Hwasong-15 changes show improvement of North Korean ICBMs

Posted on : 2017-12-01 21:35 KST Modified on : 2019-10-19 20:29 KST
The new missile has a longer fuselage, an extra engine, and equal stage boosters
Comparing the Hwasong-14 and Hwasong-15 missiles
Comparing the Hwasong-14 and Hwasong-15 missiles

The Hwasong-15 ballistic missile that North Korea launched on Nov. 29 had a longer fuselage than the Hwasong-14. Changes were also detected in the rocket engine and in the shape of the warhead. Overall, these changes appear to back up assessments that the ballistic missile’s performance has improved. On Nov. 30, the South Korean military released its initial assessment that the Hwasong-15 represents a “new type of missile.”

On Nov. 30, North Korea released video footage on Korean Central Television and 42 photos in the Rodong Sinmun depicting the flight of the Hwasong-15, which it launched the previous day. These photos and footage show the Hwasong-15 being loaded and transported by a 9-axle transporter-erector-launcher (TEL) and then fired from a separate launchpad. The Hwasong-14 was transported on an 8-axle TEL, indicating that the new missile has a longer fuselage. This is presumed to mean that the missile is bigger, and thus has more thrust. And indeed, the Hwasong-15 exhibited tremendous thrust in its launch on Nov. 29 by soaring to an altitude of 4,475km, much higher than the Hwasong-14 when it was launched in July.

Two engines are combined to make a one stage rocket in the Hwasong-15 ICBM
Two engines are combined to make a one stage rocket in the Hwasong-15 ICBM

Changes are also noticeable in the Hwasong-15’s first-stage rocket engine. The pictures released by North Korea show flames blasting from two clustered engines on the first-stage rocket. This contrasts with the Hwasong-14, which had one main engine. The Hwasong-15 appears to have added an extra engine to create more thrust.

The second-stage propulsion was different, too. The propulsion boosters for the first and second stages on the Hwasong-15 were nearly the same thickness, making them look like a single object. On the Hwasong-14, in contrast, the second-stage propulsion booster was thinner than the first-stage booster. This suggests how much bigger that Hwasong-15’s second stage has become.

These changes appear to have been what the North Korean media was referring to when they reported that “the accurate operation of a high-output engine that enables thrust vector control and an engine with high specific impulse were confirmed” during the text launch of the Hwasong-15. The “high-output engine” appears to be the first-stage propulsion booster and the other “engine” to be the second-stage booster.

Both the Rodong Shinmun and the North Korean Central News Agency published photos of the new Hwasong-15 ICBM that was launched on the morning of Nov. 29. About 40 photos of the missile were published in the Rodong Shinmun on Nov. 30
Both the Rodong Shinmun and the North Korean Central News Agency published photos of the new Hwasong-15 ICBM that was launched on the morning of Nov. 29. About 40 photos of the missile were published in the Rodong Shinmun on Nov. 30

In addition, the Hwasong-15’s warhead was blunt and rounded, which contrasts with the sharp, pointed warhead on the Hwasong-14. It has been suggested that this might be a MIRV, or multiple independently targetable reentry vehicle. A MIRV is a ballistic missile that is loaded with several warheads that can simultaneously strike multiple ground targets during flight.

“The shape of the protective shroud, which would contain the reentry vehicle, appears to have been designed with a MIRV in mind. That doesn’t mean that the Hwasong-15 was loaded with a MIRV,” said Jang Yeong-seok, a professor at the Korea Aerospace University.

But Kim Dong-yeop, a professor at the Kyungnam University Institute for Far Eastern Studies, thinks it is unlikely that the missile was carrying a MIRV. “The roundness of the warhead tip appears to be connected with reentry, but not with a MIRV,” he said.

“Based on the initial results of our analysis, I can say that we believe the Hwasong-15 to be a new type of missile,” said Roh Jae-cheon, spokesperson for the Joint Chiefs of Staff, during a press briefing on Nov. 30. “The Hwasong-15 exhibits clear differences with the previously unveiled Hwasong-14 in terms of the appearance of the warhead, the connection between the first and second stages, and the overall size.”

When asked whether the Hwasong-15 represented technological progress, Roh said, “Even the data released yesterday [Nov. 29] showed changes in the maximum altitude. There appears to be some progress, but a more accurate conclusion will require further analysis.”

But some are citing the results of a simulation to argue that the Hwasong-15 was carrying a light warhead at launch to lengthen its range. “The engineering model used for this analysis [of the Hwasong-15] indicates the missiles were tested with a 150 kg payload,” wrote Michael Elleman, a senior fellow with the International Institute for Strategic Studies (IISS), a British research institute, in an article carried by the North Korean affairs website 38 North on Nov. 29. That would mean that, even if North Korea could make a nuclear warhead weighing less than 100kg to load on the Hwasong-15 missile, the atmospheric reentry vehicle would have to weigh less than 50kg.

“It is also unlikely that North Korea has…the technologies needed to build a 50 kg re-entry vehicle capable of protecting the warhead during the high-temperature, high-stress environment experienced during descent through the atmosphere,” Elleman wrote, noting that carrying a payload weighing even 500kg would shorten the Hwasong-15’s range to 8,500km. According to this analyst, a Hwasong-15 carrying a functional warhead would only be able to reach the west coast of the US.

By Park Byong-su, senior staff writer

Please direct questions or comments to [english@hani.co.kr]

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