August 9, 2011:
Japanese intelligence believes that North Korea is close to putting into service their new RSM-25 (or Musudan) ballistic missile. It was only last year that a military parade in North Korea featured the first public appearance of the long rumored RSM-25 missile. This is a variant of the Russian SS-N-6 submarine launched missile. The North Korean version is believed to weigh 20 tons and have a range of over 3,000 kilometers. The Japanese believe the range of the North Korean missile may be as much as 4,000 kilometers. It is believed that the North Korean version, using solid fuel rockets, was tested successfully two years ago.
The SS-N-6 is a 1960s vintage ballistic missile, and is known in Russia as the R-27. SS-N-6 is a NATO code name for the R-27. This was Russia's first true submarine launched ballistic missile (SLBM), and sixteen of them were carried in Yankee class SSBNs (missile carrying nuclear submarines.) The 12 ton R-27 had a range of 2,800 kilometers and used storable liquid fuel. This means it can be ready for launch in less than half an hour.
After the R-27 was replaced by more modern missiles in the 1970s, the missile continued to be used for scientific research until 1990. By that time, 492 R-27s had been launched, 87 percent of them successfully.
It would be very embarrassing for the Russians if someone had illegally exported SS-N-6/R-27 missiles to North Korea. It is more likely, and was been reported a few years ago, that the Russian organization that designed the R-27 illegally sold the plans to North Korea. This was supposed to have happened sometime in the 1990s, and the main reason for the deal was so that North Korea could obtain the R-27 missile guidance technology. The Russians kept improving the guidance system of the R-27 through the 1980s, while the North Koreans were desperate for missile guidance technology. But it appears that the North Koreans built at least one R-27, and may have incorporated R-27 technology in some of their other long range ballistic missiles. The North Koreans were apparently pleased with the R-27 design, and spent the time and effort to change it so that Musudan used more reliable solid fuel rocket motors, than the original liquid fuel ones.