SEOUL • North Korea's latest test-firing of a submarine-launched ballistic missile (SLBM) showed that the regime has made rapid progress in SLBM technology, experts have said.
North Korean leader Kim Jong Un declared Wednesday's test-firing "the greatest success", which puts the country in the "front rank" of nuclear military powers, its official media reported on Thursday.
Experts say North Korea's SLBM launch, the third one this year, appears to have been Pyongyang's most successful to date. The missile flew about 500km and entered Japan's air identification zone before falling into the Sea of Japan.
The SLBMs that North Korea tested on April 23 and July 9 flew about 30km and 10km respectively.
Significantly, the latest missile reportedly managed to reach a height of 400km, reported The Hankyoreh in a news analysis piece.
If the launch tube had been lowered to the correct angle, the missile could presumably have flown more than 1,000km.
According to a report compiled by the US Korea Institute at the Paul H. Nitze School of Advanced International Studies at Johns Hopkins University, North Korea's SLBM could become a legitimate threat by 2020. "Assuming the current rate of development, while North Korea still faces significant technological challenges, including building of a new class of submarine to carry the missile, it is on track to develop the capability to strike targets in the region - including Japan - by 2020," said the report, which was posted on 38 North, a website that tracks North Korea's missile development.
To strategically deploy SLBMs as a deterrent, a submarine needs to be able to cruise below the surface undetected for a long period of time.
But Mr Masao Kobayashi, a former Maritime Self-Defence Force submarine commander, told Japan Times North Korean submarines have not yet reached that point, especially in terms of noise level.
Missile experts say the North needs submarines even bigger than the 2,000-tonne Sinpo class it uses for the launch of ballistic missiles, said Korea Times.
The Sinpo-class submarine, which the North built in the 1990s by modelling a Russian Golf-class submarine, has only one missile launch tube, so it must return to base after firing one missile.