North Korea has successfully tested and redesigned many of the components necessary for a nuclear-tipped ICBM capable of reaching the US mainland, i.e., ballistic missile, reentry vehicle, and miniature nuclear warhead.
Joel Wit of the U.S.-Korea Institute at Johns Hopkins University asserts: “Last year, researchers at the institute where I work concluded that by 2020 North Korea could field an intercontinental ballistic missile able to reach the United States. But if Pyongyang tests the missile that has appeared in recent military parades, it could be sooner. The simple hydrogen bomb the North Koreans were expected to have by 2020 now may be ready and mounted on a missile earlier.”
The Unha rockets used to launch North Korea’s satellites into space are based on a Taepodong long-range ballistic missile that has an estimated flight of 5,600 to 9,000 kilometers—the distance to San Francisco. The larger Unha-3 has a maximum range of 13,000 km, which endangers the entire US mainland; the distance between North Korean launch sites and New York or Washington D.C. is about 11,000 km.
Many analysts believe satellite rocket launches are veiled ICBM tests and allow North Korea to test a reentry vehicle without admitting it is part of a missile. Musudan missile launches also test this capability. Former Lockheed Martin research scientist and missile expert Michael Elleman asserts: “American efforts to deter and prevent North Korea from flight testing the KN-08, Musudan or other long-range ballistic missile must take priority over unwelcomed satellite launches using the Unha or equivalent rockets.”
The smaller KN-08 ballistic missile (still untested) also has a potential range to strike anywhere in the continental US. Senior aerospace engineer John Shilling contends that new high-energy propulsion units “could deliver a nuclear warhead to targets at a distance of 10,000 to 13,000 km. That range, greater than had previously been expected, could allow Pyongyang to reach targets on the US east coast, including New York or Washington, DC.”
In December 2015 John Shilling asserted that North Korea has not demonstrated the ability to build a reentry vehicle that can survive the heat of atmospheric reentry at 7 km/s: “If and when they do, what is presently a theoretical threat will become very real and alarming.” Three recent successful launches of Musudan missiles may have provided test data for a reentry vehicle. Thus, in June 2016 Schilling upgraded his assessment: “The North Koreans probably now know, for the first time, what happens when one of their warheads enters the atmosphere at roughly 10,000 miles per hour.”
Since 2013, the South Korea Defense Intelligence Agency has contended with “moderate confidence” that North Korea is capable of miniaturizing nuclear weapons. In early 2015, North Korea claimed it had succeeded in miniaturizing a warhead, while at about the same time Jeffrey Lewis of the Monterey Institute of International Studies asserted: “It seems very plausible to me that, after three tests, the North Koreans have a nuclear weapons design somewhere in the Mark 12 to March 7 range—450-750 kg in mass with a diameter between 60-90 cm.” Lewis contends such a warhead is small enough to arm a Nodong IRBM and might just fit on an ICBM.
That the US and South Korea do not have intelligence that North Korea has succeeded in fitting nuclear warheads on ballistic missiles does not mean it isn’t so. Pakistan may have accomplished this in less than a decade, perhaps in less than 5 years.
When I asked Stanford nuclear expert Sigfreid Hecker why in a published report he said it would take North Korea ten years to be able to land a nuclear-tipped ICBM on the US mainland he told me “No one is sure whether or not it could take 5 or 10 years.” But one thing seems certain; at some time in the not too distant future, an unstable autocratic North Korea with a GDP the size of Togo and Swaziland will have the capability to kill millions of US citizens at the push of a button from the opposite side of the globe.