Strategic Defense Initiative (SDI), often referred to as “Star Wars,” a research-and-development program announced by U.S. President Ronald Reagan in March 1983 to explore largely space-based means of detecting, intercepting, and destroying strategic nuclear missiles launched by the Soviet Union. Pentagon reports in the early 1980s claimed the Soviet Union had improved the accuracy for its missiles and, if true, that threatened to undermine the existing U.S. strategy of Mutual Assured Destruction (MAD) by rendering U.S. land-based strategic missiles more vulnerable. In response to this perceived vulnerability and inspired by calls from retired U.S. Army Lieutenant General Daniel O. Graham and his High Frontier organization for a national missile defense system, President Reagan chose to initiate a long-term, technically daunting, extremely expensive program to create a complex, space-based missile defense system. In National Security Decision Directive 85, he affirmed the U.S. commitment to eliminate the threat from Soviet missiles. The president envisioned a system neither susceptible to offensive countermeasures nor easily overwhelmed by a mass raid of Soviet missiles.
In January 1984 National Security Decision Directive 119 formally established SDI and three months later the Strategic Defense Initiative Organization (SDIO) was created within the U.S. Department of Defense (DoD) with U.S. Air Force Lieutenant General James A. Abrahamson Jr. as its director. For its agenda and schedule, the SDIO initially turned to an October 1983 report from an Office of Technology Assessment panel headed by James Fletcher, former administrator of NASA. It began exploring technologies in five general areas: directed-energy weapons, such as lasers and particle beams; kinetic-energy weapons that physically hit a target; systems concepts and battle management; survivability and lethality; and systems for surveillance, target acquisition, tracking, and kill assessment. Researchers soon acknowledged that significant technological advances would be necessary before engineers could design small, lightweight, relatively inexpensive, reliable space-based missile “killers.”
During an October 1986 conference between Soviet President Mikhail Gorbachev and President Reagan in Reykjavik, Iceland, Reagan rejected the idea of limiting SDI strictly to research in exchange for reductions in the Soviet nuclear arsenal. By summer 1987 the SDIO recommended to the DoD Acquisition Board a plan to transition from research and development to phased deployment of a Strategic Defense System (SDS). Meanwhile U.S. reinterpretation of the 1972 ABM Treaty claimed it did not prohibit development and testing of space-based missile defenses, including a system like the nuclear-powered X-ray laser. Recognizing, however, that live-fire testing of any strategic missile defense system posed nearly insurmountable challenges, the SDIO broke ground in March 1988 for a National Test Facility (NTF) at Falcon (later Schriever) Air Force Base (AFB) near Colorado Springs, Colorado. The NTF became the hub of the SDI National Test Bed, a distributed network of computers at numerous government, corporate, and academic sites across the United States that performed complicated modeling, simulation, and actual hardware-in-the-loop testing of various missile defense systems.
The first phase of SDS deployment included six systems: the Boost Surveillance and Tracking System, the Ground-based Surveillance and Tracking System, the Space-based Surveillance and Tracking System, the Exoatmospehric Reentry Vehicle Interceptor Subsystem, the Space-based Interceptor System, and the Battle Management Command, Control, and Communications System. Before implementation of the first phase occurred, however, the Cold War between the United States and Soviet Union ended, significantly diminishing the threat of attack by intercontinental ballistic missiles. Furthermore the high cost and technical difficulties associated with SDI had caused politically powerful Senator Sam Nunn of Georgia to propose that development be refocused toward a more limited system for protection against accidental or unauthorized launches.
By January 1991 President George H. W. Bush had restructured SDI, calling it Global Protection Against Limited Strikes (GPALS). Three components characterized GPALS: theater missile defense (TMD) capabilities, a national missile defense (NMD) system, and a space-based, boost-phase interceptor system known as Brilliant Pebbles. President William Clinton's administration canceled Brilliant Pebbles in 1993 and drastically cut TMD and NMD funding. In May 1993 Secretary of Defense Les Aspin renamed the SDIO the Ballistic Missile Defense Organization (BMDO) and reoriented its priorities toward TMD development. Those actions essentially terminated SDI as Reagan originally envisioned it, but the concepts and technological progress continued into the twenty-first century.
Deployment of an NMD system became the goal of some congressional Republicans during the late 1990s. The Commission to Assess the Ballistic Missile Threat to the United States, established under the 1998 Defense Authorization Act and chaired by Donald Rumsfeld, warned in July 1998 that the ballistic missile threat against the United States remained real and credible. In May 2001 President George W. Bush told a National Defense University audience that an NMD system would allow the United States to move away from massive retaliation and MAD as a strategy. Secretary of Defense Rumsfeld redesignated BMDO as the Missile Defense Agency in January 2002 and charged it with deploying elements of the NMD system as soon as practicable, while continuing to develop and test additional technologies. During 2004, DoD began placing in underground silos at Fort Greely, Alaska, and Vandenberg AFB, California, the first interceptors for the Ground-based Midcourse Defense segment of the NMD system.
See also: Antiballistic Missile (ABM) Treaty
U.S. Department of Defense. http://www.defense.gov/.
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