While North Korea is maintaining its torrid pace of weapons tests, there are at least three key hurdles Kim Jong Un’s regime still needs to overcome before it can field a nuclear-tipped intercontinental ballistic missile capable of threatening the U.S. mainland.
The threat from Pyongyang is growing, but it isn’t yet imminent, according to General Paul Selva, the No. 2 U.S. military official. Selva, vice chairman of the Joint Chiefs of Staff, offered his thoughts in a statement to Bloomberg before North Korea launched an intermediate-range missile early Tuesday local time over Japan.
“It is clear North Korea has the capability to build a missile that can range the distance to the United States, but North Korea has yet to demonstrate it has the requisite technology and capability to actually target and strike the United States with a nuclear weapon,” Selva said in his statement.
First, North Korea would have to deploy a guidance and stability control system that could direct a long-range missile thousands of kilometers accurately without breaking apart, Selva said. Second, it needs a reentry vehicle housing the warhead that can survive the heat and stresses of an intercontinental ballistic launch. Third, it needs a nuclear weapon “that is small enough and stable enough to survive the trip,” he said.
Read a QuickTake Q&A on what U.S.-North Korea hostilities might look like
“We don’t know how fast Kim Jong Un can accelerate the development of those technologies, but we’re certainly paying attention to determine what tools we have to either deter or slow his advance,” Selva said, echoing comments he made on Capitol Hill earlier this month.
Improvements in North Korea’s missile program following an unprecedented pace of launches this year — more than 20 since January — fueled tensions with the U.S. that peaked when Kim’s regime said it might direct missiles toward the waters around Guam. That prompted President Donald Trump to warn of “fire and fury” from the skies if Pyongyang went forward with its plans.
“Recent North Korean tests of missiles capable of reaching intercontinental range clearly demonstrate progress in and continued commitment to their ICBM program,” James Kudla, a Defense Intelligence Agency spokesman, said via email Wednesday. “If left on its current trajectory, the North Korean regime will ultimately succeed in fielding a nuclear armed missile capable of threatening the U.S. homeland.”
Relations between the U.S. and North Korea briefly eased after Trump’s “fire and fury” comment. Secretary of State Rex Tillerson said Sunday that despite North Korea’s “provocative” firing of three short-range missiles last week, the U.S. will continue to push for negotiations to de-escalate nuclear tensions on the Korean peninsula.
But the Trump administration delivered mixed signals in the following days, with the president dismissing the idea of negotiating with Kim’s regime and his defense chief saying the U.S. hasn’t yet exhausted its diplomatic options.
There’s no suggestion in Selva’s remarks that the technology gap facing North Korea is beyond reach given the country’s recent improvements in rocket technology. But several outside analysts agreed with his assessment about the barriers that remain.
“I believe that it will take Pyongyang several more years to seriously threaten the U.S. with nuclear-tipped missiles,” said Siegfried Hecker, a former Los Alamos National Laboratory director and nuclear expert who’s visited North Korea seven times.
“Testing a missile booster and a reentry vehicle is a long way from having an actual operational missile,” Anthony Cordesman, an analyst at the Center for Strategic and International Studies in Washington, wrote Aug. 15.
That was the official view even before the most recent ICBM tests. One week before North Korea’s first ICBM launch last month, Scott Bray, the national intelligence manager for East Asia at the Office of the Director of National Intelligence, said in a speech that delivery of a viable North Korean weapon “requires an ability to launch a heavy missile and re-entry vehicle capable of surviving the stresses of atmospheric re-entry. These are difficult engineering challenges.”
The U.S. should take advantage of North Korea’s as-yet incomplete capability in its diplomatic efforts, said Robert Litwak, a former National Security Council counter-proliferation director and director for international affairs at the Woodrow Wilson Center in Washington.
“If what is driving the crisis from the U.S. perspective is our imminent vulnerability to a long-range ballistic missile strike with a nuclear warhead and there is a critical component of this complex integrated system that North Korea has yet to master — reentry — that may create space for diplomacy” to push a test freeze, Litwak said in an email.
The aim of a test freeze would be “to preclude the additional testing that” the North Koreans would need to perfect the capability, he said. It’s a “long-shot but worth pursuing.”
Straight Into Space
Assessments of North Korea’s ability to strike the U.S. mainland are theoretical and based on the “physics and modeling” of the trajectories of the two missiles tested in July, according to Steven Hildreth, a missile defense analyst with the non-partisan Congressional Research Service said in an email. Those missiles were essentially lofted straight into space, not outward toward another country.
Missile accuracy can only be established “through full-range or nearly full-range flight tests, not lofted trajectories,” said Michael Elleman, a North Korea missile expert with the International Institute for Strategic Studies.
To be sure, “this might not be a tremendous issue” for North Korea because “I believe that they are more concerned about having the ability to reach the United States” rather than actually being able to target a specific city or military installation, said Joe Bermudez, an analyst with 38 North, a website that monitors North Korea.
North Korean Capabilities
To get that far, however, North Korea will have to tame pressures including the tremendous vibrations and associated heat build up generated during launch as well as negative gravitational forces — like being pulled forward in your airline seat — and then rapid cooling, more vibration and more heat build-up on reentry, he said.
It’s within North Korea’s capability to produce a viable warhead but “unclear if the political system will facilitate or hinder” development “and if it does permit it, how long will it take them to do so, as they haven’t demonstrated it yet,” Bermudez said.
David Wright, a scientist with the Union of Concerned Scientists, doesn’t see any “fundamental problems” with North Korea eventually developing a working reentry vehicle if it hasn’t already but “the U.S. probably doesn’t have a way of knowing this for sure.”
Even if some tests fail “the North Koreans will figure” out a way to overcome the challenges, Jeff Lewis, director of East Asia nonproliferation at the Middlebury Institute of International Studies in Monterey, California, said in an email.
— With assistance by Ben Brody