Details are still scarce on last Friday’s missile test, but it appears to have been the missile provisionally named “KN-17” and described in sensational press reports as a “Carrier-Killer.” We have seen this missile before, certainly in the April 15 parade celebrating Kim Il Sung’s birthday, and possibly in two previous tests. All of these tests were reported by allied intelligence agencies as failures, and none were accompanied by the propaganda footage with which North Korea reports successful missile tests and demonstrations. Still, the North usually does manage to recover from test failures, and the consequences of an anti-ship ballistic missile in North Korean hands are worth considering. But we should also consider the possibility that the missile is intended for use against targets on land, which is a more plausible near-term threat.
The KN-17 appears to be a Scud derivative with small fins on the reentry vehicle, presumably for steering during the last seconds of flight. Such Maneuvering Reentry Vehicles (MaRV) are not new; the American Pershing II missile deployed in from 1983 to 1991 used such a warhead. So does the Chinese DF-21D, an anti-ship ballistic missile that clearly is intended to threaten US aircraft carriers. But there are other reasons to deploy such a system. The Pershing II was never intended for use against naval targets, and used its MaRV for precision attacks on land targets such as airbases and command and logistics centers. MaRVs have also been proposed, and possibly deployed, as a means of evading enemy missile defenses. All three of these prospects would be of clear interest to North Korea.
If Pyongyang does intend to use the KN-17 against naval targets, it would face a particularly difficult targeting problem. Allied military bases in South Korea and Japan can be reliably mapped in peacetime, and aren’t going to move. Aircraft carriers at sea are much more difficult to find. North Korean surveillance radar and coastal naval forces can probably track enemy warships within a few dozen miles of the North Korean coast, but while smaller allied warships may sometimes approach to such a distance, aircraft carriers will have little reason to do so. Long-range reconnaissance platforms like aircraft or submarines would need a great deal of luck to find a specific warship with the entire East Sea to hide in, particularly in wartime where the North’s planes and submarines would likely be destroyed long before they came close enough to spot an aircraft carrier. The ideal solution would be a constellation of satellites designed for maritime surveillance, but North Korean satellite technology isn’t up to that task yet. Pyongyang would also need an active radar guidance system capable of surviving a ballistic missile’s flight environment and providing precise guidance data during a steep, hypersonic terminal descent, which is also beyond their demonstrated capabilities.
Another problem with attacking aircraft carriers with the KN-17 is that the missile doesn’t work, at least not yet. But if the recent tests were failures, they were curious failures. The April 5 test reached a height of 169 kilometers, while travelling only 60 kilometers downrange. The US Pacific Command (PACOM) claims that the missile “pinwheeled” during flight. The performance, however, is about what we would expect from a successful Scud launch on a lofted trajectory, and beyond what would be possible from any missile that tumbled during powered flight. One possibility is that PACOM, not yet being aware of the KN-17’s experimental MaRV, instead tracked the missile’s larger booster. Once the MaRV separated, the expended booster would likely tumble randomly through the sky. But if we credit PACOM with tracking the right target, they may have been able to track the MaRV itself tumbling out of control during the terminal guidance phase. In either case, a MaRV test would explain the unusual trajectory – North Korea doesn’t need to use a high-angle trajectory to keep a mere Scud from e.g. overflying Japan, but they would want the impact region for a MaRV test to be someplace they could observe very closely.
The test on April 16 apparently exploded shortly after launch, and may not have been a KN-17 at all. We don’t yet have all the details on the April 28 test, but it may have been a repeat of the April 5 test. The maximum altitude of 71 kilometers was a bit lower than that of the earlier test, but still beyond anything a missile that failed during powered flight would be likely to reach. And the launch, from a west coast launch site, may have been an attempt to use a more traditional shallow-angle Scud trajectory by overflying the country with the warhead impacting just off the east coast. It isn’t surprising that a MaRV would experience failures in early testing. North Korea’s missiles usually fail in their first tests, and a MaRV is a trickier sort of rocketry than most. But North Korea usually does get their missiles working in the long run, and they appear to be taking the conservative approach of using a proven Scud missile as the basis for their first MaRV system.
North Korea probably won’t be able to sink any American aircraft carriers with the KN-17, not because the missile will never work, but because they won’t be able to find the carriers in the first place. There’s also the small matter that American aircraft carriers are closely accompanied by a pair of Aegis cruisers or destroyers, possibly the most capable missile defense platforms in existence. But we shouldn’t overlook the threat an operational KN-17 would pose to targets on land in South Korea. A missile capable of hitting a maneuvering warship at sea would be even more accurate against fixed targets on land, and could possibly evade defending Patriot missiles during its terminal attack. We’ve long considered North Korea’s hundreds of conventional Scud missiles to be mostly a harassment weapon due to their inaccuracy, but if they can reliably deliver half a ton of high explosives directly onto a crowded barracks, an ammunition dump or USFK headquarters, we might have a real problem. It might be time to start testing the Patriot system against maneuvering reentry vehicles.