North Korea doesn't have a lot of experience dealing with the press (because it rarely does) so when it gave its most detailed defense of its rocket launch this morning, it didn't go over so well. The official line revealed by Ryu Kum Chol, a senior North Korean space official, is that there's nothing to worry about because a) the rocket uses liquid fuel not solid fuel and b) if this was actually a ballistic missile, it would require a much larger payload than is currently being used. Since the whole world is watching this launch, they probably should've done some homework on their talking points.
Liquid fuel The first point is the easiest to shoot down (ha). As the Associated Press reported this morning, Ryu dismissed worries as "nonsense" saying "solid fuel is used to launch ballistic missiles, while the Kwangmyongsong-3 satellite will be sent using liquid fuel." While it's true that most sophisticated ballistic missiles use solid fuel, as the Claremont Institute explains, it's not all true that delivering a bomb can't be done with liquid fuel. As the institute explains, a ballistic missile can contain "either liquid or solid fuel." As recently as last year, Global Security Newswire reported that Russia obtained a nuclear-capable ballistic missile reliant on liquid propellant. As the report explained, "The three-stage weapon can launch from 180 feet below the ocean's surface, transport a payload totaling 2.8 metric tons and achieve a range approaching 7,500 miles."
Payload This is where the North Korean's defense has a little more to stand on. This morning, Ryu said the current rocket simply didn't have a payload capable of carrying a weapon. "Our satellite weighs 100 kilograms," he said. "For a weapon, a 100-kilogram payload wouldn't be very effective." You'll notice that Ryu merely stated the weight of the satellite, not the payload capabilities of North Korea's technology. On this subject, experts disagree. According to physicists David Wright and Theodore Posto, in an analysis of North Korea's program in the Bulletin of the Atomic Scientists, the country has made advancements in the area of payload heft. Speaking of Pyongyang's Unha launcher, they wrote that "if North Korea modified it for use as a ballistic missile [it] would have the capability to reach the continental United States with a payload of 1 ton or more." (For sake of comparison 1 ton is 907 kilograms, or more than nine times what Ryu says the satellite weighs.) At the same time, other analysts speaking with CNN say "there has been no indication that North Korea has the ability to make a nuclear weapon small enough to be a payload on a Taepodong-2." Of course, we're talking about a moving target. Last Tuesday, reports out of South Korea stated that "the North may be building a bigger, more powerful missile that could carry a bigger payload even farther than the Taepodong-2." Regardless, the North Korean PR machine certainly didn't calm any nerves today.