National Missile Defense

From Academic Kids

Missing image
A payload launch vehicle carrying a prototype exoatmospheric kill vehicle is launched from Meck Island at the Kwajalein Missile Range on Dec. 3, 2001, for an intercept of a ballistic missile target over the central Pacific Ocean.

National Missile Defense (NMD) is a military strategy that has been discussed in the United States since the 1960s. The basic idea is to shield the U.S. against incoming missiles by shooting them down as they approach the country, and its role in nuclear strategy has been a heated topic for several decades. (See also Missile Defense Agency and Anti-ballistic missile.)


History of NMD

In the late 1950s, the Nike-Zeus program investigated the use of Nike nuclear missiles as interceptors against Soviet ICBMs. A Nike warhead would be detonated at high altitudes (over 100 km /60 miles) above the polar regions in the near vicinity of an incoming Soviet missile. While rocket technology offered some hope of a solution, the problem of how to quickly identify and track incoming missiles proved intractable, especially in light of easily envisioned countermeasures such as decoys and chaff. The Nike-Zeus project was cancelled in 1961.

Project Defender

The Nike-Zeus concept of exploding nuclear warheads over the polar regions (or possibly Canada) was hardly appealing. In the 1960s Project Defender and the Ballistic Missile Boost Intercept concept replaced land-launched Nike missiles with missiles to be launched from satellite platforms orbiting directly above the USSR. Instead of nuclear warheads, the BAMBI missiles would deploy huge wire meshes designed to disable Soviet ICBMs in their early launch phase (the "boost phase"). No solution to the problem of how to protect the proposed satellite platforms against attack was found, however, and the program was cancelled in 1968.

The Sentinel Program

In 1967, U.S. Defense Secretary Robert McNamara announced the Sentinel Program which would have a goal of providing a "thin umbrella" of protection against a limited nuclear strike, such as might be launched by Communist China. McNamara recognized, however, that the deployment of even a limited defensive ABM system might well invite a pre-emptive nuclear attack before it could be implemented. This logic (the theory of Mutually Assured Destruction) drove the U.S. and USSR to sign the ABM Treaty of 1972. Under the ABM treaty and a 1974 revision agreed to by the Soviets and Americans, each country was allowed to deploy a single ABM system with only 100 interceptors to protect a single target. The Soviets deployed a system named Galosh, designed to protect Moscow. The U.S. deployed a system called Safeguard to defend ballistic missile sites at Grand Forks Air Force Base, North Dakota, in 1975.

Homing Overlay Experiment

Given concerns about the previous programs using nuclear tipped interceptors, in the 1980s the U.S. Army began studies about the feasibility of hit-to-kill vehicles, where an interceptor missile would destroy an incoming ballistic missile just by colliding with it head-on.

The first program, which actually tested a hit-to-kill missile interceptor, was the Army's HOE (Homing Overlay Experiment) which used a Kinetic Kill Vehicle (KKV) . The KKV was equipped with an infrared seeker, guidance electronics and a propulsion system. Once in space, the KKV could extend a folded structure similar to an umbrella skeleton of 4 m (13 ft) diameter to enhance its effective cross section. This device would destroy the ICBM reentry vehicle on collision. After test failures with the first three flight tests, the fourth and final test on 10 June 1984 was successful, intercepting the Minuteman RV with a closing speed of about 6.1 km/s at an altitude of more than 160 km.

The Strategic Defense Initiative

Main article: Strategic Defense Initiative

On March 23, 1983 President Reagan announced a new national missile defense program formally called the Strategic Defense Initiative but soon nicknamed "Star Wars" by detractors. President Reagan's stated goal was not just to protect the U.S. and its allies, but to also provide the completed system to the USSR, thus ending the threat of nuclear war for all parties. A partisan debate ensued in Congress, with Democrats questioning the feasibility and strategic wisdom of such a program, while Republicans talked about its strategic necessity and provided a number of technical experts who argued that it was in fact feasible (including respected Manhattan Project physicist Edward Teller). Advocates of SDI prevailed and funding was initiated in fiscal year 1984. The motivation behind this effort largely collapsed with the fall of the Soviet Union and the end of the Cold War.

Recent developments

In the 1990s and early 21st century, the mission of NMD has changed to the more modest goal of preventing the United States from being subject to nuclear blackmail or nuclear terrorism by a so-called rogue state. The feasibility of this more limited goal remains somewhat controversial. Under President Clinton some testing continued but the project was not given much funding. Some have considered this surprising, in light of Clinton's supportive remarks on 5 September 2000. He said that "such a system, if it worked properly, could give us an extra dimension of insurance in a world where proliferation has complicated the task of preserving peace."

On 14 October 2002, a ground based interceptor launched from the Ronald Reagan Ballistic Missile Defense Site destroyed a mock warhead 225km above the Pacific. The test included three decoy balloons. [1] (

On 16 December 2002 President Bush signed National Security Presidential Directive 23 [2] ( which outlined a plan to begin deployment of operational ballistic missile defense systems by 2004. The following day the U.S. formally requested from the UK and Denmark use of facilities in Fylingdales, England, and Thule, Greenland, respectively, as a part of the NMD program. The projected cost of the program for the years 2004 to 2009 will be 53 billion U.S. dollars, making it the largest single line in The Pentagon's budget.

In 2003, NMD was changed to GMD (Ground-Based Missile Defense), to differentiate it from other missile defense programs, such as space-based, sea-based, or high-altitude intercept programs.

On 22 July 2004, the first ground-based interceptor was deployed at Ft. Greely, Alaska. The system will be declared operational with the emplacement of five additional interceptors in September. The system will provide "rudimentary" protection; the Pentagon's chief weapons evaluator estimated its likely effectiveness to be perhaps only 20 percent. [3] (

On 15 December 2004, an interceptor test in the Marshall Islands failed when the launch was aborted due to an "unknown anomaly" in the interceptor, 16 minutes after launch of the target from Kodiak Island, Alaska. [4] (

On 14 February 2005, another interceptor test failed due to a malfunction with the ground support equipment at the test range on Kwajalein Island, not with the interceptor missile itself. [5] (

On 24 February 2005, the Missile Defense Agency, testing the Aegis Ballistic Missile Defense System, successfully intercepted a mock enemy missile. This was the first test of an operationally configured Standard missile 3 interceptor and the fifth successful test intercept using this system. The system is scheduled for operational deployment in 2005. [6] (

July 2003 Report of the American Physical Society

There has been controversy among experts about whether it is technically feasible at all to build a system which intercepts ballistic missiles during their boost phase, as part of the U.S. National Missile Defense program intends.

This technical criticism came especially from U.S. physicists and culminated in the publication of a very critical study on the subject by the American Physical Society.

The study's main point is that it might be possible to develop within several years from now a limited system capable of destroying a liquid-fuel propelled ICBM during the boost phase. It was also found possibly feasible to destroy some solid-propellant launches, such as those from Iran, but not those from North Korea, because of differences in the boost time and citing possibilities for interceptors. However, at this time it is to be expected that the likely users of ICBMs will switch to solid fuel, which makes acceleration faster and the boost phase so short that only few tens of seconds remain to identify, target and destroy the missile. The study concluded that this is unlikely to be achievable with expected advances in technology over the following 15 years.

Using orbital launchers to provide a reliable defense against solid fuel launches from Iran or North Korea was found to require at least 1,600 interceptors in orbit. Reducing the requirement to liquid-fueled missile interception would reduce the number to 700. To allow for the use of two or more interceptors per missile, many more would be required.

If operating in the region, within 300 km of intercept point for a solid fuel missile, 600 km for liquid, the use of the airborne laser was found to possibly be credible, though solid fuel launchers are more resistant than liquid-fueled systems. There is considerable uncertainty about the actual capability of the system.

In summary, the report concluded that:

Given the results that follow from our assumptions, we conclude that while the boost phase technologies we studied are potentially capable of defending the United States against liquid-propellant ICBMs at certain ranges of interest, at least in the absence of counter-measures, when all factors are considered none of the boost-phase defense concepts studied would be viable for the foreseeable future to defend the nation against even first-generation solid-propellant ICBMs.

See also the article on anti-ballistic missiles for further discussion on the feasibility of NMD-like systems.

See also


External links


Academic Kids Menu

  • Art and Cultures
    • Art (
    • Architecture (
    • Cultures (
    • Music (
    • Musical Instruments (
  • Biographies (
  • Clipart (
  • Geography (
    • Countries of the World (
    • Maps (
    • Flags (
    • Continents (
  • History (
    • Ancient Civilizations (
    • Industrial Revolution (
    • Middle Ages (
    • Prehistory (
    • Renaissance (
    • Timelines (
    • United States (
    • Wars (
    • World History (
  • Human Body (
  • Mathematics (
  • Reference (
  • Science (
    • Animals (
    • Aviation (
    • Dinosaurs (
    • Earth (
    • Inventions (
    • Physical Science (
    • Plants (
    • Scientists (
  • Social Studies (
    • Anthropology (
    • Economics (
    • Government (
    • Religion (
    • Holidays (
  • Space and Astronomy
    • Solar System (
    • Planets (
  • Sports (
  • Timelines (
  • Weather (
  • US States (


  • Home Page (
  • Contact Us (

  • Clip Art (
Personal tools