Missile Defense Review 2.0

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Note: This appears as Chapter 4 in Missile Defense and Defeat: Consideration for the New Policy Review.

Missile Defense Review 2.0

Henry A. Obering III

Since 2004, ballistic missile defense (BMD) has become a core competency of the U.S. military and a key element of our overall national security strategy. When discussing the future of ballistic missile defense, we cannot lose sight of this context. We should think of how it will integrate with our offensive capabilities both at the theater and strategic level to strengthen our deterrence posture. As we look to the future, there are several factors that must be considered in defining the next generation of capability. These include threat changes and technological advances. The decisions made today will shape the capabilities we will have tomorrow just like the capabilities we began fielding in 2004 were shaped by decisions made years earlier.

Inflection Point for U.S. Ballistic Missile Defense

The history of U.S. BMD has been defined by a series of inflection points since President Reagan launched the Strategic Defense Initiative in 1983. These milestones included technological breakthroughs as well as major policy shifts associated with threat changes.

The founding of the Strategic Defense Initiative Organization (SDIO) was the first major policy milestone with its concentration of funding and research across the Department of Defense directed at the development of capabilities to destroy incoming nuclear missiles. This resulted in significant technological advances in computer systems, component miniaturization, sensors, and propulsion systems that form the basis for our current ballistic missile defense elements.

Major technological milestones included the first intercept of an ICBM in 1984; the first space-based intercept, which occurred with the Delta 180 program in 1986; the development of smaller lightweight “hit-to-kill” interceptors in the 1990s; and the modification and development of powerful sea-based and land-based sensors in the 2000s.

Policy milestones included the movement from space-based to ground-based architectures in the late 1980s; the focus on Global Protection Against Limited Strikes (GPALS) by President George H.W. Bush in 1991; the shift to theater missile defense with the change to the Ballistic Missile Defense Organization (BMDO) by President Clinton in 1993; the withdrawal from the 1972 Anti-Ballistic Missile (ABM) Treaty and transition to the Missile Defense Agency by President George W. Bush in 2002 with the subsequent deployment of the first elements of an integrated, layered ballistic missile defense system (BMDS) to defend the U.S. homeland, allies, and friends against all ranges of missiles in all phases of flight; and the establishment of a European Phased Adaptive Approach (EPAA) in 2009 under President Obama with significant program cancellations/cutbacks and funding reductions.

As stated earlier, the factors that stimulated these inflection points included both threat status changes as well as technological advances. For example, the diminution of the Soviet threat and the Gulf War experience led President George H.W. Bush to shift to theater missile defense. The emergence of the missile threats from North Korea and Iran, along with the maturation of the intercept technology, were major factors in President George W. Bush’s ABM Treaty withdrawal and deployment decisions.

Today, these same threat and technological factors are at play, and with President Donald Trump’s administration we are now facing another major inflection point in the U.S. BMD program.

The Expanding Need for Ballistic Missile Defense

Ballistic missiles have been used in nearly every major conflict for the last three decades and are the “air force of choice” for many nations. In the Gulf War, a single Iraqi Scud missile attack was responsible for the largest loss of American lives in that conflict. Ballistic missiles were also used in Operation Iraqi Freedom, the Russian-Georgian conflict, as well as the ongoing war between Saudi Arabia and the Yemeni rebel forces. Despite decades of arms control measures, the proliferation of ballistic missiles continues to expand into more than 30 countries, many of which are hostile to U.S. interests.

North Korea

North Korea has an aggressive missile development program that includes short-, medium-, and long-range variants with eight that are either operational or presumed operational. In addition, it has demonstrated an ability to miniaturize a nuclear warhead, as evidenced by their test program. It has also successfully put satellites into orbit, thereby achieving the same technical know-how involved with the development of an intercontinental missile capability such as multistage flight, control through staging, and vernier thrusting. In addition, it has a submarine-launched missile in development.

The North Korean missile program was largely based on old Soviet Scud technology, elongating these missiles with larger propellant tanks for increased range (No Dong) and stack them for space launch capability (Taepodong). Its warhead construction also appeared to be rudimentary. For these reasons, the North Korean threat was described as “limited” and was one of the primary reasons for the deployment of today’s integrated ballistic missile defense system to address a “limited” threat. However, over the last several years, North Korea is advancing beyond what one could consider a “limited” threat. It has developed new propellant technology (hypergolic and solid) with new designs, and appears to be making progress in moving to even more sophisticated capabilities.


Similar to North Korea, Iran has also invested heavily in an aggressive ballistic missile program. With the largest missile inventory in the Middle East and short-, medium-, and long-range variants with eight either operational or presumed operational. Like North Korea, Iran too has achieved advances in propellant technology (Ashura) as well as the ability to successfully put satellites into earth orbit (Safir). The similarity between the Iranian and North Korean programs is unsurprising given the close cooperation in missile development between the two nations.

Iran has especially focused on improving the accuracy and lethality of its missiles. Accelerated advances can also be expected with the infusion of significant funding from the lifting of financial sanctions and the U.S. payment stemming from the Joint Comprehensive Plan of Action (JCPOA) agreement signed last year. Iran enjoys a close relationship with Russia and, as a result of the JPCOA agreement, has taken delivery from Russia of the advanced air and missile defense system known as the S-300.


One of the most compelling factors for an inflection point in the U.S. BMDS program is the reemergence of a belligerent Russia with the largest missile inventory in the world. Combined with its nuclear weapons program, Moscow presents an existential threat to the United States and its allies.

Russia has demonstrated advanced capabilities that would go well beyond the ability of the current U.S. BMDS to handle. These include advanced countermeasures to confuse sensors’ ability to discriminate warheads from decoys, the ability to maneuver and thereby complicate simple ballistic trajectory calculations for tracking, multiple independently targeted warheads per missile, and other means. Russia also has announced the development of advanced hypersonic missiles. Operating at speeds Mach 7 to Mach 12, these could penetrate today’s limited U.S. missile defenses.


While Russia has the largest inventory of missiles in the world, China has the most aggressive missile development program. This includes three different ICBM variants (DF-5, DF-31, DF41), maneuvering antiship missiles (DF-21) that pose a threat to U.S. carrier battle groups, and submarine-launched missiles (JL-2). Like Russia, China also has advanced countermeasures and an even more aggressive hypersonic program, having completed seven test flights of its DF-ZF missile.

What Do We Do First?

In light of these trends, what steps should we take to address these threats? We must strike a balance in improving the performance of the current system while developing the advanced capabilities needed for the future. The foundation for all of this is to increase the investment the United States makes in its missile defense program.

More Funding Needed for MDA

Since 2009, when President Obama took office, there have been dramatic cuts to the funding for the U.S. BMD program.

For example, in the last four years of the Bush administration, MDA spent roughly $40.7 billion. In the last four years of the Obama administration, MDA spent roughly $32 billion—a reduction of 21 percent. The funding cuts to the ability of the United States to defend its homeland have been even more drastic. The base budget for the Ground-based Midcourse Defense (GMD) program, the only element of the BMDS that can currently defend the U.S. homeland, has been reduced by over 60 percent since 2008. In addition, as systems are fielded, production, operations, and support costs are eating up more and more of MDA’s diminishing budget, which squeezes out the funding MDA can spend on its next generation of missile defense capability.

The United States should commit to funding MDA at a top line level of $12 billion per year in order to meet tomorrow’s threats, while addressing shortfalls with the current system. Budgetary responsibility for procurement and operations and support should be allocated to the responsible military service with money “fenced” from being used for other service priorities. Sustaining engineering responsibility and funding should remain with MDA to ensure we continue to build an integrated system.

Need for Homeland Defense Improvements

When the GMD system began deployment in 2004, the Exoatmospheric Kill Vehicle (EKV) contained in the Ground-based Interceptor (GBI) was an operational prototype. The decision to proceed with the deployment of a prototype was based on several factors: the United States had no homeland missile defense, the North Koreans were developing long-range missiles, the success of the GMD test program with four straight intercepts, and adherence to the National Missile Defense Act of 1999 that stated, “It is the policy of the United States to deploy as soon as is technologically possible an effective National Missile Defense system capable of defending the territory of the United States against limited ballistic missile attack.”

Modifications to the EKV to improve its reliability were developed and funding was programmed to achieve a full operational capability. With the cuts to the GMD program referenced earlier, however, these improvements were not fully implemented.

Redesigned Kill Vehicle

Starting last year, a new program to address the EKV reliability issue was initiated by MDA, the Redesigned Kill Vehicle (RKV) program. The technology in the current EKV fleet was developed in the 1990s. The RKV program allows the introduction of more modern technology to include advances in seeker capability, propulsion, guidance and control, manufacturing, and other improvements. The completion of the RKV program should be one of the first priorities to address the shortfalls of the current GMD capability. It should dramatically improve the effectiveness of the GMD system by reducing the number of interceptors fired at each incoming warhead. It should also include advances in communications technology to allow the kill vehicle to fully exploit all of the information available from the variety of space-based, sea-based, and land-based sensors.

Expand Current Capability

The current elements of the BMDS include:

  • Upgraded early warning radars in Alaska, California, Massachusetts, United Kingdom, and Greenland.
  • Deployed X-band radars in Japan, Turkey, Israel, CENTCOM, and a powerful and seabased radar ported in Hawaii.
  • Hundreds of deployed PAC-3 interceptors.
  • More than 100 sea-based SM-3 interceptors on over 30 Aegis BMD-capable ships.
  • 24 land-based SM-3 interceptors at the Aegis Ashore site in Romania with another site scheduled to be completed in Poland in 2018.
  • Terminal High Altitude Area Defense (THAAD) batteries with nearly 50 interceptors.
  • Approximately 36 silo-based GBIs in Alaska and California with a total of 44 scheduled for the end of 2017.
  • Operational command and control centers in Alaska, Colorado, Nebraska, Hawaii, Washington, D.C., and Germany.

The inventories of PAC-3, Aegis SM-3, and THAAD should continue to expand. With the delivery of the RKV, there would be merit in building a “third site” for 20 long-range interceptors on the East Coast. This would replace the capability lost with the cancellation of Phase 4 of the EPAA and could give the United States a “shoot-look-shoot” capability against Iranian launches.

Next-Generation Missile Defense

Whether we are addressing the rogue nation threat or stepping up to defend the nation from peer or near-peer threats, we must no longer think in terms of building just “limited” missile defense capabilities. The United States should begin the journey to develop a next generation missile defense that will form the foundation for our missile defense strategy well into the future. Several key future challenges include the ability to:

  • Provide “birth-to-death” tracking of incoming threat suites.
  • Intercept a single warhead in a complex threat suite including advanced countermeasures.
  • Intercept multiple warheads on a single missile.
  • Handle substantial raid sizes.
  • Intercept a missile in its boost phase from operationally effective ranges.
  • Provide reliable kill assessment.
  • Handle maneuvering warheads.
  • Destroy hypersonic missiles.
  • Operate in an aggressive, contested cyber domain.

The ability to build a next-generation missile defense is dependent on first meeting the nearterm challenges stated above. In order to go further, we need to pursue several key capabilities, including a precision tracking space-based sensor layer, advanced discrimination algorithms and techniques, a Multi-Object Kill Vehicle, boost phase directed energy, and a space-based kill layer.

Precision Tracking Space-Based Sensor Layer

We currently use space-based sensors to warn us of an adversary missile launch and then use the data to predict approximate impact points. These sensors do not, however, provide the accuracy needed to intercept the incoming warhead, so we rely on terrestrially based radars to provide missile tracks. The ability to provide persistent, “birth-to-death” missile tracking can only be done cost effectively from space, and doing so improves discrimination of the warhead from countermeasures and other objects.

Not only would a space-based tracking layer contribute to the defense of the U.S. homeland, the tracks would significantly expand the operating and defended areas of regional defenses. When integrated with terrestrial sensors, a space-based sensor layer would also contribute significantly to tracking more advanced threats, such as maneuvering hypersonics.

In 2009, MDA launched two Space Tracking and Surveillance System (STSS) demonstration satellites to determine the feasibility of providing intercept quality tracking from space. The results of the demonstration flights have been outstanding, and indicate that this capability is certainly achievable.

The United States should build an initial STSS constellation as a foundational capability. Further expansion and resilience could be added using more cost-effective and innovative approaches, such as putting payloads in commercial constellations and using other organizations’ satellites as hosts.

Advanced Discrimination Algorithms and Techniques

In 2006, MDA began developing advanced discrimination approaches that were suspended by the MDA director in 2010 in favor of another path that did not materialize. MDA has now revitalized these efforts, and they should be continued and fully implemented in their terrestrially based sensors.

In addition, there are several innovative contractor-developed approaches that significantly improve the ability of the BMDS to handle more complex threat suites. While outside the security scope of this paper, these efforts must be properly funded and deployed.

Multi-Object Kill Vehicles

No matter how much sensor discrimination capabilities are improved, they will never be foolproof. Therefore, the ability to destroy more than one “credible object” with a single interceptor is vitally important. These credible objects could include decoys, simulated warheads, debris, post-boost vehicles, and empty upper stages. In addition, having a multiple kill capability addresses those threat missiles with multiple real warheads.

A similar program called Multiple Kill Vehicle (MKV) was launched by MDA under President Bush, and later canceled under President Obama due to budgetary considerations. The value of such a capability was so compelling, however, that MDA established the Multi-Object Kill Vehicle (MOKV) program.

Each MOKV would have independently targetable kill vehicles that could be assigned to the credible objects. Each kill vehicle would steer itself to a target and destroy it. Modern communications technologies, algorithms, and processing power could significantly enhance the overall effectiveness of this “swarming” approach.

MOKV is a critical element of the next generation of missile defense. It will enhance nearly all aspects of the missile defense challenge, including discrimination, raid size, and kill assessment. MOKV capability could be provided to not only the GBIs but potentially also SM3 Block II interceptors. The effort should be given the highest priority in the interceptor development portfolio.

When MOKV capability is combined with the first two initiatives of precision space-based tracking and advanced discrimination algorithms, the system begins to be able to handle even the most advanced threat suites.

Boost Phase Directed Energy

The optimum approach to ensuring the warheads are destroyed in the presence of countermeasures is to destroy the enemy missile before it has a chance to deploy either the warheads or countermeasures. In other words, destroy the missile in the boost phase. Boost phase intercept provides advantages and disadvantages.

The advantage in destroying the missile in its boost phase includes the destruction of the warhead without having to deal with the countermeasures. In addition, most boost phase intercepts would place any residual intercept debris over the territory of the launching country.

The disadvantage is that the boost phase is typically short, so there is not time to launch a terrestrially based kinetic interceptor against many trajectories, especially against adversary countries that are geographically large.

Boost phase intercept is an ideal mission area for the use of a speed-of-light weapon such as a High Energy Laser (HEL). Using HELs against ballistic missiles is much more cost-effective than kinetic interceptors. Today, we have to fire multiple, multimillion dollar interceptors against a single threat missile. With a HEL, multiple threat missiles can be destroyed by a single laser magazine.

MDA experimented with just such a weapon, called the Airborne Laser (ABL), beginning in 2004 when it achieved first light and first flight of a megawatt-class HEL onboard a 747 aircraft. After successfully destroying both a solid propellant as well as liquid propellant missile in 2010 flight testing, the program was canceled due to budget constraints, as well as ongoing technical challenges.

Since the beginning of the ABL program in the 1990s, laser technology has come a long way. Today, there have been major advances in solid state and hybrid lasers. At least one version, the Diode Pumped Alkali Laser (DPAL), promises to deliver high-power capability in a weight and volume to allow it to be deployed on high-altitude unmanned aircraft. Operating in this regime and with a solid state or hybrid laser would avoid nearly all of the technical issues encountered by ABL.

It is now possible to have a lethal laser in the next 10 years capable of conducting the boost phase intercept mission from an airborne platform. MDA has submitted a report to Congress and is in the process of detailing their directed energy roadmap to achieve boost phase intercept. Since ABL, funding for directed energy activities at MDA has been very limited. This needs to change and sufficient funding should be provided to achieve their goals.

Space-based Kill Layer

To meet the missile threats presented by Russia and China, a move to a space-based kill capability is necessary. The geographies to be covered, the trajectories involved, and the complexity of the threat suites all lend themselves to a space-based kill approach.

Space is where missile defense began under President Reagan’s Strategic Defense Initiative. The advantage of the ultimate “high ground” allows global coverage even in large geographies, shoot-look-shoot capability for many trajectories, and more. In addition, a space-based kill capability can contribute significantly to overcoming the threat posed by hypersonic weapons.

This layer could initially consist of kinetic space-based interceptors (SBI) and later evolve to space-based lasers (SBL) as that technology matures. The SBI layer should complement terrestrially based assets, and even a modest constellation of satellites with several kill vehicles apiece could have a significant impact on the U.S. ability to defend itself against more advanced threats. It would expand the defended area to our allies around the globe as well, and could be used to support both regional and homeland defense.

As directed energy technologies continue to mature, and their size and weight continue to be reduced with increasing power levels, an SBL capability could then augment or replace the SBI capability. This space-based HEL capability with multiple kills per magazine could address substantial threat missile raid sizes.

To start down this path, the United States should fund the development of a space test bed to begin to explore the variety of technologies that could be brought to bear. This test bed could explore constellation command, control, communications and battle management issues; long-term storage of propellants on orbit; space-to-space engagement environments, and more.

Some critics will state that this type of defense from space is counter to existing treaties such as the Outer Space Treaty of 1967, but that is not the case. The only ban on weapons in space is that of weapons of mass destruction, which obviously does not apply to either SBI or SBL.

The Cost vs. Benefit of Ballistic Missile Defense

With the dramatic decline in the defense budget due to budget caps since the 2011 Budget Control Act, there has been a major focus on the cost of our weapon systems and less emphasis on their value.

Is building the next-generation missile defense worth the costs?

To answer this, the costs of missile defense must be put in perspective. The total spending on the U.S. BMD program from 1985 through 2016 has been approximately $235 billion in inflation-adjusted dollars.

How does one measure the value of this investment? One way to approach this is to look at the 9/11 attacks on New York City and Washington, D.C. The physical damage to NYC alone from the September 11 attacks, according to a 2002 Government Accountability Office study, was $83 billion.1

The total economic cost from both attacks was $3.3 trillion and these attacks did not involve a nuclear weapon, which would have caused more destruction by orders of magnitude.2

Even at $12 billion a year, the investment in ballistic missile defense pays for itself many times over.

Final Considerations

Developing next-generation capabilities would also have several broader national security advantages.

First, building a robust missile defense system could dissuade adversaries from developing ballistic missiles in the first place, since their effectiveness would not be clear.

Second, without the protection of a robust missile defense, some nations capable of building their own nuclear weapons for defense might be incentivized to do so. This would lead to further instability in regions such as the Middle East and the Asia-Pacific.

Third, a robust missile defense capability enhances deterrence by putting doubt in the mind of an attacker. Not knowing which of the offensive missiles would survive complicates an attacker’s plan.

Fourth, missile defense can stabilize events in a crisis. For example, in 2006 when North Korea was preparing to launch the multistage Taepodong-2 (TD-2) missile and not providing any international notification as required by protocol, several senior former DoD officials called for a preemptive strike against the launch site, which would have been highly escalatory. President Bush decided to rely on the GMD system should the TD-2 missile threaten U.S. territory.

Fifth, missile defense provides the president and other senior commanders an option other than preemption or retaliation, and provides critical additional decision time when faced with an accidental or rogue-directed launch

Finally, and most importantly, if deterrence fails, it is the only option available to destroy warheads once they are launched.


The United States has made tremendous progress to meet a real threat that is only going to grow—in spite of our efforts otherwise. And as has often been the case in the history of ballistic missile defense, we are at an inflection point.

Today we are developing and fielding missile defenses to meet a “limited” threat from countries like North Korea and Iran. But even the threat from the rogue nations is now progressing beyond the “limited” level.

We must use this inflection point to build the next generation of missile defense needed, not only to meet the rogue nation threat, but also the threats posed by Russia and China as well. The decline in funding for these defenses must be reversed and restructured so that MDA can once again focus on building tomorrow’s capabilities.

The technology continues to mature and improve to allow several game-changing measures to be pursued such as directed energy and space-based capabilities.

This is too important not to get it right.


    1. Government Accountability Office (GAO), Review of Studies of the Economic Impact of September 11, 2001, Terrorist Attacks on the World Trade Center (Washington, DC: GAO, 2002), http://www.gao.gov/new.items/d02700r.pdf.
    2. David Sanger, “The Price of Lost Chances,” New York Times, September 8, 2011, http://www.nytimes.com/2011/09/08/us/sept-11-reckoning/cost.html.
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Missile Defense Project, "Missile Defense Review 2.0," Missile Threat, Center for Strategic and International Studies, March 1, 2017, last modified April 28, 2021, https://missilethreat.csis.org/missile-defense-review-2-0/.