North Korea has just fired a ballistic missile from a Sinpo-class submarine off of the Sea of Japan. While North Korean media claimed the test was a success, the evidence is clear that the missile failed to achieve the desired range. U.S Strategic Command tracked the missile in flight and determined that it flew only 30 km before dropping off radar, far short of the 300 km that would be needed for a successful test.
Initially, the missile tested was suspected to be a KN-11, a variant of the Soviet R-27 SLBM. Recently the North Koreans have built and attempted to fire a number of missiles using the R-27’s engine as a base. Just last week a test launch of a Musudan IRBM using the same engine failed on the launch pad. Kim Jong Un’s newest ICBM, the KN-08 is thought to be powered by two of these engines in a side-by-side configuration.
However, experts like Jeffery Lewis have suggested that this missile might utilize a solid fuel engine. In which case, today’s missile may use the North’s recently tested solid fuel rocket engine or a KN-02 engine. The current theory in the arms control community is that the missile is utilizing the newer engine. while the KN-02 has undergone much more testing, it is fairly weak; only able to throw a 485 kg warhead 160 km.
With a nuclear warhead expected to weigh around 1000 kg, a North Korean SLBM would require much more thrust to achieve any reasonable range. The new engine is therefore much more likely.
A working solid fuel missile is cause for concern. Solid fuel missiles can be kept on alert much longer and launched much faster than their liquid fueled counterparts. This greatly compresses the necessary response time. The American minuteman III for example can literally be launched within a minute. Liquid fueled missiles on the other hand can take up to 15 minutes to launch.
Solid fuel missiles also use more energetic fuels, which generally give them more range and greater lifting capacity. Knowing North Korea, this technology will likely be transferred land-based missiles to create more effective ICBMs in the future .
Aside from the solid fuel missiles, the creation of a submarine based nuclear deterrent would also be a big step for North Korea. The DPRK’s Sinpo-class submarines are diesel powered, and likely based on older Golf II-class Soviet submarines. They lack the range to reach the mainland United States, but could still form the basis of a sea-based deterrent capable of striking South Korea or Japan.
Submarines are much harder to track and destroy than fixed sites like silos or airfields. Nuclear weapons states like the United States and Russia generally field them as a second strike option, so even if a preemptive nuclear strike destroys most of their land-based nuclear weapons, the submarines will still be able to retaliate.
Even if the Sinpo-class is based on older technology, the creation of such a deterrent would complicate a war with the North. They would require assets like submarines and destroyers to track them so they could be destroyed before they get into launch position.
While this test was a failure the DPRK did get farther than their last attempts. The last SLBM the DPRK tested only managed to eject out of the launcher before falling into the sea. This missile not only managed to achieve ejection, but first stage ignition and at least limited flight. The new missile clearly works, even if this particular test was unsuccessful. This is a worrying development as it paves the way for not only more advanced missiles, but a new submarine based launching platform as well.