By John Schilling
Less than a month after their first successful ICBM test, North Korea has done it again. The missile tested on July 28 appears to be identical to the liquid-fueled KN-20 (Hwasong-14) missile launched on July 4. This missile, however, demonstrated substantially greater range—possibly sufficient to reach the east coast of the United States—but only with a substantially reduced payload. Second, possibly because of the reduced reentry vehicle (RV) weight, the RV appears to have disintegrated before reaching the ground, and thus the test may not have been completely successful. Third, this was the first time the North Koreans have conducted at launch at night, suggesting an emphasis on demonstrating operational rather than experimental launch procedures.
While Pyongyang may have an ICBM, the threat is currently limited to unsophisticated warheads against targets on the US west coast. North Korea will likely have to turn to an upgraded design to achieve their goal of a robust capability to retaliate against targets on the east coast, including Washington, for any attack on North Korea. While the KN-20 may have some deterrent value even in its current, unreliable form, it will likely take another year or two of work to achieve full operational capability. If the North pursues the objective of fielding a new solid-propellant ICBM, that will likely only be another few years beyond that.
The combination of increased performance and a night launch, contrary to North Korea’s hopes, reveal the probable failure of this test. Rather than landing far out to sea, this missile entered the atmosphere within sight of Japan, and it did so in a clear night sky. Several cameras on the Japanese island of Hokkaido caught the incandescent trail of the reentry vehicle. As my colleague Michael Elleman notes, the trail flashes briefly and brightly as the missile descends for 6-8 km, and a second or so thereafter breaks up into at least two visible objects and a vapor trail. The initial flash could be due to the reentry vehicle passing close to a reflective cloud, or it could be a part of the heat shield breaking off and vaporizing. Whatever the cause of the flash, the subsequent breakup is telling. We cannot be certain, but it seems unlikely that a warhead would have survived that experience.
The missile was reported to have reached an altitude of over 3,700 km, remaining airborne for 47 minutes. That’s a substantially higher level of performance than what the missile displayed on its first launch. This means, if the missile had been launched on a maximum-range trajectory, it could have reached Chicago or possibly even New York City. North Korea has given us a clue as to how that happened, with a press release indicating that the number of engines has increased. The trajectory of the first KN-20 indicates that its upper stage was propelled by a set of two vernier engines from an old Soviet submarine-launched ballistic missile whose technology is known to have fallen into North Korean hands. This same propulsion system was used on North Korea’s successful Unha space launch vehicle, but doesn’t produce enough thrust for optimal performance with heavy nuclear warheads. There is room in the upper stage to add a second pair of vernier engines, and we suspect this was done.
http://www.38north.org/2017/08/jschilling080117/
