Though it was never fully developed or deployed, the research and technologies of SDI paved the way for some anti-ballistic missile systems of today. The Strategic Defense Initiative Organization (SDIO) was set up in 1984 within the United States Department of Defense to oversee the Strategic Defense Initiative. It gained the popular name Star Wars after the 1977 film by George Lucas. Under the administration of President Bill Clinton in 1993, its name was changed to the Ballistic Missile Defense Organization (BMDO) and its emphasis was shifted from national missile defense to theater missile defense; from global to regional coverage. BMDO was renamed to the Missile Defense Agency in 2002. This article covers defense efforts under the SDIO.
SDI is unique from the earlier U.S. and Soviet missile defense efforts. It envisioned using space-oriented basing of defensive systems as opposed to solely ground-launched interceptors. It also initially had the ambitious goal of providing a near total defense against a massive sophisticated ICBM attack, as opposed to previous systems, which were limited in defensive capacity and geographic coverage.
The initial focus of the strategic defense initiative was a nuclear explosion-powered X-ray laser designed at Lawrence Livermore National Laboratory by a scientist named Peter L. Hagelstein 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, a protégé and friend of Edward Teller, 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 speech on March 8, 1983, in Florida, ushered in the last phase of the Cold War, bringing the nuclear standoff with the Soviet Union to its most critical point before the collapse of the Soviet Union later that decade.
The concept for the space-based portion was to use lasers to shoot down incoming Soviet intercontinental ballistic missiles (ICBMs) armed with nuclear warheads. Nobel Prize-winning physicist Hans Bethe went to Livermore in February 1983 for a two-day 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.
In 1984, the Strategic Defense Initiative Organization (SDIO) was established to oversee the program, which was headed by Lt. General James Alan Abrahamson, USAF, a past Director of the NASA Space Shuttle program. 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 trace their roots back to this concept.
In his 1991 State of the Union Address George H. W. Bush 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 administration further shifted the focus to ground-based interceptor missiles and theater scale systems, forming the Ballistic Missile Defense Organization (BMDO) and closing the SDIO. Ballistic missile defense has been revived by the George W. Bush administration as the National Missile Defense (since renamed "Ground-Based Midcourse Defense").
FLAGE scored a direct hit against a MGM-52 Lance missile in flight, at White Sands Missile 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 (PAC-3) missile.
The Homing Overlay Experiment (HOE) was the first system tested by the Army that employed hit-to-kill; four test launches were conducted in 1983 and 1984. The first three tests failed due to guidance and sensor problems. 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.
The HOE technology was later used by the SDIO and expanded into the Exoatmospheric Reentry-vehicle Interception System (ERIS) program.
An early focus of the project was toward a curtain of X-ray lasers powered by nuclear explosions. 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 in order to produce an impenetrable barrier to incoming warheads. 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 and Aerogel, the Electron-Beam Ion Trap facility for physics research, and enhanced techniques for early detection of breast cancer.
Beginning in 1985, the Air Force tested an SDIO-funded deuterium fluoride laser known as Mid-Infrared Advanced Chemical Laser (MIRACL) at White Sands Missile Range. During a simulation, the laser successfully destroyed a Titan missile booster in 1985 and it was successfully tested on target drones simulating cruise missiles for the US Navy. After the SDIO closed, the MIRACL was tested on an old Air Force satellite for potential use as an Anti-satellite weapon, with mixed results. The technology was also used to develop the Tactical High Energy Laser, (THEL) which is being tested to shoot down artillery shells.
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 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 (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, a technique now used in civilian telescopes to remove atmospheric distortions.
A hypervelocity rail gun works very much like a particle accelerator insofar as it converts electrical potential energy into kinetic energy imparted to the projectile. A conductive pellet (the projectile) is attracted down the rails by electric current 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 amperage and voltage. 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 gs. In order to be effective, the fired projectile must first survive the mechanical stress of firing, 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).
Brilliant Pebbles was a non-nuclear system of satellite-based, watermelon-sized mini-missiles designed to use a high-velocity 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”. 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 and SDI technologies may also have a role in future missile defense efforts.
SDIO sensor research encompassed visible light, ultraviolet, infrared, and radar 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.
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).
In war-fighting, countermeasures can have a variety of meanings:
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 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 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 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.
SDI may have been first dubbed "Star Wars" by opponent Dr. Carol Rosin, a consultant and former spokesperson for Wernher von Braun. However, Missile Defense Agency 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 describing the proposal as "reckless Star Wars schemes. Some critics used that term derisively, implying it was an impractical science fiction fantasy, but supporters have adopted the usage as well on the grounds that yesterday's science fiction is often tomorrow's engineering. 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 and asserted that the nickname gave an entirely wrong impression of SDI.
Ashton Carter, 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, who worked with Edward Teller on both the nuclear bomb and the hydrogen bomb at Los Alamos, 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, 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 that concluded "the X-ray laser offers no prospect of being a useful component in a system for ballistic missile defense."
Teller countered that Bethe and the other anti-defense activists could not have it both ways. Bethe, who had helped him usher in the nuclear age, had become opposed to nuclear weapons and afraid of nuclear war. At the same time, Bethe was also opposed to stopping the threat of offensive capabilities through massive defensive programs. Teller testified before Congress that "instead of [Berthe] 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 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.
Supporters of SDI hail it for contributing to or at least accelerating the fall of the Soviet Union by the strategy of technology, which was a prevalent doctrine at the time. At Reagan and Gorbachev's October 1986 meeting in Iceland, Gorbachev opposed this defensive shield, while Reagan wanted to keep it, and offered to give the technology to the Soviets. Gorbachev said he didn't believe the offer, saying "Excuse me, Mr. President, but I do not take your idea of sharing SDI seriously. You don't want to share even petroleum equipment, automatic machine tools or equipment for dairies, while sharing SDI would be a second American Revolution." Both Reagan and Gorbachev proposed total elimination of all nuclear-armed missiles, but SDI and intermediate-range missiles were sticking points. While SDI was a disagreement, the summit led to the Intermediate-Range Nuclear Forces Treaty, which some have claimed was an outgrowth of Gorbachev's fear of SDI. Opponents of the program say that Mikhail Gorbachev's reforms were the cause of the USSR's collapse and that SDI was an unrealistic and expensive program. Furthermore, some believed that Gorbachev's opposition to SDI was intended to encourage the United States to pursue ABM defense at great economic expense. To quote Gorbachev, "But I think that I am even helping the president [Reagan] with SDI. After all, your people say that if Gorbachev attacks SDI and space weapons so much, it means the idea deserves more respect. They even say that if it were not for me, no one would listen to the idea at all. And some even claim that I want to drag the United States into unnecessary expenditures with this."
Ronald Reagan responded that SDI would be given to the Soviet Union to prevent the imbalance from occurring. How and whether this massive technology transfer would have happened was often debated. A complication of the MAD argument was that MAD only covered intentional nuclear attacks by a rational opponent with similar values, not accidental launches, rogue launches, or launches by non-state entities.