U.S. Missile Defense Programs at a Glance

Ballistic Missile Basics

Ballistic missiles are powered by rockets initially but then they follow an unpowered, free-falling trajectory toward the target. They are classified by the maximum distance that they can travel, which is a function of how powerful the missile’s engines (rockets) are and the weight of the missile’s warhead. To add more distance to a missile’s range, rockets are stacked on top of each other in a configuration referred to as staging. There are four general classifications of ballistic missiles:

• Short-range ballistic missiles, traveling less than 1,000 kilometers (approximately 620 miles)
• Medium-range ballistic missiles, traveling between 1,000–3,000 kilometers (approximately 620-1,860 miles)
• Intermediate-range ballistic missiles, traveling between 3,000–5,500 kilometers (approximately 1,860-3,410 miles)
• Intercontinental ballistic missiles (ICBMs), traveling more than 5,500 kilometers

Short- and medium-range ballistic missiles are referred to as theater ballistic missiles, whereas ICBMs or long-range ballistic missiles are described as strategic ballistic missiles. The ABM Treaty prohibited the development of nationwide strategic defenses, but permitted development of theater missile defenses.

Ballistic missiles have three stages of flight:

• The boost phase begins at launch and lasts until the rocket engines stop firing and pushing the missile away from Earth. Depending on the missile, this stage lasts between three and five minutes. During much of this time, the missile is traveling relatively slowly, although toward the end of this stage an ICBM can reach speeds of more than 24,000 kilometers per hour. The missile stays in one piece during this stage.
• The midcourse phase begins after the rockets finish firing and the missile is on a ballistic course toward its target. This is the longest stage of a missile’s flight, lasting up to 20 minutes for ICBMs. During the early part of the midcourse stage, the missile is still ascending toward its apogee, while during the latter part it is descending toward Earth. It is during this stage that the missile’s warhead, as well as any decoys, separate from the delivery vehicle.
• The terminal phase begins when the missile’s warhead re-enters the Earth’s atmosphere, and it continues until impact or detonation. This stage takes less than a minute for a strategic warhead, which can be traveling at speeds greater than 3,200 kilometers per hour.

Short- and medium-range ballistic missiles may not leave the atmosphere, have separating warheads, or be accompanied by decoys or other countermeasures.

Program & Key Elements

• The key element of the ground-based midcourse defense is a ground-based missile interceptor consisting of a powerful multistage booster and an exoatmospheric kill vehicle (EKV), which separates from the booster in space and seeks out its target through radar updates and use of its onboard visual and infrared sensors.
• The EKV destroys its target by colliding with it. This process is referred to as hit-to-kill.

• The projected system’s goal is to intercept strategic ballistic missile warheads in the midcourse stage.

• To date, the system has had five successful intercept attempts in eight developmental tests.
• After four straight successes, the system failed to hit its target in its last test December 11, 2002. Another intercept attempt will not take place until after the administration is expected to declare an initial system operational in September or October.
• The interceptor’s multistage booster and EKV have yet to be tested together. They were first supposed to be paired together in an intercept attempt in early 2001.

• All the intercept tests to date have involved substitute components in highly scripted scenarios. A C-band transponder on the target provides tracking data used to formulate the system’s initial intercept plan; the target and interceptor fly the same trajectories in every test; the intercepts take place at slower speeds and lower altitudes than what would be expected in a real attack; the interceptor is preprogrammed with information on what the target looks like before the intercept attempt; and the tests do not involve realistic decoys that a potential adversary might use to trick the system into hitting the wrong object.
• The Pentagon is currently planning to deploy six missile interceptors, at Fort Greely, Alaska, and four more interceptors at Vandenberg Air Force Base, California, by early 2005. Another 10 interceptors are to be deployed at Fort Greely before the end of 2005.
• There are no plans to fire interceptors from Fort Greely for testing purposes.
• The Pentagon’s top independent weapons tester, Thomas Christie, wrote in a May 17, 2004 letter to Sen. Wayne Allard (R-Colo.) that “Conducting realistic operational testing in the near term for the GMD element would be premature and not beneficial to the program.” In other words, the system has not yet reached a state in its development that would permit it to be tested in real-world type scenarios. The Pentagon’s Missile Defense Agency (MDA) says the system must be deployed first before it can be subjected to such tests.
• Although some top Pentagon officials have expressed confidence that the initial system will be capable of countering ballistic missiles launched by North Korea, Christie testified in March 2004 that it was uncertain whether it would be able to do so.
• The interceptors under the Clinton plan were to have been supported by a land-based X-band radar, but the Bush administration announced plans August 31, 2002, to develop a sea-based X-band radar instead. This new version will not be available until at least the end of 2005.
• Bush’s plans also call for the missile interceptors to be supported by an upgraded, although less capable, early-warning radar on Shemya Island at the western tip of the Aleutian Islands chain. This radar, known as the Cobra Dane radar, will only be able to track missiles fired from the direction of Asia because the radar is fixed to face northwest.
• MDA is also exploring the construction of a third missile defense site in Europe. Former MDA Director Lieutenant General Ronald Kadish testified in March 2004 that such work could begin as early as 2006.
• The United States is upgrading two foreign-based, early-warning radars to help track ballistic missiles launched from the direction of the Middle East. One radar (Fylingdales) is located in the United Kingdom and the other is at Thule Air Base in Greenland. Fylingdales is supposed to be operational by the end of 2005, while the Thule-based radar will not be up and running until at least 2006.

Program & Key Elements

• The key elements of the proposed sea-based defense are a ship-based missile (Standard Missile- 3, or SM-3) and the Aegis combat system, an advanced system that can detect and track more than 100 targets simultaneously while directing a ship’s weapons to counter incoming air, sur face, and submarine threats.
• The SM-3 is a hit-to-kill missile comprised of a three-stage booster with a kill vehicle.
• The SM-3 is considered too slow to intercept a strategic ballistic missile.

• Initially, the Aegis BMD is geared toward defending against short-, medium-, and intermediate-range ballistic missiles during their midcourse phase with an emphasis on the ascent stage.
• Eventually, the Pentagon wants the defense to be capable of countering strategic ballistic missiles, possibly in the boost phase.
• A senior Pentagon official announced May 2, 2002, that the Pentagon would also explore whether the system can be adapted to counter short-and medium-range ballistic missiles in their terminal stage.

• The system has a record of four intercepts in five flight tests. The last test succeeded on Dec. 11, 2003, but the Pentagon subsequently suspended further flight testing for at least a year until a problem with the interceptor’s kill vehicle can be fixed. The kill vehicle cannot maneuver as it is supposed to.
• The target used in the five intercept tests is not reflective of what the system is expected to engage in a real-world situation. The target used is larger and slower-moving than what the defense is expected to counter.
• The General Accounting Office (GAO), which conducts investigations for Congress, has described testing of the system as “highly scripted.”

• As part of its initial missile defense capability, the Bush administration announced Dec. 17, 2002, that it would try to deploy up to 20 sea-based interceptors on three ships during 2004 and 2005. Another 15 ships are to receive upgraded radars to improve their missile tracking capabilities. But Pentagon plans have been scaled back due to problems with the interceptor’s kill vehicle and delays with the radar upgrades. Current plans envision having three ships armed with up to 10 total missiles by the end of 2005 and 10 ships outfitted with upgraded radars.
• The Pentagon intends to deploy two of the ships with upgraded radars in late 2004 for patrolling missions in the Sea of Japan.

Program & Key Elements

• The key element of the proposed ABL system is a modified Boeing 747 plane equipped with a chemical oxygen-iodine laser.
• The laser beam is produced by a chemical reaction.

• Although the Pentagon originally aimed to field the ABL against theater ballistic missiles, the Pentagon now contends the ABL may have an inherent capability against strategic ballistic missiles as well.
• The expanded ABL objective is to shoot down all ranges of ballistic missiles in their boost phase.

• The first ABL test plane made its inaugural flight on July 18, 2002. The plane was not equipped with the laser, which is still under development.
• Although Clinton administration plans first projected an ABL intercept attempt to take place in 2003, development delays have led the Pentagon to push back such a test several times. It is now uncertain when the test could occur, but it will not happen before 2005.
• Kadish candidly acknowledged the ABL woes in March 2004 testimony, declaring that the project has “been costing us more money and taking longer to do.”

• The Pentagon said in 2002 that it wanted to have one ABL available for emergency use in 2004 and two or three ABL aircraft operational between 2006 and 2008. At this time, the earliest an ABL aircraft will be available for any use is 2006. The Pentagon is aiming to officially deploy the system between 2008 and 2010.

Program & Key Elements

• THAAD’s main components are a missile comprised of a single rocket booster with a separating kill-vehicle that seeks out its target with the help of a specifically designed THAAD radar.
• The THAAD kill vehicle is hit-to-kill.
• THAAD missiles are fired from a truck-mounted launcher.

• THAAD’s mission is to intercept short- and medium-range ballistic missiles at the end of their midcourse stage and in the terminal stage. Intercepts could take place inside or outside the atmosphere.

• The system had two successful intercept attempts in the summer of 1999 after experiencing six test failures between April 1995 and March 1999.
• The THAAD missile is currently being redesigned.

• THAAD flight tests are scheduled to resume in late 2004 or early 2005. Intercept testing is slated to begin in late 2005, although testing against threat representative targets is not expected to occur until the following year.
• Current Pentagon plans call for THAAD testing through at least 2008, although the Pentagon also envisions deploying THAAD interceptors sometime between 2006 and 2008.

Program & Key Elements

• PAC-3 consists of a one-piece, hit-to-kill missile interceptor fired from a mobile launching station, which can carry 16 PAC-3 missiles.
• The missile is guided by an independent radar that sends its tracking data to the missile through a mobile engagement control station.

• PAC-3 is designed to defend against short- and medium-range ballistic missiles in their terminal stage at lower altitudes than the THAAD system.

• During earlier developmental testing, the system struck nine out of 10 targets.
• In four, more difficult operational tests between February and May 2002 that involved multiple interceptors and targets, seven PAC-3s were to be fired at five targets. Of the seven PAC-3s, two destroyed their targets, one hit but did not destroy its target, one missed its target, and three others did not launch.
• PAC-3s destroyed two Iraqi short-range ballistic missiles in the latest conflict and shot down a U.S. fighter jet. Earlier Patriot models also deployed to the region shot down seven Iraqi missiles and a British combat aircraft.

• PAC-3 is now considered operational.
• As of July 2004, 175 PAC-3 interceptors had been delivered to the Army.

Program & Key Elements

• STSS will initially comprise two satellites, but the constellation could expand to as many as 30 satellites.

• STSS satellites are expected to support U.S. missile defense systems by providing tracking data on missiles during their entire flight.

• The two STSS satellites are to be launched in fiscal year 2007. The SBIRS-low program had called for the first launch of a satellite a year earlier.

• The first next-generation STSS satellite is to be launched in 2011.
• Two satellites would provide little, if any, operational capability. The Pentagon estimates that at least 18 satellites would need to be deployed to provide coverage of key regions of concern. Worldwide coverage could require up to 30 satellites.

Program & Key Elements

• SBIRS-high will be comprised of four satellites in geosynchronous orbit and sensors on two host satellites in a highly elliptical orbit.

• SBIRS-high’s primary objective is to provide early warning of global ballistic missile launches.

• Although the Air Force intended to begin launching components of the system in 2003, all plans are being revised due to significant schedule delays and cost overruns.

• Uncertain. The Air Force and private contractors are working out a new schedule, which is supposed to be ready by September 2004.

Program & Key Elements

• KEI will be comprised of three powerful boosters and a separating kill vehicle. The booster is expected to travel at least six kilometers per second, which is comparable to an ICBM.
• The kill vehicle will not carry an explosive warhead but is designed to destroy its target through the force of a collision.
• The Pentagon is developing mobile land- and sea-based versions of KEI and holding out the possibility of a possible space-based version.

• KEI is intended to destroy strategic ballistic missiles during their first minutes of flight when their rocket engines are still burning.

• On Dec. 3, 2003, the Pentagon awarded Northrop Grumman a contract worth up to $4.5 billion to develop KEI over eight years.

• Current program goals are to build a prototype interceptor between 2006 and 2008 and initiate flight testing in 2008.
• The Pentagon is seeking deploy the mobile land-based version of KEI first. It hopes to accomplish this by as early as 2010.
• The Pentagon awarded the KEI contract several months after the independent American Physical Society released a study asserting that boost-phase intercepts would be technically possible under very limited circumstances.