... North Korea's missile and nuclear capabilities do not add up to a nuclear Intercontinental Ballistic Missile, or ICBM. This third failure to create such a missile in as many attempts since 1998 likely represents the upper limits of what the country can do by stretching and adapting the Scud technology it acquired from the former Soviet Union.
This small, impoverished nation would need to make three key additional breakthroughs to turn this launch vehicle into a real nuclear-armed missile capable of reaching the continental United States.
First, North Korea has to develop a bigger, longer-range missile. MIT scientist Ted Postol calculates that the failed satellite appeared to weigh 150 to 200 kilograms (330 to 440 pounds) and was intended for a low-Earth orbit about 550 kilometers (340 miles) high. It is puny by world standards
...According to a pre-launch analysis by David Wright of the Union of Concerned Scientists, this kind of rocket might carry a small warhead to parts of Alaska, 6,000 kilometers (3,730 miles) from Pyongyang, but it could not hit Los Angeles, 9,570 kilometers (5,945 miles) away. Building that larger missile would require major advances in metallurgy, rocket engines, guidance and propulsion, and probably foreign assistance.
Second, North Korea would have to miniaturize its warhead. The primitive nuclear device tested by North Korea in 2006 is estimated to weigh more than 1,500 kilograms (3,307 pounds). That means North Korea's current nuclear weapons are simply too heavy to be launched by a vehicle similar to the one tested Sunday...