As the North Korean government continues its ballistic-missile testing, a chorus of voices insist that the United States has “no good options” for addressing this growing threat. With China unwilling or unable to reign in Kim Jong-un and a U.S. preemptive first strike likely to start a devastating war, we are told that the United States must now acquiesce to a nuclear armed North Korea. Strategic patience must now yield to permanent acceptance. Many analysts have assumed that the U.S. has only three basic options for addressing the North Korean threat: an offensive first strike, diplomatic initiatives involving China and sanctions, or acquiescence. But the United States has other options that do not require either starting a war, waiting for help from the unwilling, or accepting the vulnerability of U.S. and allied cities to a North Korean missile attack. Rather than initiating a military strike or continuing to pursue ineffective diplomatic initiatives, the United States can take advantage of recent technological advances to deploy a more effective multi-layered missile defense, including one system perfectly suited to defuse the North Korean crisis.
Vulnerability to Ballistic Missiles
The American ability to project power abroad through its conventional forces — carrier groups, fighter and bomber squadrons, cruise missiles, ground troops, and special forces — remains unrivaled despite sequester-driven budget cuts and the erosion of capability they have caused. Nevertheless, at home American cities stand vulnerable to attack by intercontinental ballistic missiles (ICBMs) as well as shorter-range missiles launched from submarines or even small ships offshore.
Though North Korea has not yet definitively demonstrated the ability to track and deliver ICBMs on target, the Defense Intelligence Agency now believes that Kim Jong-un has the capability to miniaturize a nuclear device and place it inside an ICBM. Once Kim also acquires more precise targeting capability, cities across the western United States will be vulnerable to his missiles and the president to his nuclear blackmail. Indeed, current ground-based missile-defense systems, though necessary, are not sufficient to protect U.S. cities from the first-strike capability of several potential adversaries, including soon North Korea. The Terminal High Altitude Area Defense system (THAAD) and Aegis ship-based missile-defense systems have demonstrated an impressive accuracy in defending against short-and medium-range missiles of the kind that North Korea could fire at South Korea or Japan. Nevertheless, these ground-based systems cannot stop Chinese, Russian, or North Korean intercontinental ballistic missiles from hitting U.S. cities. Russia alone has 1500 sophisticated ICBMs, more than enough to overwhelm the several dozen existing and unreliable ground-based interceptors in Alaska and California.
The Boost Phase Intercept
Consequently, the United States urgently needs to develop and deploy higher altitude and space-based systems for missile defense. Arthur Herman of the Hudson Institute has taken the lead on advocating one such high-altitude system with particular promise for neutralizing the North Korean threat. Known as High Altitude Long Endurance Boost Phase Intercept (or HALE BPI), this system would offer another option besides acquiescence or a high-risk first strike against North Korean missile launchers. As conceived by Len Caveny, the former director of science and technology at the Ballistic Missile Defense Organization, the HALE BPI system would host anti-missile missiles on existing unmanned aerial vehicles (UAVs) that have the capacity for continuous flying for 18 to 40 hours or more (thus, the term “long endurance” in the HALE acronym). Using sophisticated radar, infrared detection, and “data fusion” technology, these missile-equipped UAVs would circle the Sea of Japan outside North Korean airspace at an altitude of 45,000 feet or more. Upon detection and verification of a missile launch from North Korea, the HALE BPI UAV’s operator on the ground would have time (perhaps a minute or more) to fire a purely kinetic missile, i.e. a missile without an explosive warhead, at the missile in its “boost phase.” Using already existing guidance systems and the pure kinetic energy that can be generated by even a small object moving at an extremely rapid velocity, the missile would destroy a North Korea missile almost as soon as it leaves the launch pad.
At a recent conference hosted by the Hudson Institute and General Atomics in San Diego, Caveny explained that most of the modular technological elements of such a system already exist and that an effective kinetic BPI system could be developed and deployed in two years, or within 12 months if the development of the system were put on an expedited war-prevention footing. Herman, in a series of compelling op-eds and position papers, has argued that such a system offers many benefits for addressing the North Korean crisis and multiple advantages over existing ground-based missile-defense systems that attempt to destroy missiles during their downward “terminal phase” of flight.
First, rising missiles in their boost phase are easiest to detect and destroy. During boost phase, missiles are moving at their slowest velocity, making them easier to shoot down. They also burn more fuel at this point in their trajectory, giving them their hottest infrared signature and making them easier to detect at long range. In addition, missiles in boost phase cannot employ evasive maneuvers or deploy multiple independently targetable reentry vehicles (or MIRVs) — unlike descending ICBMs in terminal phase.
Second, destroying missiles in the boost phase ensures that the debris from the kinetic collision and destruction of the warhead will fall safely over the Sea of Japan or even on North Korean territory, a poetically just way of enhancing deterrence and effectively boxing Kim Jong-un’s threat into a confined airspace.
Third, the BPI system currently envisioned by Herman and Caveny would represent only a near-horizon defensive weapon system — one that would not directly threaten the nuclear deterrent of the Chinese. Hosting a boost phase system on a UAV rather than in space would not, therefore, protect against ICBMs launched from countries with large land masses such as China and Russia. Nevertheless, in the immediate context of the North Korean crisis, such a system would have the advantage of representing a defensive response to a clear provocation. As such, it should not antagonize the Chinese, precisely because it does not compromise their own nuclear deterrence (or offensive capability). Even so, its deployment, like that of the THAAD system, will clearly not please the Chinese. But given that they cannot reasonably object to such a purely defensive system, especially in the current crisis, their displeasure could incentivize them to distance themselves from North Korea or even to pressure their client state to stop further testing of nuclear weapons.
Fourth, the HALE BPI’s altitude and the speed of its interceptor missile (3.5 to 3.7 km/second), in addition to its advanced digital signal-processing and data-fusion technology, allows its operators on the ground a minute or more to decide whether a rising object over North Korea has a trajectory that indicates a ballistic missile on a dangerous course. In this context, a full minute represents an eternity and could prevent an unnecessarily provocative response from the United States and its allies to a “false positive,” and time to decide that the missile’s trajectory indeed represents a threat and must be destroyed. Fifth, since most of the technology for building a high-altitude kinetic BPI system already exists, it can be built inexpensively as well as quickly. Caveny and Herman estimate that such a system could now be built for tens of millions, not billions, of dollars — pocket change for the Department of Defense, with its annual $639 billion budget. Indeed, $25 million or less (Caveny’s best estimate of cost) even represents a small portion of $8 billion budget of the Missile Defense Agency.
Finally, deploying a high-altitude kinetic BPI could contribute to a comprehensive plan for protecting the U.S. power grid against a nuclear electromagnetic pulse attack, something that Kim has now threatened. Since the 1960s, nuclear engineers and physicists have worried that the detonation of a nuclear device in the upper atmosphere (between 100 to 150 kilometers above the earth) could produce a shock wave of potentially destructive electromagnetic energy that spreads spherically in concentric waves through the lower atmosphere over many hundreds of miles. Such a blast could destroy sensitive electronic equipment, including critical components of the electrical-power grid, such as transformers, generators, computer control (SCADA) systems, relays, and switches. Nevertheless, since producing an EMP effect would require detonation at high altitude, an EMP attack necessarily requires launching a ballistic missile (or satellite). For this reason, an effective missile-defense system that can prevent missiles from reaching altitude over North America would provide a layer of protection for critical infrastructure against the possibility of an EMP attack, especially one from inaccurate short-range missiles launched from a submarine or ship (possibly flying a false flag to evade retaliation). Consequently, the proposal of Hank Cooper, former director of the Strategic Defense Initiative, to deploy a curtain of reconfigured ballistic-missile-defense-capable Aegis ships in the Gulf of Mexico to shore up a potentially vulnerable southern exposure warrants urgent attention. Similarly, expediting development of the HALE BPI system, and deploying it along U.S. coastal exposures as well as near the Korean peninsula, could play a critical role in protecting of the U.S. power grid from missiles launched either from off shore or from North Korea.
The Promise of Space-Based Missile Defense
Of course, to provide protection from Russian and Chinese ICBMs, the United States will need more comprehensive space-based missile defense. Indeed, kinetic boost-phase systems hosted on high-altitude vehicles will not prevent missile launches from countries such as Russian and China, with vast expanses of land far from international airspace. Even so, the rapid deployment of a high-altitude kinetic BPI system would take an important first step toward a longer-term effort at building a more comprehensive multi-layered ballistic-missile defense, including both kinetic and laser space-based systems. Lessons learned from the development and deployment of high-altitude missile-defense systems will expedite the development and deployment of space-based systems, especially those using kinetic weapons. And only space-based and high-altitude systems can reverse the cost advantage that offensive countermeasures have long held over existing more expensive land-based missile interceptors.
Fortunately, the technology for developing a purely kinetic space-based system — the so-called Brilliant Pebbles system — has been available since the early 1990s. As conceived by the engineers who developed Strategic Defense Initiative technologies, the Brilliant Pebbles system would have deployed about 2.000 watermelon-sized all-in-one orbiting interceptors with sensors, guidance, and propulsion systems on board. Once a “Brilliant Pebble” satellite detects a missile nearing its apogee or mid-course, on-board boosters and guidance systems would accelerate the whole projectile toward the rising missile and destroy it without an explosive warhead, again, using the pure kinetic energy generated by the rapid acceleration of the interceptor. Though the system passed all its initial proof-of-concept testing, the Clinton administration terminated the program in 1994, part of a larger post–Cold War effort to recoup a “peace dividend.”
During the early 1990s, engineers working for the Strategic Defense Initiative Organization (SDIO) estimated that 2,000 space-based interceptors would have cost about $1.6 billion (roughly $3 billion today) to build and deploy at $800,000 per interceptor. This suggests — even making generous allowance for inflation, retooling and greater bureaucratic inefficiency — that such a system could be built for less than $10 billion over the next several years. Engineers familiar with the system estimate that it would take two years to build and test the Brilliant Pebbles satellite interceptors and two more to deploy the whole system in space.
Space-based missile defense systems will cost more than a HALE BPI system, but the development of these systems should be a top defense priority as well. The United States spends roughly $8 billion per year on land- and sea-based systems insufficient for the defense of U.S. cities against ICBM attack. Even so, current spending on missile defense accounts for barely over 1 percent of the $639 billion U.S. defense budget. Yet, arguably, the American homeland is more vulnerable to ballistic-missile attack than any other kind of threat. A robust, kinetic space-based missile-defense system — built for less than $2.5 billion per year over four years — could be deployed during the first term of Donald Trump’s presidency, a small price to pay to address the country’s most urgent security vulnerability. Laser space-based systems can follow over a longer term as technology advances.
In 1983, at the height of the Cold War, President Reagan outlined his vision for making ballistic missiles obsolete with his Strategic Defense Initiative. Though Russian defectors later confirmed that the mere threat of a space-based missile defense convinced the leaders of the Soviet Union that they could not win an arms race with the United States, successive presidents never actually built the multi-layered missile defense that Reagan envisioned. Consequently, the American people remain unprotected from the threat of attack from ballistic missiles with nuclear warheads, including — soon — those under the control of a rogue North Korean despot.
Nevertheless, the vulnerability of American cities to ballistic missiles (North Korean and others) need not continue. The United States has the technology and knowledge to build effective missile defense, including a boost-phase system that can neutralize the current North Korean missile threat by preventing missiles from leaving (or ranging far from) North Korean air-space. Building such a system on an expedited war-prevention footing will massively alter the psychological dynamics of the current crisis because it will eliminate the need for ever greater demonstrations of military force and resolve — demonstrations that could themselves provoke a response and an uncontrollable escalation.
Instead, quietly building an effective high-altitude defensive system, in tandem with efforts to enhance offensive capability and deterrence, will permit President Trump to exercise the right kind of strategic patience. Just as President Reagan avoided direct confrontation with the Soviet Union in the early part of his presidency in order first to rebuild the American military (and to allow his military planners to develop the SDI concept), Mr. Trump should avoid risking a direct confrontation with North Korea until the Air Force has deployed a defensive missile system that can render obsolete the weapons that have precipitated the current crisis. In the process of developing such a system, the United States will find itself much closer to deploying a space-based system that can protect its cities against all such missiles. Viewed in this light, the North Korean crisis creates an opportunity — as well as a compelling justification — for President Trump to do what President Reagan’s successors failed to do, namely, to make the American people safe from the real threat of nuclear-tipped ballistic missiles.