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Understanding Delivery Systems Threats

  • Understanding the Delivery Systems Threat

    A country’s delivery systems determine how, when, and against whom it can use its conventional, nuclear, chemical, or biological weapons. Countries or non-state actors could potentially use low-technology methods (such as artillery, or even a boat or truck) to deliver WMD, but more advanced systems such as cruise missiles, ballistic missiles, and combat aircraft provide greater speed, reliability, survivability, range, and control. While early in the missile age only countries with major industrial capabilities and significant defense budgets could afford missile programs, more than 30 countries are now capable of domestically producing ballistic or cruise missiles. Additionally, countries such as North Korea and Iran have more limited programs able to supply critical technologies to countries seeking missiles. Despite the dangers of the continued proliferation of advanced delivery systems, no binding international nonproliferation treaty controls the spread of missiles or other delivery systems.

  • What is a Ballistic Missile?

    A ballistic missile is a missile system that follows a ballistic, sub-orbital flight path on the way to its target. It is propelled by a chemical rocket engine, using either liquid or solid fuel.  Ballistic missiles travel thousands of miles in a matter of minutes, and are difficult to defend against.  Ballistic missiles are divided into four categories, depending on their range: Intercontinental ballistic missiles (ICBM) with a range of over 5,500 km; intermediate-range ballistic missiles (IRBM) with a range of 3,000 to 5,500 km; medium-range ballistic missiles (MRBM) with a range of 1,000 to 3,000 km; and short-range ballistic missiles (SRBM) with a range of less than 1,000 km. Despite the significant costs involved in developing and maintaining an arsenal, ballistic missiles require fewer resources and training than manned aircraft once deployed, and thus offer an attractive option for striking at far away enemies with little warning.  Deployable in silos, on road-mobile launchers, and on submarines, ballistic missiles of varying ranges have proliferated to countries in every region of the world.

  • Intercontinental Ballistic Missiles

    Only Chinese, Russian, American, French, and British forces now possess confirmed intercontinental ballistic missile (ICBM) strike capabilities, while the development of such systems is possibly underway in India, Iran, Israel, North Korea, and Pakistan.  ICBMs debuted in the Soviet Union during the Cold War, with American deployments following soon thereafter.  Initially designed to carry nuclear weapons between the Soviet Union and the United States, the most advanced ICBMs can carry payloads of several megatons. Multiple-independently targetable reentry vehicle (MIRV) technology also allows for several warheads to be placed on a single ICBM.  The high speeds at which ICBMs travel make them poorly suited for chemical and biological weapons.

  • Theatre Ballistic Missiles: Regional Delivery Systems, Possible Pathways to ICBMs

    Ballistic missiles with a range of less than 5,500 km (IRBMs, MRBMs and SRBMs) are also known as theatre ballistic missiles, and often carry smaller payloads than ICBMs. Some countries may use them as stepping stones on the path to developing ICBMs, as countries generally start by building shorter-range ballistic missiles and incrementally improving range over time. Conventionally-tipped theatre ballistic missiles offer greater utility in regional conflicts, such as in South Asia, Northeast Asia, and the Middle East. However, their utility is greatly constrained by their often highly imprecise guidance systems. More widely traded in than ICBMs, the export of Soviet Scud-B missiles in the 1970s and 1980s facilitated the worldwide spread of ballistic missile technology. Several countries, including North Korea, Iraq, and Egypt, reverse-engineered imported Scud-B missiles as the starting point for later indigenous development efforts. Theatre ballistic missiles do not optimally disperse chemical and biological weapons, but can deliver nuclear payloads of several kilotons or megatons with accuracy and speed. Currently, roughly 30 countries, including all nuclear weapon possessing states, have theatre ballistic missile capabilities.  The list of supplier states is continuing to grow, and now includes both North Korea and Iran.

  • What Dual-Use Challenges Exist?

    Several countries have developed carrier rockets to lift payloads into space, such as satellites or astronauts. Called space launch vehicles (SLV), these rockets are in their central design principles very similar to an ICBM. A space launch vehicle is a ballistic missile in the sense that it uses several stages of fuel to generate enough engine boost to lift it into space. A country could therefore use a space program to develop knowledge applicable to a ballistic missile program. Countries lacking confirmed ICBM capabilities but with active space programs include Japan, Israel, India, Iran, Brazil, and Pakistan. A similar technological relationship exists between land-attack cruise missiles and both unmanned aerial vehicles (UAVs) and anti-ship cruise missiles. This could provide an opportunity for a country to pursue land-attack cruise missile development under the guise of UAV or anti-ship cruise missile production.  Further, UAVs and anti-ship cruise missiles could potentially be modified outright to produce a land-attack cruise missile.  Such options could offer more feasible and more politically viable options for a country interested in procuring land-attack cruise missile technology.

  • Do Defenses Against Ballistic Missiles Exist?

    Several countries have been developing capabilities to defend against ballistic missiles for decades, though the effectiveness of existing systems remains in question. Such efforts are focused on the deployment of interceptors capable of shooting down a ballistic missile after launch at various stages of its flight path. Today, ballistic missile defense systems are in the development stage that aims to “shoot down a missile with a missile” using sea-based and ground-based systems. However, air- and space-based systems using strong lasers for interception have been researched in the past. The United States and its NATO partners, and to a lesser degree Russia, have frequently taken the lead in the development of missile defense systems, and both have acquired a limited defensive capability against short-range ballistic missiles (in the form of the PAC-3 system for the United States and the more advanced variants of the SA-series for Russia). Other countries including China, Israel, and India have also expressed interest in acquiring defensive systems. The relationship between missile defense and missile proliferation is difficult to characterize.  While some believe that missile defenses diminish the appeal of ballistic missiles, others believe that they encourage larger and more advanced missile arsenals.  For example, countries might pursue technology similar to the Russian SS-27 and RS-24 ICBMs, which Russia claims have the capability to change course during terminal-phase to evade intercept.  They may also, as Pakistan declares it has done with the Babur missile, develop and deploy cruise missiles that can be programmed to evade defense systems.

  • What is a Cruise Missile?

    Unlike ballistic missiles, cruise missiles depend on engine propulsion throughout their entire flight course. In essence, cruise missiles are small, unmanned fixed-wing aircraft equipped with internal guidance systems that carry a payload to a land- or sea- based target. This fundamentally different design allows cruise missiles to fly at almost any trajectory (usually very low to the ground), to hit targets with very high precision, and to adjust to weather conditions. However, cruise missiles are also considerably slower than ballistic missiles, allowing an enemy greater response time, and they carry smaller payloads. Cruise missiles’ slower speeds also better suit biological and chemical payloads. Because it is less expensive to acquire cruise missiles than ballistic missiles, their proliferation is widespread. While Russia and the United States held a near monopoly on land attack cruise missile technology as recently as 20 years ago, global inventories have grown to now include almost 75 models inventoried in just over a dozen countries, with many designed to circumvent export controls by barely undercutting the payload and range cutoffs specified by the Missile Technology Control Regime. Both India and Pakistan now own nuclear-capable cruise missiles.

  • What Role do Combat Aircraft Play as Delivery Systems?

    Manned combat aircraft, namely strike aircraft and bombers, travel slower than ballistic missiles and require expensive maintenance. Also, a functional air force requires the development and maintenance of an extensive support infrastructure, including trained personnel and equipment such as tanker aircraft for aerial refueling. All countries known to possess nuclear weapons and most countries pursuing weapons of mass destruction possess combat aircraft, although the degree to which they rely on this delivery method varies substantially from country to country. Furthermore, delivery of WMD does not require the most technologically sophisticated aircraft (e.g., strike aircraft with all-aspect stealth capabilities). However, the deployment of more advanced aircraft, such as bombers that use stealth technology to reduce their radar signatures, considerably increases the survivability of the aircraft, and makes it more likely that the weapon will be delivered successfully. Not only do many countries already possess combat aircraft, but the trade of such systems in many countries is actively encouraged. A country may be reluctant to sell its most cutting-edge combat aircraft, and the MTCR restricts the trade of some technologies useful for advanced aircraft. However, a country seeking simply to purchase functional combat aircraft capable of delivering a WMD payload likely already possesses this capability, or would have little difficulty finding a willing seller.

  • How is the International Community Working to Address the Delivery Systems Threat?

    No binding international treaty controls the spread of delivery systems for weapons of mass destruction. The 1987 Missile Technology Control Regime (MTCR), an informal voluntary agreement among 34 countries, seeks to coordinate national export controls on missile technologies, and to restrict the transfer of missile materials, equipment, and related technologies. The effectiveness of the MTCR is highly constrained by the fact that the most active proliferators of missile technology (e.g., North Korea), do not adhere to its guidelines. Also, because the MTCR seeks only to prevent the transfer of systems capable of carrying a 500kg payload 300km or more, countries can still gain experience with ballistic missile technology by acquiring systems not covered by these guidelines.

    The 2002 Hague Code of Conduct Against Ballistic Missile Proliferation (HCOC) contains a set of general principles and confidence-building measures that its 132 subscriber states pledge adherence to. Although the HCOC has contributed to the strengthening of a norm against ballistic missile proliferation, it is a non-legally binding agreement, and does not address cruise missile or UAV proliferation. Also, several key countries, including North Korea, Pakistan, and India, do not participate.

  • Sources

    [1] U.S. Congress, Office of Technology Assessment, Technologies Underlying Weapons of Mass Destruction, OTA-BP-ISC-115 (Washington, DC: U.S. Government Printing Office, December 1993).
    [2] U.S. Department of Defense, Weapons of Mass Destruction Technologies (ADA 330102) (Washington, DC: Office of the Under Secretary of Defense for Acquisition and Technology, 1998).
    [3] Duncan Lennox, ed., Jane's Strategic Weapon Systems, Issue Forty-eight, January 2008.
    [4] Dennis Gormley, Missile Contagion: Cruise Missile Proliferation and the Threat to International Security (Annapolis: Naval Institute Press, 2008).

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