Strategic Defense Initiative
Overview
The Strategic Defense Initiative (SDI) was proposed by U.S. President Ronald Reagan
Ronald Reagan
Ronald Wilson Reagan was the 40th President of the United States , the 33rd Governor of California and, prior to that, a radio, film and television actor....

 on March 23, 1983 to use ground and space-based systems to protect the United States from attack by strategic nuclear
Nuclear weapon
A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission or a combination of fission and fusion. Both reactions release vast quantities of energy from relatively small amounts of matter. The first fission bomb test released the same amount...

 ballistic missile
Ballistic missile
A ballistic missile is a missile that follows a sub-orbital ballistic flightpath with the objective of delivering one or more warheads to a predetermined target. The missile is only guided during the relatively brief initial powered phase of flight and its course is subsequently governed by the...

s. The initiative focused on strategic defense rather than the prior strategic offense doctrine of mutual assured destruction
Mutual assured destruction
Mutual Assured Destruction, or mutually assured destruction , is a doctrine of military strategy and national security policy in which a full-scale use of high-yield weapons of mass destruction by two opposing sides would effectively result in the complete, utter and irrevocable annihilation of...

 (MAD). The Strategic Defense Initiative Organization (SDIO) was set up in 1984 within the United States Department of Defense
United States Department of Defense
The United States Department of Defense is the U.S...

 to oversee the Strategic Defense Initiative.

The ambitious initiative was "widely criticized as being unrealistic, even unscientific" as well as for threatening to destabilize MAD and re-ignite "an offensive arms race".
Encyclopedia
The Strategic Defense Initiative (SDI) was proposed by U.S. President Ronald Reagan
Ronald Reagan
Ronald Wilson Reagan was the 40th President of the United States , the 33rd Governor of California and, prior to that, a radio, film and television actor....

 on March 23, 1983 to use ground and space-based systems to protect the United States from attack by strategic nuclear
Nuclear weapon
A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission or a combination of fission and fusion. Both reactions release vast quantities of energy from relatively small amounts of matter. The first fission bomb test released the same amount...

 ballistic missile
Ballistic missile
A ballistic missile is a missile that follows a sub-orbital ballistic flightpath with the objective of delivering one or more warheads to a predetermined target. The missile is only guided during the relatively brief initial powered phase of flight and its course is subsequently governed by the...

s. The initiative focused on strategic defense rather than the prior strategic offense doctrine of mutual assured destruction
Mutual assured destruction
Mutual Assured Destruction, or mutually assured destruction , is a doctrine of military strategy and national security policy in which a full-scale use of high-yield weapons of mass destruction by two opposing sides would effectively result in the complete, utter and irrevocable annihilation of...

 (MAD). The Strategic Defense Initiative Organization (SDIO) was set up in 1984 within the United States Department of Defense
United States Department of Defense
The United States Department of Defense is the U.S...

 to oversee the Strategic Defense Initiative.

The ambitious initiative was "widely criticized as being unrealistic, even unscientific" as well as for threatening to destabilize MAD and re-ignite "an offensive arms race". It was soon derided as Star Wars, after the popular 1977 film
Star Wars Episode IV: A New Hope
Star Wars Episode IV: A New Hope, originally released as Star Wars, is a 1977 American epic space opera film, written and directed by George Lucas. It is the first of six films released in the Star Wars saga: two subsequent films complete the original trilogy, while a prequel trilogy completes the...

 by George Lucas
George Lucas
George Walton Lucas, Jr. is an American film producer, screenwriter, and director, and entrepreneur. He is the founder, chairman and chief executive of Lucasfilm. He is best known as the creator of the space opera franchise Star Wars and the archaeologist-adventurer character Indiana Jones...

. In 1987, the American Physical Society
American Physical Society
The American Physical Society is the world's second largest organization of physicists, behind the Deutsche Physikalische Gesellschaft. The Society publishes more than a dozen scientific journals, including the world renowned Physical Review and Physical Review Letters, and organizes more than 20...

 concluded that a global shield such as "Star Wars" was not only impossible with existing technology, but that ten more years of research was needed to learn whether it might ever be feasible.

Under the administration of President Bill Clinton
Presidency of Bill Clinton
The United States Presidency of Bill Clinton, also known as the Clinton Administration, was the executive branch of the federal government of the United States from January 20, 1993 to January 20, 2001. Clinton was the first Democratic president since Franklin D. Roosevelt to win a second full term...

 in 1993, its name was changed to the Ballistic Missile Defense Organization
Ballistic Missile Defense Organization
The Ballistic Missile Defense Organization was an agency of the United States Department of Defense that began on 20 May 1974 with the responsibility for all U.S. ballistic missile defense efforts. It evolved from the SAFEGUARD System Organization. The original mission of BMDO was comparable to...

 (BMDO) and its emphasis was shifted from national missile defense to theater missile defense; and its scope from global to more regional coverage. It was never truly developed or deployed, though certain aspects of SDI research and technologies paved the way for some anti-ballistic missile
Anti-ballistic missile
An anti-ballistic missile is a missile designed to counter ballistic missiles .A ballistic missile is used to deliver nuclear, chemical, biological or conventional warheads in a ballistic flight trajectory. The term "anti-ballistic missile" describes any antimissile system designed to counter...

 systems of today. BMDO was renamed to the Missile Defense Agency
Missile Defense Agency
The Missile Defense Agency is the section of the United States government's Department of Defense responsible for developing a layered defense against ballistic missiles. The agency has its origins in the Strategic Defense Initiative, which was established in 1983 and was headed by Lt...

 in 2002. This article covers defense efforts under the SDIO.

Under the SDIO's Innovative Sciences and Technology Office, headed by physicist and engineer James A. Ionson, the investment was predominantly made in basic research
Basic Research
Basic Research is an herbal supplement and cosmetics manufacturer based in Salt Lake City, Utah that distributes products through a large number of subsidiaries. In addition, their products are sold domestically and internationally through a number of high-end retailers. Dennis Gay is the...

 at national laboratories, universities, and in industry, and these programs have continued to be key sources of funding for top research scientists in the fields of high-energy physics, supercomputing/computation
Computation
Computation is defined as any type of calculation. Also defined as use of computer technology in Information processing.Computation is a process following a well-defined model understood and expressed in an algorithm, protocol, network topology, etc...

, advanced materials, and many other critical science and engineering disciplines: funding which indirectly supports other research work by top scientists, and which would be largely unavailable outside of the defense budget environment.

Bombers to ICBMs

Although the Germans put considerable effort into the first surface-to-air missile
Surface-to-air missile
A surface-to-air missile or ground-to-air missile is a missile designed to be launched from the ground to destroy aircraft or other missiles...

s (SAMs) after 1943, they did not have enough time to develop operational-level weapons before the war ended.

Their research proved valuable to teams in the US and USSR, where missile programs slowly developed in the immediate post-war era. As the cold war
Cold War
The Cold War was the continuing state from roughly 1946 to 1991 of political conflict, military tension, proxy wars, and economic competition between the Communist World—primarily the Soviet Union and its satellite states and allies—and the powers of the Western world, primarily the United States...

 started, the Soviets found themselves facing massive USAF and RAF bomber fleets they could not hope to counter in the air. In response they dramatically increased their efforts in SAM development, deploying the SA-1 Guild
SA-1 Guild
The S-25 Berkut is a surface-to-air guided missile, the first operational SAM system in the world. Its NATO reporting name is SA-1 Guild. It was used only to defend Moscow, while the more mobile S-75 would be used in almost all other roles...

 system around Moscow as early as 1955. This was followed by the dramatically improved and semi-mobile SA-2 Guideline, a weapon that remains in service in the 2000s. Similar US and UK weapons soon followed. By the late 1950s, as missiles developed both in quality and number, the ability for the US air fleet to penetrate Soviet airspace was increasingly at risk.

In response, both sides increased their efforts to develop long-range missiles. The Soviets, with no effective bomber force of their own, put considerable effort into their program and quickly brought their basic R-7 Semyorka
R-7 Semyorka
The R-7 was a Soviet missile developed during the Cold War, and the world's first intercontinental ballistic missile. The R-7 made 28 launches between 1957 and 1961, but was never deployed operationally. A derivative, the R-7A, was deployed from 1960 to 1968...

 system into operation in 1959. The US's SM-65 Atlas followed almost immediately thereafter. These early examples were useful only for attacking large targets like cities or ports, but their relative invulnerability and low cost provided both sides with a credible force in an era of stiffening air defenses.

ABMs

At first it appeared that the ICBM could be countered by systems similar to the ever-evolving SAMs already in operation. The ICBM's high trajectory meant they became visible to defensive radars not long after being launched, which meant that defensive systems would have time to prepare. Although they moved quickly in flight, early re-entry systems slowed dramatically once they reached the lower atmosphere, which gave time for a fast missile to attack it. By the early 1960s both nations were working on their first anti-ballistic missile
Anti-ballistic missile
An anti-ballistic missile is a missile designed to counter ballistic missiles .A ballistic missile is used to deliver nuclear, chemical, biological or conventional warheads in a ballistic flight trajectory. The term "anti-ballistic missile" describes any antimissile system designed to counter...

 (ABM) systems.

As ABMs were being developed, countermeasures were also being studied. As the systems generally used long-range radars to find and track the incoming warheads, the simplest solution was to add radar reflectors and other decoys to the launch. These took up little room or weight, but would make a radar return that looked like an additional warhead. This would force the defender to use more ABMs to ensure the "right" object was hit, or wait until they started to re-enter, when the lighter objects would slow down faster and leave the warhead racing ahead. Neither option was particularly attractive in cost terms, generally requiring more and faster missiles.

A better understanding of EMP
EMP
EMP or Emp may refer to:Science and technology*Electromagnetic propulsion*Electromagnetic pulse, a burst of electromagnetic radiation*Electron microprobe microanalyzer, a tool for chemical composition determination...

 presented new problems; a warhead set off at high altitudes and long ranges from the defensive missiles could blind the radars, making the incoming warheads only become visible at lower altitudes. This would further reduce the amount of time the ABM system had to react. Systems using non-obvious approaches might be able to blind the radars in a sneak attack; the Soviets developed the R-36 with a system called Fractional Orbital Bombardment System
Fractional Orbital Bombardment System
The Fractional Orbital Bombardment System was a Soviet ICBM program in the 1960s that after launch would go into a low Earth orbit and would then de-orbit for an attack. It had no range limit and the orbital flight path would not reveal the target location...

 to allow attacks on US missile fields from low altitudes and/or from the south, while the US relied on manned bombers for the same role.

Making matters worse was the continual increase in ICBM numbers. Even before the systems were ready for use, the number of interceptor missiles needed to effectively deter an attack kept increasing. As the ABM systems were expensive, it appeared the simplest way to defeat them was to simply make more ICBMs and deliberately start an arms race the defender could not win. The introduction of MIRV systems dramatically upset this in the favour of the attack; missiles now carried several warheads that would be dispersed over wide areas, so now every new ICBM built would require a small fleet of ABMs to counter it. Both the US and USSR rushed to introduce new weapons with MIRV systems, and the number of warheads in the world rapidly proliferated.

Whether or not deploying an ABM system was worthwhile was a highly contentious issue. The US scaled back their plans significantly and their Sentinel Program aimed only to counter the small Chinese ICBM force, a limited Soviet attack or an accidental launch. By the late 1960s, widespread efforts were underway to solve the problem diplomatically instead of with more missiles. The Anti-Ballistic Missile Treaty
Anti-Ballistic Missile Treaty
The Anti-Ballistic Missile Treaty was a treaty between the United States and the Soviet Union on the limitation of the anti-ballistic missile systems used in defending areas against missile-delivered nuclear weapons....

, signed in 1972, placed limits on the number of ABM systems, later followed by limits on the number of warheads. Both countries continued to deploy a single ABM site; the US briefly deployed a single site under their Safeguard Program
Safeguard Program
The Safeguard Program was a United States Army anti-ballistic missile system developed during the late 1960s. Safeguard was designed to protect U.S. ICBM missile sites from counterforce attack, thus preserving the option of an unimpeded retaliatory strike. Safeguard used much of the same technology...

, while the Soviets deployed A35/A135 missile defense system
A-35 anti-ballistic missile system
The A-35 anti-ballistic missile system, or A-35 Aldan, was a Soviet military battle management radar complex deployed around Moscow to intercept enemy missiles targeting the city or its surrounding areas. In development since the 1960s and in operation from 1971 until the 1990s, It featured the...

 around Moscow.

Attack from above

Throughout the development of the ABM, another possibility existed that avoided most of these problems. If the interceptors were placed in orbit, some of them could be positioned over the Soviet Union at all times. These would fly "down hill" to attack the missiles, so they could be considerably smaller and cheaper than an interceptor that needed to launch up from the ground. It was also much easier to track the ICBMs during launch, due to their huge infrared
Infrared
Infrared light is electromagnetic radiation with a wavelength longer than that of visible light, measured from the nominal edge of visible red light at 0.74 micrometres , and extending conventionally to 300 µm...

 signatures, and disguising these signatures would require the construction of large rockets instead of small radar decoys. Moreover, each interceptor could kill one ICBM; MIRV had no effect. As long as the interceptor missile was inexpensive, the advantage was on the side of the defense.

The US Air Force had studied these concepts under "Project Defender" as early as 1958, which included work on the "Ballistic Missile Boost Interceptor", or BAMBI. BAMBI interceptors would be deployed on a series of satellites, and would be launched towards ICBMs as they climbed. As they approached the ICBM, they would open a large metal net, which would destroy the missile on impact. Depending on assumptions about the accuracy of the system and the number of missiles it would have to face, between 400 and 3,600 such satellites would be needed in order to keep enough above the USSR at any one time. The Air Force concluded that there was simply no way to launch the required number of satellites, let alone have any way to service them. As their space logistical abilities improved through the 1960s they continued to study the problem, but in each case the problem of increasing ICBM numbers meant the numbers of interceptors needed grew to overwhelm any possible launch capability.

However, the introduction of the laser
Laser
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of photons. The term "laser" originated as an acronym for Light Amplification by Stimulated Emission of Radiation...

 in the 1960s appeared to offer the possibility of a way out of the problem. The amount of time needed to attack any one missile was known as the "dwell time", and if a powerful laser had a short dwell time, say 10 seconds, it would be able to attack multiple missiles during the minutes while the ICBM was launching. Given current laser energies this was impractical, but the concept was studied throughout the 1960s and later.

X-ray laser

In 1979 Edward Teller
Edward Teller
Edward Teller was a Hungarian-American theoretical physicist, known colloquially as "the father of the hydrogen bomb," even though he did not care for the title. Teller made numerous contributions to nuclear and molecular physics, spectroscopy , and surface physics...

 contributed to a Hoover Institution
Hoover Institution
The Hoover Institution on War, Revolution and Peace is a public policy think tank and library founded in 1919 by then future U.S. president, Herbert Hoover, an early alumnus of Stanford....

 publication where he claimed that the US would be facing an emboldened USSR due to their work on civil defense
Civil defense
Civil defense, civil defence or civil protection is an effort to protect the citizens of a state from military attack. It uses the principles of emergency operations: prevention, mitigation, preparation, response, or emergency evacuation, and recovery...

. Two years later at a conference in Italy, he made the same claims about their ambitions, but with a subtle change; now he claimed that the reason for their boldness was their development of new space-based weapons. In fact, there was no evidence at all that such research was being carried out, what had really changed was that Teller was now selling his latest nuclear weapon, the x-ray laser
X-ray laser
An X-ray laser is a device that uses stimulated emission to generate or amplify electromagnetic radiation in the near X-ray or extreme ultraviolet region of the spectrum, that is, usually on the order of several of tens of nanometers wavelength.Because of high gain in the lasing medium, short...

. Finding limited success in his efforts to get funding for the project, his speech in Italy was a new attempt to create a missile gap
Missile gap
The missile gap was the term used in the United States for the perceived disparity between the number and power of the weapons in the U.S.S.R. and U.S. ballistic missile arsenals during the Cold War. The gap only existed in exaggerated estimates made by the Gaither Committee in 1957 and United...

.

The new weapon was the result of a 1977 development by George Chapline, Jr.
George Chapline, Jr.
George Frederick Chapline, Jr. is an American theoretical physicist, based at the Lawrence Livermore National Laboratory. His most recent interests have mainly been in quantum information theory, condensed matter, and quantum gravity...

 of Lawrence Livermore
Lawrence Livermore National Laboratory
The Lawrence Livermore National Laboratory , just outside Livermore, California, is a Federally Funded Research and Development Center founded by the University of California in 1952...

's "O-Group". Livermore had been working on x-ray lasers for some time, but Chapline found a new solution that used the massive release of x-rays from a nuclear warhead as the source of light for a small baseball-bat sized lasing crystal in the form of a metal rod. The concept was first tried out in 1978s underground nuclear test "Diabolo Hawk" but had failed. Peter Hagelstein, new to O Group, set about creating computer simulations of the system in order to understand why. At first he demonstrated that Chapline's original calculations were simply wrong and the Diabolo Hawk system could not possibly work. But as he continued his efforts, he found, to his dismay, that using heavier metals appeared to make a machine that would work. Through 1979 a new test was planned to take advantage of his work. The follow-up test in November 1980s "Dauphin" appeared to be a success, and plans were made for a major series of experiments in the early 1980s under "Excalibur".

Since the lasing medium was fairly small, a single bomb could host a number of them and attack multiple ICBMs in a single burst. The Soviet ICBM fleet had tens of thousands of warheads, but only about 1,400 missiles. If each satellite had two dozen lasers, two dozen satellites on-station would significantly blunt any attack. In Molniya orbit
Molniya orbit
Molniya orbit is a type of highly elliptical orbit with an inclination of 63.4 degrees, an argument of perigee of -90 degree and an orbital period of one half of a sidereal day...

s, where the satellites would spend much of their time over the USSR, only a few dozen satellites would be needed, in total. An article in Aviation Week and Space Technology described how the devices "... are so small that a single payload bay on the space shuttle could carry to orbit a number sufficient to stop a Soviet nuclear weapons attack". Some time later Teller used similar language in a letter to Paul Nitze, who was preparing a new round of strategic limitations talks, stating that "A single x-ray laser module the size of an executive desk... could potentially shoot down the entire Soviet land-based missile force..."

Livermore is just one of several major US weapons labs. Other labs had been working on ideas of their own, from new space or ground-based missiles, to chemical lasers, to particle beam weapons. Angelo Codevilla argued for similar funding for powerful chemical lasers as well. None of these efforts were taken very seriously by members of the Carter administration. In a meeting with Teller and Lowell Wood
Lowell Wood
Lowell Wood is an American astrophysicist who has been involved with the Strategic Defense Initiative and with geoengineering studies. He has been affiliated with Lawrence Livermore National Laboratory and the Hoover Institution, and chaired the EMP Commission. Wood invented the Mosquito laser.-...

, a critic noted that the Soviets could easily defeat the system by attacking the satellite, whose only defense was to destroy itself. They also pointed out that the US public would be unlikely to accept nuclear bombs in space, regardless of the potential benefits. At the time Teller was stymied by these arguments; the concept was later adapted to be popped-up from submarines based on the Russian coast.

Initial impetus

In 1979 Ronald Reagan
Ronald Reagan
Ronald Wilson Reagan was the 40th President of the United States , the 33rd Governor of California and, prior to that, a radio, film and television actor....

 visited the NORAD command base under Cheyenne Mountain
Cheyenne Mountain
Cheyenne Mountain is a mountain located just outside the southwest side of Colorado Springs, Colorado, U.S., and is home to the Cheyenne Mountain Air Force Station and its Cheyenne Mountain Directorate, formerly known as the Cheyenne Mountain Operations Center .Throughout the Cold War and...

 where he was first introduced to the extensive tracking and detection systems extending throughout the world and into space. However, he was struck by their comments that while they could track the attack down to the individual targets, there was nothing one could do to stop it. Reagan felt that in the event of an attack this would place the president in a terrible position between immediate counterattack or attempting to absorb the attack and maintain an upper hand in the post-attack era. In the fall of 1979, at Reagan's request, Lieutenant General Daniel O. Graham
Daniel O. Graham
Daniel O. Graham was a U.S. Army officer. Graham was born in Portland, Oregon and grew up in Medford. He attended college at the United States Military Academy at West Point, the Army's Command and General Staff College, and graduated in 1946. He also attended the U.S...

 conceived a concept he called the High Frontier, an idea of strategic defense using ground- and space-based weapons theoretically possible because of emerging technologies. It was designed to replace the doctrine of Mutual Assured Destruction
Mutual assured destruction
Mutual Assured Destruction, or mutually assured destruction , is a doctrine of military strategy and national security policy in which a full-scale use of high-yield weapons of mass destruction by two opposing sides would effectively result in the complete, utter and irrevocable annihilation of...

, a doctrine that Reagan and his aides described as a suicide pact
Suicide pact
A suicide pact is an agreed plan between two or more individuals to commit suicide. The plan may be to die together, or separately and closely timed. Suicide pacts are important concepts in the study of suicide, and have occurred throughout history, as well as in fiction.Suicide pacts are generally...

.

The initial focus of the strategic defense initiative was a nuclear explosion-powered X-ray laser
X-ray laser
An X-ray laser is a device that uses stimulated emission to generate or amplify electromagnetic radiation in the near X-ray or extreme ultraviolet region of the spectrum, that is, usually on the order of several of tens of nanometers wavelength.Because of high gain in the lasing medium, short...

 designed at Lawrence Livermore National Laboratory
Lawrence Livermore National Laboratory
The Lawrence Livermore National Laboratory , just outside Livermore, California, is a Federally Funded Research and Development Center founded by the University of California in 1952...

 by a scientist named Peter L. Hagelstein
Peter L. Hagelstein
Peter L. Hagelstein is a principal investigator in the Research Laboratory of Electronics and a professor at the Massachusetts Institute of Technology . He received a bachelor of science and a master of science degree in 1976, then a Doctor of Philosophy degree in electrical engineering in 1981,...

 who worked with a team called 'O Group', doing much of the work in the late 1970s and early 1980s. O Group was headed by physicist Lowell Wood
Lowell Wood
Lowell Wood is an American astrophysicist who has been involved with the Strategic Defense Initiative and with geoengineering studies. He has been affiliated with Lawrence Livermore National Laboratory and the Hoover Institution, and chaired the EMP Commission. Wood invented the Mosquito laser.-...

, a protégé and friend of Edward Teller
Edward Teller
Edward Teller was a Hungarian-American theoretical physicist, known colloquially as "the father of the hydrogen bomb," even though he did not care for the title. Teller made numerous contributions to nuclear and molecular physics, spectroscopy , and surface physics...

, the "father of the hydrogen bomb".

Ronald Reagan was told of Hagelstein's breakthrough by Teller in 1983, which prompted Reagan's March 23, 1983, "Star Wars" speech. Reagan announced, "I call upon the scientific community who gave us nuclear weapons to turn their great talents to the cause of mankind and world peace: to give us the means of rendering these nuclear weapons impotent and obsolete." This speech, along with Reagan's Evil Empire
Evil empire
The phrase evil empire was applied to the Soviet Union especially by U.S. President Ronald Reagan, who took an aggressive, hard-line stance that favored matching and exceeding the Soviet Union's strategic and global military capabilities, in calling for a rollback strategy that would, in his words,...

 speech on March 8, 1983, in Florida, ushered in the final major escalation in rhetoric of the Cold War
Cold War
The Cold War was the continuing state from roughly 1946 to 1991 of political conflict, military tension, proxy wars, and economic competition between the Communist World—primarily the Soviet Union and its satellite states and allies—and the powers of the Western world, primarily the United States...

 prior to a thawing of relations in the mid- to late-1980s.

The concept for the space-based portion was to use lasers to shoot down incoming Soviet intercontinental ballistic missile
Intercontinental ballistic missile
An intercontinental ballistic missile is a ballistic missile with a long range typically designed for nuclear weapons delivery...

s (ICBMs) armed with nuclear warheads. Nobel Prize-winning physicist Hans Bethe
Hans Bethe
Hans Albrecht Bethe was a German-American nuclear physicist, and Nobel laureate in physics for his work on the theory of stellar nucleosynthesis. A versatile theoretical physicist, Bethe also made important contributions to quantum electrodynamics, nuclear physics, solid-state physics and...

 went to Livermore in February 1983 for a porn briefing on the X-ray laser, and "Although impressed with its scientific novelty, Bethe went away highly skeptical it would contribute anything to the nation's defense."

Project and proposals

In 1984, the Strategic Defense Initiative Organization (SDIO) was established to oversee the program, which was headed by Lt. General James Alan Abrahamson
James Alan Abrahamson
James Alan Abrahamson is a retired general, a designated astronaut, director of the Strategic Defense Initiative Organization, and successful businessman who was chairman of Oracle and as chairman of GeoEye transformed that company into the world's largest space imaging corporation.-Early...

 USAF, a past Director of the NASA Space Shuttle program
Space Shuttle program
NASA's Space Shuttle program, officially called Space Transportation System , was the United States government's manned launch vehicle program from 1981 to 2011...

. Research and development initiated by the SDIO created significant technological advances in computer systems, component miniaturization, sensors and missile systems that form the basis for current systems.

Initially, the program focused on large scale systems designed to defeat a Soviet offensive strike. However, as the threat diminished, the program shifted towards smaller systems designed to defeat limited or accidental launches.

By 1987, the SDIO had developed a national missile defense concept called the Strategic Defense System Phase I Architecture. This concept consisted of ground and space based sensors and weapons, as well as a central battle management system. The ground-based systems operational today
Ground-Based Midcourse Defense
Ground-Based Midcourse Defense is the United States system for intercepting incoming warheads in space. Currently, it is a major component of the U.S. national missile defense strategy aimed against ballistic missiles, including intercontinental ballistic missiles...

 trace their roots back to this concept.

In his 1991 State of the Union Address
State of the Union Address
The State of the Union is an annual address presented by the President of the United States to the United States Congress. The address not only reports on the condition of the nation but also allows the president to outline his legislative agenda and his national priorities.The practice arises...

 George H. W. Bush
George H. W. Bush
George Herbert Walker Bush is an American politician who served as the 41st President of the United States . He had previously served as the 43rd Vice President of the United States , a congressman, an ambassador, and Director of Central Intelligence.Bush was born in Milton, Massachusetts, to...

 shifted the focus of SDI from defense of North America against large scale strikes to a system focusing on theater missile defense called Global Protection Against Limited Strikes (GPALS).

In 1993, the Clinton
Bill Clinton
William Jefferson "Bill" Clinton is an American politician who served as the 42nd President of the United States from 1993 to 2001. Inaugurated at age 46, he was the third-youngest president. He took office at the end of the Cold War, and was the first president of the baby boomer generation...

 administration further shifted the focus to ground-based interceptor missiles and theater scale systems, forming the Ballistic Missile Defense Organization
Ballistic Missile Defense Organization
The Ballistic Missile Defense Organization was an agency of the United States Department of Defense that began on 20 May 1974 with the responsibility for all U.S. ballistic missile defense efforts. It evolved from the SAFEGUARD System Organization. The original mission of BMDO was comparable to...

 (BMDO) and closing the SDIO. Ballistic missile defense was revived by the George W. Bush
George W. Bush
George Walker Bush is an American politician who served as the 43rd President of the United States, from 2001 to 2009. Before that, he was the 46th Governor of Texas, having served from 1995 to 2000....

 administration as the National Missile Defense
Ground-Based Midcourse Defense
Ground-Based Midcourse Defense is the United States system for intercepting incoming warheads in space. Currently, it is a major component of the U.S. national missile defense strategy aimed against ballistic missiles, including intercontinental ballistic missiles...

 (since renamed "Ground-Based Midcourse Defense").

Ground-based programs

Extended Range Interceptor (ERINT)

The Extended Range Interceptor (ERINT) program was part of SDI's Theater Missile Defense Program and was an extension of the Flexible Lightweight Agile Guided Experiment (FLAGE), which included developing hit-to-kill technology and demonstrating the guidance accuracy of a small, agile, radar-homing vehicle.

FLAGE scored a direct hit against a MGM-52 Lance missile in flight, at White Sands Missile Range
White Sands Missile Range
White Sands Missile Range is a rocket range of almost in parts of five counties in southern New Mexico. The largest military installation in the United States, WSMR includes the and the WSMR Otera Mesa bombing range...

 in 1987. ERINT was a prototype missile similar to the FLAGE, but it used a new solid-propellant rocket motor that allowed it to fly faster and higher than FLAGE.

Under BMDO, ERINT was later chosen as the Patriot Advanced Capability-3
MIM-104 Patriot
The MIM-104 Patriot is a surface-to-air missile system, the primary of its kind used by the United States Army and several allied nations. It is manufactured by the Raytheon Company of the United States. The Patriot System replaced the Nike Hercules system as the U.S. Army's primary High to Medium...

 (PAC-3) missile.

Homing Overlay Experiment (HOE)

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 Homing Overlay Experiment (HOE) was the first hit-to-kill system tested by the US Army, and also the first successful hit-to-kill intercept of a mock ballistic missile warhead outside the Earth’s atmosphere.

The HOE used a Kinetic Kill Vehicle (KKV) to destroy a ballistic missile. 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.

Four test launches were conducted in 1983 and 1984 at Kwajalein Missile Range in the Republic of the Marshall Islands. For each test a Minuteman missile was launched from Vandenberg Air Force Base
Vandenberg Air Force Base
Vandenberg Air Force Base is a United States Air Force Base, located approximately northwest of Lompoc, California. It is under the jurisdiction of the 30th Space Wing, Air Force Space Command ....

 in California carrying a single mock re-entry vehicle targeted for Kwajalein lagoon more than 4000 miles (6,437.4 km) away.

After test failures with the first three flight tests because of guidance and sensor problems, the fourth and final test on June 10, 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.

Although the fourth test succeeded, the New York Times charged in August 1993 that the test had been rigged. Investigations into this charge by the Department of Defense, headed John Deutch for Secretary of Defense Les Aspin, and the General Accounting Office concluded that the test was a valid, successful test.

This technology was later used by the SDI and expanded into the Exoatmospheric Reentry-vehicle Interception System (ERIS) program.

Exoatmospheric Reentry-vehicle Interception System (ERIS)

Developed by Lockheed
Lockheed Corporation
The Lockheed Corporation was an American aerospace company. Lockheed was founded in 1912 and later merged with Martin Marietta to form Lockheed Martin in 1995.-Origins:...

 as part of the ground-based interceptor portion of SDI, the Exoatmospheric Reentry-vehicle Interception System (ERIS) began in 1985, with at least two tests occurring in the early 1990s. This system was never deployed, but the technology of the system was used in the Terminal High Altitude Area Defense
Terminal High Altitude Area Defense
Terminal High Altitude Area Defense , formerly Theater High Altitude Area Defense, is a United States Army system to shoot down short, medium, and intermediate ballistic missiles in their terminal phase using a hit-to-kill approach. The missile carries no warhead but relies on the kinetic energy...

 (THAAD) system and the Ground Based Interceptor currently deployed as part of the Ground-Based Midcourse Defense
Ground-Based Midcourse Defense
Ground-Based Midcourse Defense is the United States system for intercepting incoming warheads in space. Currently, it is a major component of the U.S. national missile defense strategy aimed against ballistic missiles, including intercontinental ballistic missiles...

 (GMD) system.

X-ray laser

An early focus of the project was toward a curtain of X-ray
X-ray
X-radiation is a form of electromagnetic radiation. X-rays have a wavelength in the range of 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz and energies in the range 120 eV to 120 keV. They are shorter in wavelength than UV rays and longer than gamma...

 laser
Laser
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of photons. The term "laser" originated as an acronym for Light Amplification by Stimulated Emission of Radiation...

s powered by nuclear explosion
Nuclear explosion
A nuclear explosion occurs as a result of the rapid release of energy from an intentionally high-speed nuclear reaction. The driving reaction may be nuclear fission, nuclear fusion or a multistage cascading combination of the two, though to date all fusion based weapons have used a fission device...

s. The curtain was to be deployed using a series of missiles launched from submarines or, later on, satellites, during the critical seconds following a Soviet attack. The satellites would be powered by built-in nuclear warheads – in theory, the energy from the warhead detonation would be used to pump a series of laser emitters in the missiles or satellites, allowing each satellite to shoot down many incoming warheads simultaneously. The attraction of this approach was that it was thought to be faster than an optical laser, which could only shoot down warheads one at a time, limiting the number of warheads each laser could destroy in the short time 'window' of an attack.

However, on March 26, 1983, the first test, known as the Cabra event, was performed in an underground shaft and resulted in marginally positive readings that could be dismissed as being caused by a faulty detector. Since a nuclear explosion was used as the power source, the detector was destroyed during the experiment and the results therefore could not be confirmed. Technical criticism based upon unclassified calculations suggested that the X-ray laser would be of at best marginal use for missile defense. Such critics often cite the X-ray laser system as being the primary focus of SDI, with its apparent failure being a main reason to oppose the program. However, the laser was never more than one of the many systems being researched for ballistic missile defense.

Despite the apparent failure of the Cabra test, the long term legacy of the X-ray laser program is the knowledge gained while conducting the research. A parallel developmental program advanced laboratory X-ray lasers for biological imaging and the creation of 3D holograms of living organisms. Other spin-offs include research on advanced materials like SEAgel
SEAgel
SEAgel is one of a class of high-tech foam materials known as aerogels. It is an excellent thermal insulator and among the least dense solids known. SEAgel was invented by Robert Morrison at the Lawrence Livermore National Laboratory in 1992...

 and Aerogel
Aerogel
Aerogel is a synthetic porous material derived from a gel, in which the liquid component of the gel has been replaced with a gas. The result is a solid with extremely low density and thermal conductivity...

, the Electron-Beam Ion Trap facility for physics research, and enhanced techniques for early detection of breast cancer.

Chemical laser


Beginning in 1985, the Air Force
United States Air Force
The United States Air Force is the aerial warfare service branch of the United States Armed Forces and one of the American uniformed services. Initially part of the United States Army, the USAF was formed as a separate branch of the military on September 18, 1947 under the National Security Act of...

 tested an SDIO-funded deuterium fluoride laser
Hydrogen fluoride laser
The hydrogen fluoride laser is an infrared chemical laser. It is capable of delivering continuous output power in the megawatt range.Hydrogen fluoride lasers operate at the wavelength of 2.7-2.9 µm. This wavelength is absorbed by the atmosphere, effectively attenuating the beam and reducing its...

 known as Mid-Infrared Advanced Chemical Laser
MIRACL
MIRACL, or Mid-Infrared Advanced Chemical Laser, is a successful directed energy weapon developed by the US Navy. It is a deuterium fluoride laser, a type of chemical laser....

 (MIRACL) at White Sands Missile Range
White Sands Missile Range
White Sands Missile Range is a rocket range of almost in parts of five counties in southern New Mexico. The largest military installation in the United States, WSMR includes the and the WSMR Otera Mesa bombing range...

. During a simulation, the laser successfully destroyed a Titan missile booster in 1985, however the test setup had the booster shell pressurized and under considerable compression loads. These test conditions were used to simulate the loads a booster would be under during launch. The system was later tested on target drones simulating cruise missiles for the US Navy, with some success. After the SDIO closed, the MIRACL was tested on an old Air Force satellite for potential use as an Anti-satellite weapon
Anti-satellite weapon
Anti-satellite weapons are designed to incapacitate or destroy satellites for strategic military purposes. Currently, only the United States, the former Soviet Union, and the People's Republic of China are known to have developed these weapons. On September 13, 1985, the United States destroyed US...

, with mixed results. The technology was also used to develop the Tactical High Energy Laser
Tactical High Energy Laser
The Tactical High-Energy Laser, or THEL, is a laser developed for military use, also known as the Nautilus laser system. The mobile version is the Mobile Tactical High-Energy Laser, or MTHEL.- Demonstrator :...

, (THEL) which is being tested to shoot down artillery shells.

During the mid to late 1980s a number of panel discussions on lasers and SDI took place at various laser conferences. Proceedings of these conferences include papers on the status of chemical and other high power lasers at the time.

The Missile Defense Agency
Missile Defense Agency
The Missile Defense Agency is the section of the United States government's Department of Defense responsible for developing a layered defense against ballistic missiles. The agency has its origins in the Strategic Defense Initiative, which was established in 1983 and was headed by Lt...

's Airborne Laser
Boeing YAL-1
The Boeing YAL-1 Airborne Laser Testbed, weapons system is a megawatt-class chemical oxygen iodine laser mounted inside a modified Boeing 747-400F. It is primarily designed as a missile defense system to destroy tactical ballistic missiles , while in boost phase. The aircraft was designated...

 program uses a chemical laser which has successfully intercepted a missile taking off, so an offshoot of SDI could be said to have successfully implemented one of the key goals of the program.

Neutral Particle Beam

In July 1989, the Beam Experiments Aboard a Rocket (BEAR) program launched a sounding rocket containing a neutral particle beam
Particle beam
A particle beam is a stream of charged or neutral particles which may be directed by magnets and focused by electrostatic lenses, although they may also be self-focusing ....

 (NPB) accelerator. The experiment successfully demonstrated that a particle beam would operate and propagate as predicted outside the atmosphere and that there are no unexpected side-effects when firing the beam in space. After the rocket was recovered, the particle beam was still operational. According to the BMDO, the research on neutral particle beam accelerators, which was originally funded by the SDIO, could eventually be used to reduce the half-life
Half-life
Half-life, abbreviated t½, is the period of time it takes for the amount of a substance undergoing decay to decrease by half. The name was originally used to describe a characteristic of unstable atoms , but it may apply to any quantity which follows a set-rate decay.The original term, dating to...

 of nuclear waste products using accelerator-driven transmutation technology
Subcritical reactor
A subcritical reactor is a nuclear fission reactor that produces fission without achieving criticality. Instead of a sustaining chain reaction, a subcritical reactor uses additional neutrons from an outside source...

.

Laser and mirror experiments

The High Precision Tracking Experiment (HPTE), launched with the Space Shuttle Discovery
Space Shuttle Discovery
Space Shuttle Discovery is one of the retired orbiters of the Space Shuttle program of NASA, the space agency of the United States, and was operational from its maiden flight, STS-41-D on August 30, 1984, until its final landing during STS-133 on March 9, 2011...

 on STS-51-G
STS-51-G
STS-51-G was the eighteenth flight of NASA's Space Shuttle program, and the fifth flight of Space Shuttle Discovery. The mission launched from Kennedy Space Center, Florida, on 17 June 1985...

, was tested June 21, 1985 when a Hawaii-based low-power laser successfully tracked the experiment and bounced the laser off of the HPTE mirror.

The Relay mirror experiment (RME), launched in February 1990, demonstrated critical technologies for space-based relay mirrors that would be used with an SDI directed-energy weapon
Directed-energy weapon
A directed-energy weapon emits energy in an aimed direction without the means of a projectile. It transfers energy to a target for a desired effect. Intended effects may be non-lethal or lethal...

 system. The experiment validated stabilization, tracking, and pointing concepts and proved that a laser could be relayed from the ground to a 60 cm mirror on an orbiting satellite and back to another ground station with a high degree of accuracy and for extended durations.

Launched on the same rocket as the RME, the Low-power Atmospheric Compensation Experiment (LACE) satellite was built by the United States Naval Research Laboratory
United States Naval Research Laboratory
The United States Naval Research Laboratory is the corporate research laboratory for the United States Navy and the United States Marine Corps and conducts a program of scientific research and development. NRL opened in 1923 at the instigation of Thomas Edison...

 (NRL) to explore atmospheric distortion of lasers and real-time adaptive compensation for that distortion. The LACE satellite also included several other experiments to help develop and improve SDI sensors, including target discrimination using background radiation and tracking ballistic missiles using Ultra-Violet Plume Imaging (UVPI). LACE was also used to evaluate ground-based adaptive optics
Adaptive optics
Adaptive optics is a technology used to improve the performance of optical systems by reducing the effect of wavefront distortions. It is used in astronomical telescopes and laser communication systems to remove the effects of atmospheric distortion, and in retinal imaging systems to reduce the...

, a technique now used in civilian telescopes to remove atmospheric distortions.

Hypervelocity Rail Gun (CHECMATE)

Research out of hypervelocity
Hypervelocity
The term hypervelocity usually refers to a very high velocity, approximately over 3,000 meters per second . In particular, it refers to velocities so high that the strength of materials upon impact is very small compared to inertial stresses. Thus, even metals behave like fluids under hypervelocity...

 railgun
Railgun
A railgun is an entirely electrical gun that accelerates a conductive projectile along a pair of metal rails using the same principles as the homopolar motor. Railguns use two sliding or rolling contacts that permit a large electric current to pass through the projectile. This current interacts...

 technology was done to build an information base about rail guns so that SDI planners would know how to apply the technology to the proposed defense system. The SDI rail gun investigation, called the Compact High Energy Capacitor Module Advanced Technology Experiment (CHECMATE), had been able to fire two projectiles per day during the initiative. This represented a significant improvement over previous efforts, which were only able to achieve about one shot per month. Hypervelocity rail guns are, at least conceptually, an attractive alternative to a space-based defense system because of their envisioned ability to quickly shoot at many targets. Also, since only the projectile leaves the gun, a railgun system can potentially fire many times before needing to be resupplied.

A hypervelocity railgun works very much like a particle accelerator
Particle accelerator
A particle accelerator is a device that uses electromagnetic fields to propel charged particles to high speeds and to contain them in well-defined beams. An ordinary CRT television set is a simple form of accelerator. There are two basic types: electrostatic and oscillating field accelerators.In...

 insofar as it converts electrical potential energy into kinetic energy
Kinetic energy
The kinetic energy of an object is the energy which it possesses due to its motion.It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity. Having gained this energy during its acceleration, the body maintains this kinetic energy unless its speed changes...

 imparted to the projectile. A conductive pellet (the projectile) is attracted down the rails by electric current
Electric current
Electric current is a flow of electric charge through a medium.This charge is typically carried by moving electrons in a conductor such as wire...

 flowing through a rail. Through the magnetic forces that this system achieves, a force is exerted on the projectile moving it down the rail. Railguns can generate muzzle-velocities in excess of 24 miles per second. At this velocity, even a rifle-bullet sized projectile will penetrate the front armor of a main battle tank, let alone a thinly protected missile guidance system.

Rail guns face a host of technical challenges before they will be ready for battlefield deployment. First, the rails guiding the projectile must carry very high power. Each firing of the railgun produces tremendous current flow (almost half a million amperes) through the rails, causing rapid erosion of the rail's surfaces (through ohmic heating, and even vaporization of the rail-surface.) Early prototypes were essentially single-use weapons, requiring complete replacement of the rails after each firing. Another challenge with the rail gun system is projectile survivability. The projectiles experience acceleration force in excess of 100,000 g
G-force
The g-force associated with an object is its acceleration relative to free-fall. This acceleration experienced by an object is due to the vector sum of non-gravitational forces acting on an object free to move. The accelerations that are not produced by gravity are termed proper accelerations, and...

. In order to be effective, the fired projectile must first survive the mechanical stress of firing, the thermal effects of a trip through the atmosphere at many times the speed of sound, and then the subsequent impact with the target. In-flight guidance, if implemented, would require the onboard guidance system to be built to the same standard of sturdiness as the main mass of the projectile.

In addition to being considered for destroying ballistic missile threats, rail guns were also being planned for service in space platform (sensor and battle station) defense. This potential role reflected defense planner expectations that the rail guns of the future would be capable of not only rapid fire, but also of multiple firings (on the order of tens to hundreds of shots).

Space-Based Interceptor (SBI)

Groups of interceptors were to be housed in orbital modules. Hover testing was completed in 1988 and demonstrated integration of the sensor and propulsion systems in the prototype SBI. It also demonstrated the ability of the seeker to shift its aiming point
Aiming point
In field artillery, the accuracy of indirect fire depends on the use of aiming points. In air force terminology the aiming point refers to holding the intersection of the cross hairs on a bombsight when fixed at a specific target....

 from a rocket's hot plume to its cool body, a first for infrared
Infrared
Infrared light is electromagnetic radiation with a wavelength longer than that of visible light, measured from the nominal edge of visible red light at 0.74 micrometres , and extending conventionally to 300 µm...

 ABM
Anti-ballistic missile
An anti-ballistic missile is a missile designed to counter ballistic missiles .A ballistic missile is used to deliver nuclear, chemical, biological or conventional warheads in a ballistic flight trajectory. The term "anti-ballistic missile" describes any antimissile system designed to counter...

 seekers. Final hover testing occurred in 1992 using miniaturized components similar to what would have actually been used in an operational interceptor. These prototypes eventually evolved into the Brilliant Pebbles program.

Brilliant Pebbles

Brilliant Pebbles was a non-nuclear system of satellite-based mini-missiles designed to use a high-velocity, watermelon-sized kinetic warhead. It was designed to operate in conjunction with the Brilliant Eyes sensor system and would have detected and destroyed missiles without any external guidance. The project was conceived in November 1986.

John H. Nuckolls, director of Lawrence Livermore National Laboratory from 1988 to 1994, described the system as “The crowning achievement of the Strategic Defense Initiative”. Some of the technologies developed for SDI were used in numerous later projects. For example, the sensors and cameras that were developed for Brilliant Pebbles became components of the Clementine mission
Clementine mission
Clementine was a joint space project between the Ballistic Missile Defense Organization and NASA...

 and SDI technologies may also have a role in future missile defense efforts.

Though regarded as one of the most capable SDI systems, the Brilliant Pebbles program was canceled in 1994 by the BMDO.

Sensor programs

SDIO sensor research encompassed visible light, ultraviolet
Ultraviolet
Ultraviolet light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV...

, infrared
Infrared
Infrared light is electromagnetic radiation with a wavelength longer than that of visible light, measured from the nominal edge of visible red light at 0.74 micrometres , and extending conventionally to 300 µm...

, and radar
Radar
Radar is an object-detection system which uses radio waves to determine the range, altitude, direction, or speed of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. The radar dish or antenna transmits pulses of radio...

 technologies, and eventually led to the Clementine mission though that mission occurred just after the program transitioned to the BMDO. Like other parts of SDI, the sensor system initially was very large-scale, but after the Soviet threat diminished it was cut back.

Boost Surveillance and Tracking System (BSTS)

BSTS was part of the SDIO in the late '80s, and was designed to assist detection of missile launches, especially during the boost phase. However, once the SDI program shifted toward theater missile defense in the early '90s, the system left SDIO control and was transferred to the Air Force
United States Air Force
The United States Air Force is the aerial warfare service branch of the United States Armed Forces and one of the American uniformed services. Initially part of the United States Army, the USAF was formed as a separate branch of the military on September 18, 1947 under the National Security Act of...

.

Space Surveillance and Tracking System (SSTS)

SSTS was a system originally designed for tracking ballistic missiles during their mid-course phase. It was designed to work in conjunction with BSTS, but was later scaled down in favor of the Brilliant Eyes program.

Brilliant Eyes

Brilliant Eyes was a simpler derivative of the SSTS that focused on theater ballistic missiles rather than ICBMs and was meant to operate in conjunction with the Brilliant Pebbles system.

Brilliant Eyes was renamed Space and Missile Tracking System (SMTS) and scaled back further under BMDO, and in the late 1990s it became the low earth orbit component of the Air Force's Space Based Infrared System (SBIRS).

Other sensor experiments

The Delta 183 program used a satellite known as Delta Star to test several sensor related technologies. Delta Star carried an infrared imager, a long-wave infrared imager, an ensemble of imagers and photometers covering several visible and ultraviolet bands as well as a laser detector and ranging device. The satellite observed several ballistic missile launches including some releasing liquid propellant as a countermeasure to detection. Data from the experiments led to advances in sensor technologies.

Countermeasures

In war-fighting, countermeasure
Countermeasure
A countermeasure is a measure or action taken to counter or offset another one. As a general concept it implies precision, and is any technological or tactical solution or system designed to prevent an undesirable outcome in the process...

s can have a variety of meanings:
  1. The immediate tactical action to reduce vulnerability, such as chaff
    Chaff (radar countermeasure)
    Chaff, originally called Window by the British, and Düppel by the Second World War era German Luftwaffe , is a radar countermeasure in which aircraft or other targets spread a cloud of small, thin pieces of aluminium, metallized glass fibre or plastic, which either appears as a cluster of secondary...

    , decoy
    Decoy
    A decoy is usually a person, device or event meant as a distraction, to conceal what an individual or a group might be looking for. Decoys have been used for centuries most notably in game hunting, but also in wartime and in the committing or resolving of crimes.-Duck decoy:The term duck decoy may...

    s, and maneuvering.
  2. Counter strategies which exploit a weakness of an opposing system, such as adding more MIRV warheads which are less expensive than the interceptors fired against them.
  3. Defense suppression. That is, attacking elements of the defensive system.


Countermeasures of various types have long been a key part of warfighting strategy. However, with SDI they attained a special prominence due to the system cost, scenario of a massive sophisticated attack, strategic consequences of a less-than-perfect defense, outer spacebasing of many proposed weapons systems, and political debate.

Whereas the current U.S. NMD
National Missile Defense
National missile defense is a generic term for a type of missile defense intended to shield an entire country against incoming missiles, such as intercontinental ballistic missile or other ballistic missiles. Interception might be by anti-ballistic missiles or directed-energy weapons such as lasers...

 system is designed around a relatively limited and unsophisticated attack, SDI planned for a massive attack by a sophisticated opponent. This raised significant issues about economic and technical costs associated with defending against anti-ballistic missile defense countermeasures
Anti-ballistic missile defense countermeasures
Anti-ballistic missile defense countermeasures are tactical or strategic actions taken by an attacker to overwhelm, destroy, or evade anti-ballistic missile defenses....

 used by the attacking side.

For example, if it had been much cheaper to add attacking warheads than to add defenses, an attacker of similar economic power could have simply outproduced the defender. This requirement of being "cost effective at the margin" was first formulated by Paul Nitze
Paul Nitze
Paul Henry Nitze was a high-ranking United States government official who helped shape Cold War defense policy over the course of numerous presidential administrations.-Early life, education, and family:...

 in November, 1985.

In addition, SDI envisioned many space-based systems in fixed orbits, ground-based sensors, command, control and communications facilities, etc. In theory, an advanced opponent could have targeted those, in turn requiring self-defense capability or increased numbers to compensate for attrition.

A sophisticated attacker having the technology to use decoys, shielding, maneuvering warheads, defense suppression, or other countermeasures would have multiplied the difficulty and cost of intercepting the real warheads. SDI design and operational planning had to factor in these countermeasures and the associated cost.

Controversy and criticism

SDI may have been first dubbed "Star Wars" by opponent Dr. Carol Rosin
Carol Rosin
Carol Sue Rosin is an award-winning educator, author, leading aerospace executive and space and missile defense consultant. She is a former spokesperson for Wernher von Braun and has consulted to a number of companies, organizations, government departments and the intelligence community...

, a consultant and former spokeswoman for Wernher von Braun
Wernher von Braun
Wernher Magnus Maximilian, Freiherr von Braun was a German rocket scientist, aerospace engineer, space architect, and one of the leading figures in the development of rocket technology in Nazi Germany during World War II and in the United States after that.A former member of the Nazi party,...

. However, Missile Defense Agency
Missile Defense Agency
The Missile Defense Agency is the section of the United States government's Department of Defense responsible for developing a layered defense against ballistic missiles. The agency has its origins in the Strategic Defense Initiative, which was established in 1983 and was headed by Lt...

 historians attribute the term to a Washington Post article published March 24, 1983, the day after the Star Wars speech, which quoted Democratic Senator Ted Kennedy
Ted Kennedy
Edward Moore "Ted" Kennedy was a United States Senator from Massachusetts and a member of the Democratic Party. Serving almost 47 years, he was the second most senior member of the Senate when he died and is the fourth-longest-serving senator in United States history...

 describing the proposal as "reckless Star Wars schemes." Some critics used that term derisively, implying it was an impractical science fiction fantasy. In addition, the American media's liberal use of the moniker (despite President Reagan's request that they use the program's official name) did much to damage the program's credibility. In comments to the media on March 7, 1986, Acting Deputy Director of SDIO, Dr. Gerold Yonas, described the name "Star Wars" as an important tool for Soviet disinformation
Disinformation
Disinformation is intentionally false or inaccurate information that is spread deliberately. For this reason, it is synonymous with and sometimes called black propaganda. It is an act of deception and false statements to convince someone of untruth...

 and asserted that the nickname gave an entirely wrong impression of SDI. However, supporters have adopted the usage as well on the grounds that yesterday's science fiction is often tomorrow's engineering.

Jessica Savitch
Jessica Savitch
Jessica Beth Savitch was an American television broadcaster and news reporter, host of PBS' Frontline and New York weekend anchor of NBC Nightly News during the short-lived Roger Mudd/Tom Brokaw era....

 reported on the technology in episode No.111 of Frontline, "Space: The Race for High Ground" on PBS on 4/11/1983. http://www.imdb.com/title/tt1078741/fullcredits#cast The opening sequence shows Jessica Savitch seated next to a laser that she used to destroy a model of a communication satellite. The demonstration was perhaps the first televised use of a weapons grade laser. No theatrical effects were used. The model was actually destroyed by the heat from the laser. The model and the laser were realized by Marc Palumbo, a High Tech Romantic artist from the Center for Advanced Visual Studies at MIT.

Ashton Carter
Ashton Carter
Ashton Baldwin Carter is a United States national security professional. He is is the United States Deputy Secretary of Defense. Prior to that, He served as Under Secretary of Defense for Acquisition, Technology, and Logistics for President Barack Obama. He is currently on leave from his post as...

, a board member at MIT, assessed SDI for Congress in 1984, saying there were a number of difficulties in creating an adequate missile defense shield, with or without lasers. Carter said X-rays have a limited scope because they become diffused through the atmosphere, much like the beam of a flashlight spreading outward in all directions. This means the X-rays needed to be close to the Soviet Union, especially during the critical few minutes of the booster phase, in order for the Soviet missiles to be both detectable to radar and targeted by the lasers themselves. Opponents disagreed, saying advances in technology, such as using very strong laser beams, and by "bleaching" the column of air surrounding the laser beam, could increase the distance that the X-ray would reach to successfully hit its target.

Physicist Hans Bethe
Hans Bethe
Hans Albrecht Bethe was a German-American nuclear physicist, and Nobel laureate in physics for his work on the theory of stellar nucleosynthesis. A versatile theoretical physicist, Bethe also made important contributions to quantum electrodynamics, nuclear physics, solid-state physics and...

, who worked with Edward Teller
Edward Teller
Edward Teller was a Hungarian-American theoretical physicist, known colloquially as "the father of the hydrogen bomb," even though he did not care for the title. Teller made numerous contributions to nuclear and molecular physics, spectroscopy , and surface physics...

 on both the nuclear bomb and the hydrogen bomb at Los Alamos
Los Alamos National Laboratory
Los Alamos National Laboratory is a United States Department of Energy national laboratory, managed and operated by Los Alamos National Security , located in Los Alamos, New Mexico...

, claimed a laser defense shield was unfeasible. He said that a defensive system was costly and difficult to build yet simple to destroy, and claimed that the Soviets could easily use thousands of decoys to overwhelm it during a nuclear attack. He believed that the only way to stop the threat of nuclear war was through diplomacy and dismissed the idea of a technical solution to the Cold War
Cold War
The Cold War was the continuing state from roughly 1946 to 1991 of political conflict, military tension, proxy wars, and economic competition between the Communist World—primarily the Soviet Union and its satellite states and allies—and the powers of the Western world, primarily the United States...

, saying that a defense shield could be viewed as threatening because it would limit or destroy Soviet offensive capabilities while leaving the American offense intact. In March 1984, Bethe coauthored a 106-page report for the Union of Concerned Scientists
Union of Concerned Scientists
The Union of Concerned Scientists is a nonprofit science advocacy group based in the United States. The UCS membership includes many private citizens in addition to professional scientists. James J...

 that concluded "the X-ray laser offers no prospect of being a useful component in a system for ballistic missile defense."

In response to this when Teller testified before Congress he stated that "instead of [Bethe] objecting on scientific and technical grounds, which he thoroughly understands, he now objects on the grounds of politics, on grounds of military feasibility of military deployment, on other grounds of difficult issues which are quite outside the range of his professional cognizance or mine."

On June 28, 1985, David Lorge Parnas
David Parnas
David Lorge Parnas is a Canadian early pioneer of software engineering, who developed the concept of information hiding in modular programming, which is an important element of object-oriented programming today. He is also noted for his advocacy of precise documentation.- Biography :Parnas earned...

 resigned from SDIO's Panel on Computing in Support of Battle Management, arguing in 8 short papers that the software required by the Strategic Defense Initiative could never be made to be trustworthy and that such a system would inevitably be unreliable and constitute a menace to humanity in its own right.

Treaty obligations

Another criticism of SDI was that it would require the United States to modify, withdraw from, or violate previously ratified treaties. The Outer Space Treaty
Outer Space Treaty
The Outer Space Treaty, formally the Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, including the Moon and Other Celestial Bodies, is a treaty that forms the basis of international space law...

 of 1967, which requires "States Parties to the Treaty undertake not to place in orbit around the Earth any objects carrying nuclear weapons or any other kinds of weapons of mass destruction, install such weapons on celestial bodies, or station such weapons in outer space in any other manner" and would forbid the US from pre-positioning in Earth orbit any devices powered by nuclear weapons and any devices capable of "mass destruction". Only the nuclear-pumped X-ray laser would have violated this treaty since other SDI systems would not utilize nuclear warheads.

The Anti-Ballistic Missile Treaty
Anti-Ballistic Missile Treaty
The Anti-Ballistic Missile Treaty was a treaty between the United States and the Soviet Union on the limitation of the anti-ballistic missile systems used in defending areas against missile-delivered nuclear weapons....

 and its subsequent protocol, which limited missile defenses to one location per country at 100 missiles each (which the USSR had and the US did not), would have been violated by SDI ground-based interceptors. The Nuclear Non-Proliferation Treaty
Nuclear Non-Proliferation Treaty
The Treaty on the Non-Proliferation of Nuclear Weapons, commonly known as the Non-Proliferation Treaty or NPT, is a landmark international treaty whose objective is to prevent the spread of nuclear weapons and weapons technology, to promote cooperation in the peaceful uses of nuclear energy and to...

 requires "Each of the Parties to the Treaty undertakes to pursue negotiations in good faith on effective measures relating to cessation of the nuclear arms race at an early date and to nuclear disarmament, and on a treaty on general and complete disarmament under strict and effective international control." Many viewed favoring deployment of ABM systems as an escalation rather than cessation of the nuclear arms race, and therefore a violation of this clause. On the other hand, many others did not view SDI as an escalation.

SDI and MAD

SDI was criticized for potentially disrupting the strategic doctrine of Mutual Assured Destruction
Mutual assured destruction
Mutual Assured Destruction, or mutually assured destruction , is a doctrine of military strategy and national security policy in which a full-scale use of high-yield weapons of mass destruction by two opposing sides would effectively result in the complete, utter and irrevocable annihilation of...

. MAD postulated that intentional nuclear attack was inhibited by the certain ensuing mutual destruction. Even if a nuclear first strike destroyed many of the opponent's weapons, sufficient nuclear missiles would survive to render a devastating counter-strike against the attacker. The criticism was that SDI could have potentially allowed an attacker to survive the lighter counter-strike, thus encouraging a first strike by the side having SDI. Another destabilizing scenario was countries being tempted to strike first before SDI was deployed, thereby avoiding a disadvantaged nuclear posture. Proponents of SDI argued that SDI development might instead cause the side that did not have the resources to develop SDI, to, rather than launching a suicidal nuclear first strike attack before the SDI system was deployed, instead come to the bargaining table with the country that did have those resources, and, hopefully, agree to a real, sincere disarmament pact that would drastically decrease all forces, both nuclear and conventional. Furthermore, the MAD argument was criticized on the grounds that MAD only covered intentional, full-scale nuclear attacks by a rational, non-suicidal opponent with similar values. It did not take into account limited launches, accidental launches, rogue launches, or launches by non-state entities or covert proxies.

During the Reykjavik talks with Gorbachev in 1986, Ronald Reagan addressed Gorbachev's concerns about imbalance by stating that SDI would be given to the Soviet Union to prevent the imbalance from occurring. Gorbachev answered that he could not take this claim seriously.

Non-ICBM delivery

Another criticism of SDI was that it would not be effective against non-space faring weapons, namely cruise missile
Cruise missile
A cruise missile is a guided missile that carries an explosive payload and is propelled, usually by a jet engine, towards a land-based or sea-based target. Cruise missiles are designed to deliver a large warhead over long distances with high accuracy...

s, bomber
Bomber
A bomber is a military aircraft designed to attack ground and sea targets, by dropping bombs on them, or – in recent years – by launching cruise missiles at them.-Classifications of bombers:...

s, and non-conventional delivery methods. It was never intended to act as a defense against non-space faring weapons.

Soviet view of SDI

The Soviet response to the SDI during the period March 1983 through November 1985 provided indications of their view of the program both as a threat and as an opportunity to weaken NATO. The SDI was seen not only as a threat to the physical security of the Soviet Union but as part of an effort by the United States to seize the strategic initiative by neutralizing the military component of Soviet strategy. A major objective of that strategy was the political separation of Western Europe from the United States which
the Soviets sought to facilitate by aggravating allied concern over the SDI's potential implications for European security and economic interests. The Soviet predisposition to see deception behind the SDI was reinforced by their assessment of US intentions and capabilities and the utility of military deception in furthering the achievement of political goals.

Fiction and popular culture

Because of public awareness of the program and its controversial nature, SDI has been the subject of many fictional and pop culture references. This is not intended to be a complete list of those references.
  • In 1986, the British breakdance group The Willesden Dodgers
    The Willesden Dodgers
    The Willesden Dodgers was a British breakdance group during the 1980s with Pete Q. Harris, Nigel Green and Richard Jon Smith as the main members. They released numerous singles and provided soundtracks for films such as The Jewel of the Nile during 1985...

     released the track Not This President which was referring to President Reagan and the Strategic Defence Initiative.
  • The Japanese Heavy Metal
    Heavy metal music
    Heavy metal is a genre of rock music that developed in the late 1960s and early 1970s, largely in the Midlands of the United Kingdom and the United States...

     band Loudness
    Loudness (band)
    is a Japan-based heavy metal band formed in 1981 by guitarist Akira Takasaki and drummer Munetaka Higuchi. They were the first Japanese heavy metal act signed to a major label in the United States, releasing twenty-three studio albums...

    's song "S.D.I." is a criticism of the idea of this initiative inspiring nuclear war.
  • Dale Brown
    Dale Brown
    Dale Brown is an American author and aviator, most famous for his aviation techno-thriller novels, with thirteen New York Times best sellers to his name.Brown was born in Buffalo, New York...

    's novel Silver Tower details the adventures on and around a space station that employs an anti-ICBM laser system called Skybolt against a Soviet invasion of Iran; it would reappear in the 2007 novel Strike Force and the 2008 novel Shadow Command.
  • Tom Clancy
    Tom Clancy
    Thomas Leo "Tom" Clancy, Jr. is an American author, best known for his technically detailed espionage, military science, and techno thriller storylines set during and in the aftermath of the Cold War, along with video games on which he did not work, but which bear his name for licensing and...

    's novel The Cardinal of the Kremlin
    The Cardinal of the Kremlin
    The Cardinal of the Kremlin is a novel by Tom Clancy, featuring his character Jack Ryan. It is a sequel to The Hunt for Red October, based on the development of the Strategic Defense Initiative and its Soviet equivalent, covering themes including intelligence gathering and counterintelligence,...

    is based in part on a race between the USA and USSR to complete laser-based SDI systems.
  • Homer Hickam
    Homer Hickam
    Homer Hadley Hickam, Jr. is an American author, Vietnam veteran, and a former NASA engineer. His autobiographical novel Rocket Boys: A Memoir, was a #1 New York Times Best Seller, is studied in many American and international school systems, and was the basis for the popular film October Sky...

     Jr's novel Back to the Moon
    Back To The Moon
    Back to the Moon was Homer Hickam's first book-length fiction, published in June 1999. It is an adult, scientific thriller with insider information about NASA.- External links :*...

    used leftover SDI weapons, including the Homing Overlay Experiment, in an attempt to kill the crew of shuttle Columbia
    Space Shuttle Columbia
    Space Shuttle Columbia was the first spaceworthy Space Shuttle in NASA's orbital fleet. First launched on the STS-1 mission, the first of the Space Shuttle program, it completed 27 missions before being destroyed during re-entry on February 1, 2003 near the end of its 28th, STS-107. All seven crew...

    .
  • Whitley Streiber's novel Warday
    Warday
    Warday is a novel by Whitley Strieber and James Kunetka, first published in 1984. It is a fictionalized account of the authors traveling across America five years after a limited nuclear attack in order to assess how the nation had changed after the war. The novel takes the form of a research...

    details how the Soviet Union launches a preemptive, limited nuclear attack on the United States while it was deploying the Strategic Defense Initiative (called "Spiderweb" in the novel) out of fears that the SDI would make the USA potentially invulnerable to Soviet missile attacks.
  • In the Civilization series
    Civilization (computer game)
    Sid Meier's Civilization is a turn-based strategy "4X"-type strategy video game created by Sid Meier and Bruce Shelley for MicroProse in 1991. The game's objective is to "Build an empire to stand the test of time": it begins in 4000 BC and the players attempt to expand and develop their empires...

    , there are several references to ICBM defense systems similar to SDI.
  • The comedy movie Real Genius
    Real Genius
    Real Genius is a 1985 satirical comedy film directed by Martha Coolidge. The film's screenplay was written by Neal Israel, Pat Proft and Peter Torokvei. It stars Val Kilmer and Gabriel Jarret....

    follows college physics prodigies who are unknowingly induced to develop a space-based laser weapon system for the Air Force.
  • In RoboCop
    RoboCop
    RoboCop is a 1987 American science fiction-action film directed by Paul Verhoeven. Set in a crime-ridden Detroit, Michigan in the near future, RoboCop centers on a police officer who is brutally murdered and subsequently re-created as a super-human cyborg known as "RoboCop"...

    , a brief satirical news story mentions how a Strategic Defense platform codenamed Peace, malfunctioned in orbit, destroying a swathe of Southern California in the process.
  • Spies Like Us follows two duped 'spies' who are told to launch a single Soviet missile towards the USA as part of a black operation
    Black operation
    A black operation or black op is a covert operation typically involving activities that are highly clandestine and often outside of standard military protocol or even against the law.-Origins:...

     to demonstrate and justify the expense of SDI.
  • In the 1993 Larry Bond
    Larry Bond
    Larry Bond is an American writer and wargame designer. He is the designer of the Harpoon and Command at Sea gaming systems and several supplements for the games. His numerous novels include Dangerous Ground, Day of Wrath, The Enemy Within, Cauldron, Vortex and Red Phoenix...

     novel Cauldron
    Cauldron (novel)
    Cauldron is a novel by Larry Bond that centers on a European financial crisis that leads to a military confrontation between the United States and France. The instrument of French imperialism in this novel is a transnational organization known as the European Confederation . EurCon is dominated by...

    the GPALS system is depicted as having been deployed with the Brilliant Pebbles weapons included. They are used to destroy all French and German military satellites covering an invasion of Poland in the then-future of 1998.


See also

  • Ballistic Missile Defense Organization
    Ballistic Missile Defense Organization
    The Ballistic Missile Defense Organization was an agency of the United States Department of Defense that began on 20 May 1974 with the responsibility for all U.S. ballistic missile defense efforts. It evolved from the SAFEGUARD System Organization. The original mission of BMDO was comparable to...

     (BMDO)
  • National Missile Defense
    National Missile Defense
    National missile defense is a generic term for a type of missile defense intended to shield an entire country against incoming missiles, such as intercontinental ballistic missile or other ballistic missiles. Interception might be by anti-ballistic missiles or directed-energy weapons such as lasers...

     (NMD)
  • Ground-Based Midcourse Defense
    Ground-Based Midcourse Defense
    Ground-Based Midcourse Defense is the United States system for intercepting incoming warheads in space. Currently, it is a major component of the U.S. national missile defense strategy aimed against ballistic missiles, including intercontinental ballistic missiles...

     (GMD)
  • Missile Defense Agency
    Missile Defense Agency
    The Missile Defense Agency is the section of the United States government's Department of Defense responsible for developing a layered defense against ballistic missiles. The agency has its origins in the Strategic Defense Initiative, which was established in 1983 and was headed by Lt...

     (MDA)
  • National Aerospace Plane – partly funded by the SDIO
  • Anti-satellite weapon
    Anti-satellite weapon
    Anti-satellite weapons are designed to incapacitate or destroy satellites for strategic military purposes. Currently, only the United States, the former Soviet Union, and the People's Republic of China are known to have developed these weapons. On September 13, 1985, the United States destroyed US...

    s
  • Anti-ballistic missile
    Anti-ballistic missile
    An anti-ballistic missile is a missile designed to counter ballistic missiles .A ballistic missile is used to deliver nuclear, chemical, biological or conventional warheads in a ballistic flight trajectory. The term "anti-ballistic missile" describes any antimissile system designed to counter...

  • Militarization of space
    Militarisation of space
    The militarisation of space is the placement and development of weaponry and military technology in outer space.-History:Acquisition of high grounds for military advantage has been a perennial feature of military campaigns. For thousands of years, military tacticians have exploited the concept of...


External links

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