Missiles

Ballistic Missiles. A ballistic missile is a rocket capable of guiding and propelling itself in a direction and to a velocity that, when the rocket engine shuts down, it will follow a flight pattern to a desired target. Ballistic missiles burn most of their propellant (fuel) in the initial portion of their flight, called the boost phase. Most fly fast enough to hit targets hundreds or thousands of miles away in a few minutes. Once launched, they are fairly easy to detect with radar or other sensors, but extremely difficult (some would argue practically impossible) to intercept. This is particularly true for missiles with longer range, such as intercontinental ballistic missiles (ICBMs).

Approximately, 32 countries possess ballistic missiles. Nations that have WMD usually seek to buy or develop ballistic missiles to deliver such weapons to enemy targets; the eight countries with nuclear weapons (the United States, United Kingdom, Russia, China, France, India, Pakistan, and Israel) all have operational ballistic missiles. Only these eight countries, Iran, and North Korea have produced or tested missiles with ranges over 1,000 kilometers. These countries want such missiles because, at least to date, they could be certain of penetrating enemy defenses. For this reason, slowing the spread of ballistic missiles and developing defenses against them have become important elements of efforts to prevent the use of WMD.

Cruise Missiles. Technically, a cruise missile is an unmanned, self-propelled guided vehicle that sustains flight through aerodynamic lift (like an airplane) for most of its flight path. Like a ballistic missile, its primary mission is to place ordnance or a special payload on a target. One important difference between ballistic missiles and cruise missiles is that cruise missiles remain in the atmosphere for the entire duration of flight. Also, since cruise missiles rely on the thrust of their engines and aerodynamic lift, similar to an airplane, they may be controlled or even redirected during flight. Ballistic missiles, on the other hand, follow a path that is determined almost entirely during their initial boost phase and cannot be redirected during flight.  Many cruise missiles are capable of flying close to the ground and using other means to avoid detection by radar.

There are two main varieties of cruise missiles. The first are sea-launched cruise missiles (SLCMs), which are launched from submarines or surface ships. The second are air-launched cruise missiles (ALCMs), which are launched from aircraft, such as heavy bombers.

Most cruise missiles carry conventional warheads.  In August 2005, the United States tested a long-range cruise missile with a boosted penetrator warhead that can be used against hard and deeply buried targets. The United States, Russia, and China, however, deploy cruise missiles with nuclear warheads as well.

Further Reading:

	CRS, Paul Kerr, "Nuclear, Biological, and Chemical Weapons and Missiles: Status and Trends"
	Arms Control Association, Missile Proliferation
	CRS, Andrew Feickert, "Missile Survey: Ballistic and Cruise Missiles of Foreign Countries"
	CNS, Mountbatten Centre, International Perspectives on Missile Proliferation and Defenses
	UNIDIR, "The Issue of Missiles in All Its Aspects"
	Arms Control Today,  Aaron Karp, "Going Ballistic? Reversing Missile Proliferation"
	CNS, Missile Proliferation and Defences: Problems and Prospects
	NTI, Dennis Gormley, "The Risks and Challenges of a Cruise Missile Tipping Point"
	CRS, Andrew Feickert, "Cruise Missile Proliferation"