atmosphere for propulsion during their flight after they are launched and accelerated by booster rockets.

Hypersonic Glide Vehicles (HGVs) are a type of reentry vehicle that couples the high speed of ballistic missiles with the maneuverability of aircraft. Hypersonic glide vehicles are launched from booster rockets before gliding to their targets from higher altitudes in the atmosphere. Hypersonic cruise missiles fly closer to the Earth than hypersonic glide vehicles. Hypersonic glide vehicles have been studied since the 1930s, and extensively studied beginning in the mid-1940s. By the 1950's, balancing range and speed, hypersonic glide vehicles had emerged as the best choice over competing skip, skip-glide and ballistic trajectories for unpowered flight from above or near above the atmosphere.

Hypersonic Glide Vehicles (HGVs), also known as Boost Glide Vehicles (BGVs), are the next generation of conventional, long-range weapons. As a reentry vehicle, an HGV is capable of aerodynamic lift and gliding to change the trajectory from ballistic to non-ballistic, increase its range on reentry into the atmosphere, and provide it with the ability to maneuver. These vehicles are referred to as hypersonic because they can travel in the regime of speeds labeled as hypersonic by the National Aeronautics and Space Administration (NASA), i.e., greater than Mach 5 but less than Mach 25. The HGV is considered a glide vehicle because after a rocket accelerates it to a desired speed, the rocket and HGV separate, and then the HGV travels unpowered (glides) to its final destination/target.

The trajectory of a ballistic weapon is fairly predictable after its powered phase, because its movement is controlled by the laws of classic physics. An HGV, in contrast, is aerodynamically guided and can maneuver almost continually during its gliding phase, though any maneuvering reduces its range. Thus, while a ballistic weapon’s point of impact can easily be calculated after its powered phase, an HGV’s impact can be anywhere within its range.

Studies suggest that an HGV’s unpredictable maneuvering, like its speed, would help it penetrate advanced air defenses. Even the U.S. antiballistic missile defense system, arguably the most advanced in the world given its overall success rate (80% as of October 201325), has never been shown to hit a maneuvering target.

Rail Mobile Missile

Firing a missile from a train could add mobility, but some experts say North Korea’s rail networks running through its relatively small territory would be quickly destroyed by enemies during a crisis.

Rail vehicles to carry large missiles can probably be built much more easily than large wheeled vehicles. North Korea has a robust rail infrastructure, in contrast to the rudimentary road network. During the Cold War the United States considered several plans to base U.S. ICBMs in railcars that would have roamed the nation's rail network. Operation Big Star was floated around 1959, but this plan for rail basing the earlly Minuteman ICBM was deemed impractical. In December 1986, the White House announced plan to develop a rail system for basing part of the Peacekeeper Intercontinental Ballistic Missile (ICBM) force. To increase survivability of this force, 50 Peacekeepers would be mounted on 25 USAF trains, two per train. Development of the rail garrison deployment system was terminated in 1991.

In the mid-1980s, the Soviet Union began to deploy a 10-warhead rail-mobile ICBM, the SS-24. START limited the Soviet Union to 250 missiles and 110 launchers for mobile ICBMs, with no more than 125 missiles and 18 launchers for rail mobile ICBMs. The New START Treaty does not contain a sublimit on mobile ICBMs.

Both countries planned that the trains will be parked inside train ale1t shelters in secure garrisons at bases throughout the continental United States. The missiles will be kept on the trains in continuous strategic alert. In a crisis the trains would be "flushed", dispersing onto the nationwide railroad network, thus making it difficult for an enemy to determine where the missiles were at any given time to target them.

Both countries faced the challenge of hiding big missiles inside railcars that resembled those of normal civilian rolling stock ["Preservation of Location Uncertainty"]. Neither country developed a satisfactory solution to this problem. Presumably, North Korea will be able to disguise the much smaller rail cars needed for the KN-25B. Certain unique operational effectiveness characteristics associated with mobility on the rail network, such as the capability to restore missile accuracy in a specified time frame and to launch from the missile launch car, must be fully evaluated and demonstrated for the effectiveness of the system can be confirmed.

Rail-mobile deployment may provide a hightly survivable basing mode for North Korean missiles. But North Korea is small, and presumably stand-off UAV surveillancce radars would be able to comprehensively monitor the DRPK rail network. Therefore, ensuring that the missile trains blended in with normal rail traffic would be at a premium. This imposes significant size, and therefore range, constraints on rail mobile missiles. Liquid propellant missiles of anything beyond tactical range would be too large. No ICBMs, either solid or liquid fuel, could fit within normal North Korean rolling stock. Long range solid propellant missiles, notably SLBMs, would be sufficiently compact to be hidden, and these could cover all potential targets, other than CONUS. It would be rather easier for the DPRK to deploy these missiles in a rail mobile mode, than to develop and operate a fleet of missile-carrying submarines, though this option cannot be excluded.