. That would be the ninth attempt. There have been eight test firings so far, all of them in a seven month period (April-October) in 2016. According to South Korea and the United States (which monitors such tests closely) all eight tests were failures although North Korea described one of the two June 22nd tests as a success and everyone agreed that the other June 22nd test was a partial success.
North Korea has apparently devoted considerable resources to perfecting its Hwasong 10 IRBM (Intermediate Range Ballistic Missile). This appears to be the most effective design the North Koreans have come up with, despite the fact that none of the test launches was a complete success. Another Hwasong 10 is being prepared for launch, apparently by November 7
Also known as the Musudan or BM-25 the Hwasong 10 was first seen in public during a 2010 parade and it was unclear if the Hwasong 10 really existed because there were no tests until 2016 although in 2013 two Hwasong 10s were spotted (by aerial photos) at a coastal missile launching base. But those two Hwasong 10s were removed from the base for unknown reasons and none were actually launched until 2016. The 18 ton Hwasong 10 can, depending on how heavy a warhead is carried and how the liquid fuel engines are tweaked and what combination of fuels are used, travel at least 3,000 kilometers and, best case, 4,000 kilometers. At that range the smaller warhead (less than half a ton) would have to be nuclear to justify the expense.
North Korea has been trying to develop a reliable IRBM since the 1990s. A lot of that works was based on Russian ISBM technology obtained in the 1990s. This was confirmed when it was discovered that North Korea obtained all or parts of a Russian R-27 SLBM (submarine launched ballistic missile) in the 1990s. This was 1960s vintage tech that was replaced in the 1970s by more modern designs. But many of the 492 R-27s produced were recycled for scientific research until 1990. After that it was believed that all or much of one missile was illegally sold as “scrap” to North Korea. This was deduced from the fact that after the Soviet Union collapsed in 1991 North Korea bought a lot of discarded Russian weapons for scrap (none of which was supposed to be operational stuff) and it was later discovered that some of the scrap was remilitarized by the North Koreans. An example of that was the Hwasong 10 , which looked a lot like the R-27. While the R-27 tech was probably also used for the North Korea KN-11 SLBM there earliest pictures of the Hwasong 10 showed the missile being carried and launched from a large truck, not a submarine.
Since Kim Jong Un came to power in 2011 he has launched more than twice as many ballistic missiles in five years than his father did during his 18 year reign. Kim Jong Un also built and launched more longer ranged missiles. Most (a little over half) of the Kim Jong Un launches were of short range (under 1,000 kilometers) SCUD types. Some 35 percent were multi stage missiles with ranges of 1,500 to 4,000 kilometers. The rest were the new SLBM (submarine launched ballistic missile).
Kim Jong Un is believed to have increased production of new ballistic missiles; to fifty or more a year. He needs this to maintain his current inventory of at least a thousand ballistic missiles. Over 80 percent of these are SCUD types and all the longer range North Korean ballistic missiles use liquid fuel. This means they have a limited shelf life and must either be rebuilt or replaced every ten of twenty years. Otherwise they become unreliable and often more dangerous to their users than to the enemy. But with IRBMs and some reliable nuclear warhead Kim Jong Un could make threats his father and grandfather could only dream about. And Kim Jong Un is doing it on a miniscule budget using ancient (by ballistic missile standards) tech and recycled component designs.
South Korean missile experts have concluded that physical evidence indicates North Korea has not developed any new ballistic missile technology or even manufactured many new missile parts since 2012. The South Koreans are pretty certain of this because since 2012 they have been able to recover (at sea) components of North Korea multi-stage ballistic missiles and examine them. Most North Korean ballistic missile tests are into the sea and the North Koreans have not tried to stop the South Korean recovery (of missile debris) efforts. This would trigger a fight the South Koreans are ready for and one the North Koreans could not win. Currently North Korea is concentrating on building components to keep older missiles operational and new ones based on older designs.
Replacing the missiles Kim Jong Un has used so far would cost North Korea nearly $40 million, which could be used to buy more grain from China and reduce the malnutrition that is increasingly evident. Hundreds of North Koreans still manage to escape from North Korea each year, despite increasing government efforts to block these “defectors.” Most remain in northeast China, where there is a large population of Chinese who are ethnic Koreans. Foreigners are able to see and even talk to some of these “defectors” and most report that the most compelling reason to risk their lives to get out is hunger. Few if the recent migrants appear well fed and many are visibly malnourished. Those with knowledge of the nuclear or missile programs report that people working on those projects are well fed and generally prosperous. This is not popular in North Korea, especially those who risk their lives to get out.