By Jun Ji-hye



North Korea will seek to show the United States its capability of striking a designated target on the American mainland in its next test of a ballistic missile, military officials and experts here said Tuesday.



Pyongyang is apparently preparing to launch an intercontinental ballistic missile (ICBM), and at stake is whether it has secured the necessary re-entry technology.



Whether the North will prove this during the possible ICBM test will determine whether it poses a real threat to the United States.



Pyongyang will concentrate all its efforts to succeed with this launch to use as leverage in negotiations with Washington, the experts said.



"The North showed off improved engine efficiency in a test last Saturday, and it will now focus on perfecting a long-range re-entry vehicle to make an operational ICBM," said a military official, asking not to be named. "This is a step toward completing its ICBM technology."



The North has never flight-tested its road-mobile KN-08 or KN-14 ICBMs, but they are believed to be capable of flying more than 10,000 kilometers, a range sufficient to reach the U.S. mainland.



After the engine test, North Korea leader Kim Jong-un hinted at another missile launch soon, saying, "The whole world will soon witness what eventful significance the great victory won today carries," according to the state-run Korean Central News Agency (KCNA).



During his New Year address, he said preparations for launching an ICBM had reached their final stages.



Re-entry technology refers to the ability to construct a shroud that covers the missile's warhead strong enough to withstand the extreme heat and other challenges involved in re-entering Earth's atmosphere from space. As the covered warhead re-enters the Earth's atmosphere at Mach 24, it needs to be capable of withstanding temperatures of around 7,000 to 8,000 degrees Celsius.



In March last year, after a simulation test, the North said it had secured the heat-resistance capability for its ICBMs.



But military authorities here downplayed the comment, citing that the test environment was far different from that in a real ICBM test, given that the temperature was only about 1,500 degrees Celsius.



Terence Roehrig, a professor at the U.S. Naval War College, said the latest engine test may have more likely been one for a space-launch vehicle rather than an ICBM. But he added: "These systems are very close and North Korea's space program has long been viewed as a cover for its ballistic missile capability."



He said some challenges including the capability of its re-entry vehicle still remain for the North's ICBM program, but every time Pyongyang tests any part of a missile system, its scientists learn something and improve their capabilities.



"Though estimates vary on how far North Korea has come, there is little doubt it is striving to have a system that can threaten the United States," he said. "Pyongyang may not have that capability now, but it will keep trying. If deterrence is the primary goal of North Korea, and I believe it is, the ability to reach the continental U.S. will be an important milestone for them."



The Ministry of National Defense has so far assessed that the North has made progress in some technologies related to the ICBM, such as stage separation and guidance and control systems, but the re-entry vehicle capability and engine performance remain dubious.



Following the North's latest engine test, however, the ministry said Monday, "We assessed that there was meaningful progress in engine efficiency with the test."



The ministry did not provide any more details, but sources said the thrust checked in the latest test was believed to have improved compared to one carried out Sept. 20. At that time, Pyongyang tested an 80 ton force rocket that burned for 200 seconds. Authorities believed that the thrust this time probably increased to about a 100 ton force, according to sources.



The KCNA reported, "The ground jet test of the Korean-style high-thrust engine recently developed by the Academy of the National Defense Science" was held Saturday at the Sohae Satellite Launching Ground, or the Dongchang-ri site, designated for the launch of long-range missiles.



The engine test took place while U.S. Secretary of State Rex Tillerson was visiting Northeast Asia, which included stops in Japan, South Korea and China. During the tour, Washington's top diplomat called for a new approach in dealing with the North, saying all options even including military choices remained on the table. Tillerson also said there would be no talks with the isolated state unless it gives up its nuclear ambitions.



Yang Moo-jin, a professor at the University of North Korea Studies, said, authorities need to pay attention to the fact that the North conducted the engine test ahead of major events such as the 85th anniversary of the founding of the Korean People's Army, and Chinese President Xi Jinping's visit to the U.S. next month.



"There is the possibility that the North could fire off an ICBM or launch a satellite soon as a provocation," he said.



The test was conducted to "confirm the overall technical indices of the engine such as features of thrust power in the combustion chamber, accurate movement of its turbine pump, control systems and various valves and their structural safety and reliability," the KCNA said, adding that the engine met technical expectations.



Kim called the successful test "a great event of historic significance" and "a new birth of the Juche-based rocket industry," it added.



A ministry official noted, on condition of anonymity, that the North's newly unveiled equipment seems to have one main engine with four connected back-up engines, saying, "We will have to closely monitor how the rocket engine will be used in the near future."



On the possibility of the ICBM test, the ministry official took a cautious attitude, saying, "We are currently conducting an analysis. It would be premature to confirm any details at the moment."



