In this Oct. 16, 2016, file photo, a man watches a TV news program showing a file image of a missile launch conducted by North Korea, at the Seoul Railway Station in Seoul, South Korea.

In this Oct. 16, 2016, file photo, a man watches a TV news program showing a file image of a missile launch conducted by North Korea, at the Seoul Railway Station in Seoul, South Korea. AP /ANN YOUNG JOON

The Technology Race to Build — or Stop — North Korea’s Nuclear Missiles

As Pyongyang warns of an upcoming ICBM test, and Trump threatens to stop it, the Pentagon has few good options.

North Korean officials recently announced that the country was on the verge of testing a nuclear-tipped intercontinental ballistic missile, or ICBM, that could reach the United States. President-elect Donald Trump drew a line in the sand. “Won’t happen,” he said on Twitter. If North Korea attempts to test an ICBM, the United States has a number of options to stop it. All carry risks.

Trump’s red line mirrored past statements from policymakers. Ten years ago, future Defense Secretary Ash Carter and former Defense Secretary William Perry wrote, “Should the United States allow a country [North Korea] openly hostile to it and armed with nuclear weapons to perfect an intercontinental ballistic missile capable of delivering nuclear weapons to U.S. soil? We believe not.”

How close is North Korea to an actual nuclear ballistic missile and what are the president’s military and policy options? Let’s take a look.

North Korea is researching a variety of missiles that with research and development could be converted into ICBMs. In February, North Korea launched a satellite into orbit aboard its 28-meter, three-stage Unha rocket.

“Several U.S. four-star commanders have said North Korea has, or we must assume they have, the ability to reach the continental U.S. with a nuclear warhead with the Taepo Dong (Unha) missile,” said Bruce Klinger, an analyst with the conservative Heritage Foundation think tank. The Unha has a range of 10,000 kilometers, sufficient to hit the United States. Klinger argues that the range might be closer to 13,000 kilometers, enough to reach the East Coast.

But shooting a satellite into space is a different feat of physics than demonstrating an ICBM, which must re-enter the earth’s atmosphere along a controlled and precise trajectory to its target.

“The Unha-2 or -3 could serve as a springboard for the development of an ICBM, but the history of long-range missile development by other countries, including the Soviet Union, the United States, China, and France, indicates that satellite launch activities have limited impact on missile programs. No country has converted a satellite launch rocket into a long-range ballistic missile,” according to Michael Elleman and Emily Werk of the Arms Control Association.

A more likely candidate for a near-term ICBM test is the 16-meter-long KN-08 ballistic missile. It can be launched via a truck platform, making it harder to hit with a pre-emptive strike. It currently has a documented range of about 6,700 km, due to fuel limitations. In April 2016, North Korea unveiled photos of an engine test that purported to show a new rocket engine capable, potentially, of sending a nuclear warhead to the United States.

“Using this technology, North Korea’s road-mobile intercontinental ballistic missile (ICBM), the KN-08 or the KN-14 modification, 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 U.S. east coast, including New York or Washington,” John Schelling wrote in April on the blog of the Johns Hopkins School of Advanced International Studies. “If the current ground test program continues and is successful, flight tests of a North Korean ICBM could begin in as little as a year. Moreover, Pyongyang may be able to deploy this delivery system in a limited operational capability by 2020.”

The second component needed for a nuclear missile is a miniaturized warhead. On Tuesday, State Department spokesman John Kirby said the U.S. does not believe that North Korea has a weapon small enough to fit atop ICBM. But that may be little more than a temporary state of affairs.

At a Defense One event in November, Adm. Harry Harris, commander of U.S. Pacific Command, said, “I have to assume that they have it...I believe it when Kim Jong Un expresses his intent.”

Counter Strategies

So how do you make sure the test “won’t happen?” On the one hand, you could launch a coordinated airstrike, sending jets or bombers over North Korea to destroy the missile on the launch pad as it is about to take off. But that carries risks of triggering a rocket retaliation against South Korea, risking massive casualties.

“The reason why the U.S. didn't do what Carter and Perry had suggested [in 2006] of course, was we were concerned that if we did that, North Korea would probably shell Seoul with artillery. That was an unacceptable escalation,” said RAND Corporation's Bruce Bennett.

Once an ICBM is launched, here are the options to stop it. To protect the continental U.S., the United States has 30 ground-based interceptor missiles in Fort Greely, Alaska, and Vandenberg Air Force Base, Calif. 

The United States is working to deploy other anti-missile systems, such as the Terminal High Altitude Area Defense, or THAAD system, but those are designed to intercept shorter-ranged missiles.

The “THAAD battery is designed to intercept their medium-range missiles like the No-dong missile and the Musudan missile, if fired at South Korea. The THAAD missiles have a range of only 200 kilometers, and that battery would be put close to Busan, so they can't even really cover Seoul with that battery, let alone something flying out over the Pacific,” said Bennett. South Korea long has expressed interest in an anti-rocket defense system similar to Israel’s Iron Dome, but has not bought that system or fielded such protection.

The United States also has Aegis BMD-equipped ships in the Pacific armed with Standard missiles capable of intercepting medium-range ballistic missiles. But “these aren't designed for intercontinental-range missiles,” said one Defense Department official. The Aegis system is designed primarily to protect ships, not shoot down ICBMs.

“Some of these ships are based in Europe as part of a NATO missile defense system. Some of them are based in the Pacific as part of a defense system for our allies. There's also a terminal defense system in Guam that's designed to defend Guam. These things exist; there are capabilities. But for an ICBM, obviously the major concern of an ICBM is defending against a sufficiently long-range threat, which would be the homeland, right? You wouldn't use an ICBM if you were North Korea trying to attack Japan, it's too close, doesn't make any sense,” said the official.

It may make sense from a resource perspective, but does show Trump’s red line to be difficult to enforce.

Kill It With Lasers

The military has shown that it can take down ballistic missiles with laser-armed planes, going back to 1983. Today, the Missile Defense Agency is researching new methods for stopping an ICBM before it hits the air. Lasers are still the most attractive option. “One of the options available to us that we are going to start testing here in the next couple years is a laser aboard a unmanned vehicle, [or drone] something that has some level of persistence that can be in the area and could engage when the missile is at its most easily targetable, but that's some ways off,” said the official, referring to the low power laser demonstrator program.

The program follows the airborne laser program, or ABL. “We have proven that capability, so now the idea is if we can make it small enough and powerful enough and have a UAV with sufficient dwell capability, we would be able to keep them in some numbers over an area,” said the official.

Unlike ABL, the low-power demonstrator would use a safer, more energy-saving solid state laser rather than a chemical laser.

A laser-armed drone flying over North Korea could easier to deploy than an airstrike, and damage could be limited to the missile itself. And it still risks North Korean retaliation against U.S. allies in the region. Until then, the United States has a number of non-violent policy responses.

“There is still much that can be done against North Korea and, through third-party sanctions, foreign entities that facilitate North Korea’s prohibited programs,” said Klinger. “Rather than initiating an attack on North Korea for crossing yet another technological threshold, it would be more prudent to reserve a preemptive attack for when the Intelligence Community has strong evidence of imminent strategic nuclear attack on the U.S. or its allies. Similarly, a lone North Korean missile on a test flight aimed only at open water does not pose an imminent or existential threat to the United States. Intercepting such a flight, as some have advocated, would redirect international focus and anger away from another North Korean violation of UN resolutions and instead to the U.S. military action.”