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Project Excalibur was a
Lawrence Livermore National Laboratory Lawrence Livermore National Laboratory (LLNL) is a federal research facility in Livermore, California, United States. The lab was originally established as the University of California Radiation Laboratory, Livermore Branch in 1952 in response ...
(LLNL)
Cold War The Cold War is a term commonly used to refer to a period of geopolitical tension between the United States and the Soviet Union and their respective allies, the Western Bloc and the Eastern Bloc. The term '' cold war'' is used because the ...
era research program to develop an
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 tens of nanometers (nm) wavelength ...
system as a
ballistic missile defense Missile defense is a system, weapon, or technology involved in the detection, tracking, interception, and also the destruction of attacking missiles. Conceived as a defense against nuclear-armed intercontinental ballistic missiles (ICBMs), ...
(BMD) for the
United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...
. The concept involved packing large numbers of expendable lasers around a
nuclear device A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission (fission bomb) or a combination of fission and fusion reactions ( thermonuclear bomb), producing a nuclear explosion. Both bomb ...
, which would orbit in space. During an attack, the device would be detonated, with the X-rays released focused by each laser to destroy multiple incoming target missiles. Because the system would be deployed above the Earth's atmosphere, the X-rays could reach missiles thousands of kilometers away, providing protection over a wide area.
Anti-ballistic missile An anti-ballistic missile (ABM) is a surface-to-air missile designed to counter ballistic missiles (missile defense). Ballistic missiles are used to deliver nuclear weapon, nuclear, Chemical weapon, chemical, Bioagent, biological, or conventiona ...
(ABM) systems of the time only attacked the enemy
nuclear warheads A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either nuclear fission, fission (fission bomb) or a combination of fission and nuclear fusion, fusion reactions (Thermonuclear weapon, thermonu ...
after they were released by
ICBM An intercontinental ballistic missile (ICBM) is a ballistic missile with a range greater than , primarily designed for nuclear weapons delivery (delivering one or more thermonuclear warheads). Conventional, chemical, and biological weapons c ...
s. As a single ICBM could carry as many as a dozen warheads, dozens of defense missiles were required per attacking missile. A single Excalibur device contained up to fifty lasers and could potentially destroy a corresponding number of missiles, with all of the warheads still onboard. A single Excalibur could thus destroy dozens of ICBMs and hundreds of warheads for the cost of a single nuclear bomb, dramatically reversing the
cost-exchange ratio In anti-ballistic missile (ABM) defence the cost-exchange ratio is the ratio of the incremental cost to the aggressor of getting one additional warhead through the defence screen, divided by the incremental cost to the defender of offsetting the ad ...
that had previously doomed ABM systems. The basic concept behind Excalibur was conceived in the 1970s by George Chapline Jr. and further developed by Peter L. Hagelstein, both part of
Edward Teller Edward Teller ( hu, Teller Ede; January 15, 1908 – September 9, 2003) was a Hungarian-American theoretical physicist who is known colloquially as "the father of the hydrogen bomb" (see the Teller–Ulam design), although he did not care fo ...
's "O-Group" in LLNL. After a successful test in 1980, in 1981 Teller and
Lowell Wood Lowell Lincoln Wood Jr. (born 1941) 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 In ...
began talks with US president
Ronald Reagan Ronald Wilson Reagan ( ; February 6, 1911June 5, 2004) was an American politician, actor, and union leader who served as the 40th president of the United States from 1981 to 1989. He also served as the 33rd governor of California from 1967 ...
about the concept. These talks, combined with strong support from lobbyists at the
Heritage Foundation The Heritage Foundation (abbreviated to Heritage) is an American conservative think tank based in Washington, D.C. that is primarily geared toward public policy. The foundation took a leading role in the conservative movement during the presiden ...
, helped Reagan ultimately to announce the
Strategic Defense Initiative The Strategic Defense Initiative (SDI), derisively nicknamed the "''Star Wars'' program", was a proposed missile defense system intended to protect the United States from attack by ballistic strategic nuclear weapons (intercontinental ballistic ...
(SDI) in 1983. Further
underground nuclear test Underground nuclear testing is the Nuclear weapons testing, test detonation of nuclear weapons that is performed underground. When the device being tested is buried at sufficient depth, the nuclear explosion may be contained, with no release of ...
s through the early 1980s suggested progress was being made, and this influenced the 1986
Reykjavík Summit The Reykjavík Summit was a summit meeting between U.S. President Ronald Reagan and General Secretary of the Communist Party of the Soviet Union Mikhail Gorbachev, held in Reykjavík, Iceland, on 11–12 October 1986. The talks collapsed at the l ...
, where Reagan refused to give up the possibility of proof-testing SDI technology with nuclear testing in space. Researchers at Livermore and Los Alamos began to raise concerns about the test results. Teller and Wood continued to state the program was proceeding well, even after a critical test in 1985 demonstrated it was not working as expected. This led to significant criticism within the US weapons laboratories. In 1987, the infighting became public, leading to an investigation on whether LLNL had misled the government about the Excalibur concept. In a ''
60 Minutes ''60 Minutes'' is an American television news magazine broadcast on the CBS television network. Debuting in 1968, the program was created by Don Hewitt and Bill Leonard, who chose to set it apart from other news programs by using a unique styl ...
'' interview in 1988, Teller attempted to walk out rather than answer questions about the lab's treatment of a fellow worker who questioned the results. Further tests revealed additional problems, and in 1988 the budget was cut dramatically. The project officially continued until 1992 when its last planned test, ''Greenwater'' of Operation Julin, was cancelled.


History


Conceptual development

The conceptual basis of short-wavelength lasers, using X-rays and
gamma ray A gamma ray, also known as gamma radiation (symbol γ or \gamma), is a penetrating form of electromagnetic radiation arising from the radioactive decay of atomic nuclei. It consists of the shortest wavelength electromagnetic waves, typically ...
s, is the same as that of their visible-light counterparts. There were discussions of such devices as early as 1960, the year the first ruby laser was demonstrated. The first announcement of a successful X-ray laser was made in 1972 by the
University of Utah The University of Utah (U of U, UofU, or simply The U) is a public research university in Salt Lake City, Utah. It is the flagship institution of the Utah System of Higher Education. The university was established in 1850 as the University of De ...
. Researchers spread thin layers of copper atoms on
microscope slide A microscope slide is a thin flat piece of glass, typically 75 by 26 mm (3 by 1 inches) and about 1 mm thick, used to hold objects for examination under a microscope. Typically the object is mounted (secured) on the slide, and then b ...
s and then heated them with pulses from a neodymium glass laser. This caused spots to appear on X-ray film in the direction of the layers and none in other directions. The announcement caused great excitement, but it was soon overshadowed by the fact that no other labs could reproduce the results, and the announcement was soon forgotten. In 1974, the
University of Paris-Sud Paris-Sud University (French: ''Université Paris-Sud''), also known as University of Paris — XI (or as Université d'Orsay before 1971), was a French research university distributed among several campuses in the southern suburbs of Paris, in ...
announced lasing in an
aluminum Aluminium (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. It has ...
plasma created by a pulse of laser light, but, once again, the results were regarded skeptically by other labs.
DARPA The Defense Advanced Research Projects Agency (DARPA) is a research and development agency of the United States Department of Defense responsible for the development of emerging technologies for use by the military. Originally known as the Adv ...
had been funding low-level research into high-frequency lasers since the 1960s. By late 1976 they had all but given up on them. They commissioned a report by Physical Dynamics, which outlined possible uses of such a laser, including space-based weapons. None of these seemed promising, and DARPA dropped funding for X-ray laser research in favor of the more promising
free electron laser A free-electron laser (FEL) is a (fourth generation) light source producing extremely brilliant and short pulses of radiation. An FEL functions and behaves in many ways like a laser, but instead of using stimulated emission from atomic or molecula ...
. In June 1977, two well-known Soviet researchers, Igor Sobel'man, and Vladilen Letokhov, displayed a film exposed to the output of plasmas of
chlorine Chlorine is a chemical element with the Symbol (chemistry), symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate betwee ...
,
calcium Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to ...
and
titanium Titanium is a chemical element with the symbol Ti and atomic number 22. Found in nature only as an oxide, it can be reduced to produce a lustrous transition metal with a silver color, low density, and high strength, resistant to corrosion in ...
, similar to the Utah results. They were careful to point out that the results were very preliminary and further study was required. Over the next few years, a small number of additional papers on the topic were presented. The most direct of these was Sobel'man's statements at a 1979 conference in
Novosibirsk Novosibirsk (, also ; rus, Новосиби́рск, p=nəvəsʲɪˈbʲirsk, a=ru-Новосибирск.ogg) is the largest city and administrative centre of Novosibirsk Oblast and Siberian Federal District in Russia. As of the Russian Census ...
when he said he was observing lasing in a calcium plasma. As with earlier announcements, these results were met with skepticism.


First attempts at Livermore

George Chapline had been studying the X-ray laser concept through the 1970s. Chapline was a member of Teller's speculative-project "O-Group" and began to discuss the concept with fellow O-Group member Lowell Wood, Teller's protégé. The two collaborated on a major review of the X-ray laser field in 1975. They suggested such a device would be a powerful tool in materials science, for making
hologram Holography is a technique that enables a wavefront to be recorded and later re-constructed. Holography is best known as a method of generating real three-dimensional images, but it also has a wide range of other Holography#Applications, applic ...
s of
virus A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Since Dmitri Ivanovsky's 1 ...
es where a conventional laser's longer wavelength did not provide the required
optical resolution Optical resolution describes the ability of an imaging system to resolve detail, in the object that is being imaged. An imaging system may have many individual components, including one or more lenses, and/or recording and display components. ...
, and as a sort of flashbulb for taking images of the
nuclear fusion Nuclear fusion is a reaction in which two or more atomic nuclei are combined to form one or more different atomic nuclei and subatomic particles ( neutrons or protons). The difference in mass between the reactants and products is manifest ...
process in their
inertial confinement fusion Inertial confinement fusion (ICF) is a fusion energy process that initiates nuclear fusion reactions by compressing and heating targets filled with thermonuclear fuel. In modern machines, the targets are small spherical pellets about the size of ...
devices. This review contained the calculations that demonstrated both the rapid reaction times needed in such a device and the extremely high energies required for pumping. Chapline attended a meeting where Sobel'man's work on X-ray lasers was presented. He had learned of the unique
underground nuclear test Underground nuclear testing is the Nuclear weapons testing, test detonation of nuclear weapons that is performed underground. When the device being tested is buried at sufficient depth, the nuclear explosion may be contained, with no release of ...
s made on behalf of the Defense Nuclear Agency (DNA), where the burst of X-rays produced by the nuclear reactions were allowed to travel down a long tunnel while the blast itself was cut off by large doors that slammed shut as the explosion approached. These tests were used to investigate the effects of X-rays from exoatmospheric nuclear explosions on
reentry vehicle Atmospheric entry is the movement of an object from outer space into and through the gases of an atmosphere of a planet, dwarf planet, or natural satellite. There are two main types of atmospheric entry: ''uncontrolled entry'', such as the entr ...
s. He realized this was a perfect way to pump an X-ray laser. After a few weeks of work, he came up with a testable concept. At this time the DNA was making plans for another of its X-ray effects tests, and Chapline's device could easily be tested in the same "shot". The test shot, ''Diablo Hawk'', was carried out on 13 September 1978 as part of the
Operation Cresset The United States's Cresset nuclear test series was a group of 22 nuclear test Nuclear weapons tests are experiments carried out to determine nuclear weapons' effectiveness, Nuclear weapon yield, yield, and explosive capability. Testing nu ...
series. However, the instrumentation on Chapline's device failed, and there was no way to know if the system had worked. Congress directed that $10million be given to both
Lawrence Livermore National Laboratory Lawrence Livermore National Laboratory (LLNL) is a federal research facility in Livermore, California, United States. The lab was originally established as the University of California Radiation Laboratory, Livermore Branch in 1952 in response ...
(LLNL) and
Los Alamos National Laboratory Los Alamos National Laboratory (often shortened as Los Alamos and LANL) is one of the sixteen research and development laboratories of the United States Department of Energy (DOE), located a short distance northwest of Santa Fe, New Mexico, ...
(LANL) for weapons tests on entirely new concepts. Chapline was given the go-ahead to plan for a new test dedicated to the X-ray laser concept. In the DNA tests, the reentry vehicle had to be retrieved for study after the test, which demanded the complex system of protective doors and other techniques that made these tests very expensive. For the X-ray laser test, all of this could be ignored, as the laser was designed to be destroyed in the explosion. This allowed the laser to be placed at the top of the vertical access shaft, which greatly lowered the cost of the test from the typical $40million needed in a DNA shot. Given the schedule at the
Nevada Test Site The Nevada National Security Site (N2S2 or NNSS), known as the Nevada Test Site (NTS) until 2010, is a United States Department of Energy (DOE) reservation located in southeastern Nye County, Nevada, about 65 miles (105 km) northwest of th ...
, their test would have to wait until 1980.


Dauphin success

Peter Hagelstein Peter L. Hagelstein is an associate professor of electrical engineering at the Massachusetts Institute of Technology (MIT), affiliated with the Research Laboratory of Electronics (RLE). Hagelstein received a B.S. and M.S. in 1976 and Ph.D. in ele ...
was in an undergraduate physics program at
MIT The Massachusetts Institute of Technology (MIT) is a private land-grant research university in Cambridge, Massachusetts. Established in 1861, MIT has played a key role in the development of modern technology and science, and is one of the m ...
in 1974 when he applied for a
Hertz Foundation The Fannie and John Hertz Foundation is an American non-profit organization that awards fellowships to Ph.D. students in the applied physical, biological and engineering sciences. The fellowship provides $250,000 of support over five years. The ...
scholarship. Teller was on the Hertz board, and Hagelstein soon had an interview with Lowell Wood. Hagelstein won the scholarship, and Wood then went on to offer him a summer position at LLNL. He had never heard of the lab, and Wood explained they were working on lasers, fusion, and similar concepts. Hagelstein arrived in May 1975, but nearly left when he found the area to be "disgusting" and immediately surmised they were working on weapons research when he saw the barbed wire and armed guards. He stayed on only because he met interesting people. Hagelstein was given the task of simulating the X-ray laser process on LLNL's
supercomputer A supercomputer is a computer with a high level of performance as compared to a general-purpose computer. The performance of a supercomputer is commonly measured in floating-point operations per second ( FLOPS) instead of million instructions ...
s. His program, known as XRASER for "X-Ray laser", eventually grew to about 40,000 lines of code. He received his master's degree in 1976 and took a full-time job at the lab, intending to lead the development of a working laser. The idea was to use the lab's powerful fusion lasers as an energy source, as Hagelstein and Wood had suggested in their review paper. Hagelstein used XRASER to simulate about 45 such concepts before he found one that appeared to work. These used the lasers to heat metal foils and give off X-rays, but by the late 1970s, none of these experiments had been successful. After the Diablo Hawk failure, Hagelstein reviewed Chapline's idea and came up with a new concept that should be much more efficient. Chapline had used a lightweight material, a fiber taken from a local weed, but Hagelstein suggested using a metal rod instead. Although initially skeptical, Wood came to support the idea and successfully argued that both concepts be tested in Chapline's shot. The critical test was carried out on 14 November 1980 as ''Dauphin'', part of
Operation Guardian Operation Guardian was a series of 14 nuclear tests conducted by the United States in 1980–1981 at the Nevada Test Site. These tests followed the ''Operation Tinderbox'' series and preceded the ''Operation Praetorian'' series. Referenc ...
. Both lasers worked, but Hagelstein's design was much more powerful. The lab soon decided to move forward with Hagelstein's version, forming the "R Program", led by another O-Group member, Tom Weaver.


Renewed interest

Hagelstein published his PhD thesis in January 1981 on the "Physics of Short-wavelength-laser Design". In contrast to Chapline and Wood's earlier work which focused on civilian applications, the thesis' introduction mentions several potential uses, even weapons taken from science fiction works. Hagelstein soon returned to the civilian side of the X-ray laser development, initially developing a concept in which the lab's fusion lasers would produce a plasma whose photons would pump another material. This was initially based on fluorine gas confined inside a chromium foil film. This proved to be too difficult to manufacture, so a system more like the earlier Soviet concepts was developed. The laser would deposit enough energy in a selenium wire to cause 24 of the electrons to be ionized, leaving behind 10 electrons that would be pumped by collisions with the free electrons in the plasma. After several attempts using the
Novette laser Novette was a two beam neodymium glass (phosphate glass) testbed laser built at Lawrence Livermore National Laboratory in about 15 months throughout 1981 and 1982 and was completed in January 1983. Novette was made using recycled parts from the dis ...
as an energy source, on 13 July 1984 the system worked for the first time. The team calculated that the system produced laser amplification of about 700, which they considered to be strong evidence of lasing. Dennis Matthews presented the success at the October 1984 American Physical Society Plasma Physics Meeting in Boston, where
Szymon Suckewer Szymon Suckewer (born April 10, 1938 in Warsaw) is a Polish-born American physicist, and professor emeritus at Princeton University. His primary fields of interest include X-ray lasers, and X-ray microscopy, particularly the generation of ultrashort ...
of
Princeton University Princeton University is a private university, private research university in Princeton, New Jersey. Founded in 1746 in Elizabeth, New Jersey, Elizabeth as the College of New Jersey, Princeton is the List of Colonial Colleges, fourth-oldest ins ...
presented their evidence of lasing in carbon using a much smaller laser and confined the plasma using magnets.


Teller in Washington, ''AvWeek'' "leaks"

The success of the Dauphin test presented a potential new solution to the BMD problem. The X-ray laser offered the possibility that many laser beams could be generated from a single nuclear weapon in orbit, meaning a single weapon would destroy many ICBMs. This would so blunt the attack that any US response would be overwhelming in comparison. Even if the Soviets launched a full-scale attack, it would limit US casualties to 30million. In February 1981, Teller and Wood traveled to Washington to present the technology to the policy makers and request greater financial support to pursue the development. This presented a problem. As fellow LLNL physicist Hugh DeWitt put it, "It has long been known that Teller and Wood are extreme technological optimists and super salesmen for hypothetical new weapons systems," or as Robert Park puts it, "Anyone who knows Teller's record recognizes that he is invariably optimistic about even the most improbable technological schemes." Although this salesmanship had little effect in US military circles, it proved to be a continual annoyance in Congress, having a negative effect on the lab's credibility when these concepts failed to pan out. To avoid this, Roy Woodruff, the associate director of the weapons section, went with them to ensure the two did not oversell the concept. In meetings with various congressional groups, Teller and Wood explained the technology but refused to give dates on when it might be available. Only days later, the 23 February 1981 edition of ''
Aviation Week and Space Technology ''Aviation Week & Space Technology'', often abbreviated ''Aviation Week'' or ''AW&ST'', is the flagship magazine of the Aviation Week Network. The weekly magazine is available in print and online, reporting on the aerospace, defense and aviati ...
'' carried an article on the ongoing work. It described the Dauphin shot in some detail, going on to mention the earlier 1978 test, but incorrectly ascribing that to a
krypton fluoride laser A krypton fluoride laser (KrF laser) is a particular type of excimer laser, which is sometimes (more correctly) called an exciplex laser. With its 248 nanometer wavelength, it is a deep ultraviolet laser which is commonly used in the production of ...
(KrF). It went on to describe the battle-station concept in which a single bomb would be surrounded by laser rods that could destroy as many as fifty missiles, and stated that "X-Ray lasers based on the successful Dauphin test 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." This was the first in a series of such articles in this and other sources based on a "steady leak of top secret information".


High Frontier

By this time, LLNL was not the only group lobbying the government about space-based weapons. In 1979,
Daniel O. Graham Daniel Orrin Graham (April 13, 1925 – December 31, 1995) was a United States Army officer who ultimately rose to the rank of lieutenant general (United States), lieutenant general. Graham served in Germany, Korea, and Vietnam and received sever ...
had been asked by
Ronald Reagan Ronald Wilson Reagan ( ; February 6, 1911June 5, 2004) was an American politician, actor, and union leader who served as the 40th president of the United States from 1981 to 1989. He also served as the 33rd governor of California from 1967 ...
to begin exploring the idea of missile defense, and in the years since had become a strong advocate of what was earlier known as Project BAMBI (Ballistic Missile Boost Intercept), but now updated as " Smart Rocks". This required dozens of large satellites carrying many small, relatively simple missiles which would be launched at the ICBMs and track them like a conventional
heat seeking missile Infrared homing is a passive weapon guidance system which uses the infrared (IR) light emission from a target to track and follow it seamlessly. Missiles which use infrared seeking are often referred to as "heat-seekers" since infrared is rad ...
. That same year,
Malcolm Wallop Malcolm Wallop (February 27, 1933 – September 14, 2011) was an American rancher and politician. He served as a United States Senator from Wyoming from 1977 to 1995. He was a member of the Republican Party. Early years Wallop was born in New Yo ...
and his aide
Angelo Codevilla Angelo Maria Codevilla (May 25, 1943 – September 20, 2021) was an Italian-American professor of international relations at what is now the Pardee School of Global Studies at Boston University. He served as a U.S. Navy officer, a foreign servi ...
wrote an article on "Opportunities and Imperatives in Ballistic Missile Defense", which was to be published later that year in Strategic Review. They were later joined by Harrison Schmidt and Teller in forming what became known as the "laser lobby", advocating the building of laser-based BMD systems. Their concept, known simply as the Space Based Laser, used large
chemical laser A chemical laser is a laser that obtains its energy from a chemical reaction. Chemical lasers can reach continuous wave output with power reaching to megawatt levels. They are used in industry for cutting and drilling. Common examples of chemical ...
s placed in orbit. Graham was able to garner interest from other Republican supporters, and formed a group who would help advocate for his concept. The group was chaired by
Karl Bendetsen Colonel Karl Robin Bendetsen (October 11, 1907 – June 28, 1989) was an American politician and military officer who served in the Washington Army National Guard during World War II and later as the United States Under Secretary of the Army. Be ...
and was provided space at the
Heritage Foundation The Heritage Foundation (abbreviated to Heritage) is an American conservative think tank based in Washington, D.C. that is primarily geared toward public policy. The foundation took a leading role in the conservative movement during the presiden ...
. The group invited the laser lobby to join them to plan a strategy to introduce these concepts to the incoming president. At one of the Heritage meetings, Graham said there was a serious problem for the Excalibur concept. He noted that if the Soviets launched a missile at the satellite, the US had only two choicesthey could allow the missile to hit Excalibur and destroy it, or it could defend itself by shooting down the missile, which would also destroy Excalibur. In either case, a single missile would destroy the station, which invalidated the entire concept of the system in terms of having a single weapon that would destroy a large portion of the Soviet fleet. At the time, Teller was stumped. At the next meeting, he and Wood had an answer, apparently Teller's own concept; instead of being based on satellites, Excalibur would be placed in submarines and "pop-up" when the Soviets launched their missiles. This would also bypass another serious concern, that nuclear weapons in space were outlawed and it was unlikely the government or public would allow these. The group first met with the president on 8January 1982. Planned to last 15 minutes, the meeting went on for an hour. Present were Teller, Bendetsen, William Wilson and
Joseph Coors Joseph Coors, Sr. (November 12, 1917 – March 15, 2003), was the grandson of brewer Adolph Coors and president of Coors Brewing Company. Birth and education Coors was born in 1917 to Alice May Kistler (1885–1970) and Adolph Coors II. His sibl ...
of the "
Kitchen Cabinet Kitchen cabinets are the built-in furniture installed in many kitchens for storage of food, cooking equipment, and often Silver (household), silverware and Dishware, dishes for table service. Home appliance, Appliances such as refrigerators, dish ...
". Graham and Wallop were not represented and the group apparently dismissed their concepts. The same group met with the president another three times. Meanwhile, Teller continued to attack Graham's interceptor-based concept, as did other members of the group. There had been extensive studies on BAMBI in the 1960s and every few years since. These invariably reported the concept was simply too grandiose to work. Graham, seeing the others outmaneuver him after the first meetings, left the group and formed "High Frontier Inc.", publishing a glossy book on the topic in March 1982. Before publication, he had sent a copy to the
US Air Force The United States Air Force (USAF) is the air service branch of the United States Armed Forces, and is one of the eight uniformed services of the United States. Originally created on 1 August 1907, as a part of the United States Army Signal ...
for comment. They responded with another report stating the concept "had no technical merit and should be rejected". In spite of this review, the High Frontier book was widely distributed and quickly found followers. This led to a curious situation in early 1982, later known as the "laser wars", with the House supporting Teller and the Senate supporting Wallop's group. Later that summer, Teller complained to
William F. Buckley William Frank Buckley Jr. (born William Francis Buckley; November 24, 1925 – February 27, 2008) was an American public intellectual, conservative author and political commentator. In 1955, he founded ''National Review'', the magazine that stim ...
on '' Firing Line'' that he did not have access to the president. This led to a 4September meeting with the president without the rest of the High Frontier group. Teller said recent advances in Soviet weapons would soon put them in a position to threaten the US and they needed to build Excalibur without delay. Without Woodruff to temper his comments, Teller told the president the system would be ready for deployment in five years and that it was time to talk about "assured survival" instead of "assured destruction". ''Aviation Week'' reported that Teller had asked for $200million a year "over the next several years" to develop it.


Early skepticism

George A. Keyworth, II had been appointed to the position as Reagan's science advisor at the suggestion of Teller. He was present at the first meeting with the Heritage group, and a few days later at a White House staff meeting he was quoted expressing his concerns that the concepts had "very difficult technical aspects". Shortly thereafter,
Edwin Meese Edwin Meese III (born December 2, 1931) is an American attorney, law professor, author and member of the Republican Party who served in official capacities within the Ronald Reagan's gubernatorial administration (1967–1974), the Reagan pre ...
suggested Keyworth form an independent group to study the feasibility of such a system. The work was passed to Victor H. Reis, formerly of the
Lincoln Laboratory The MIT Lincoln Laboratory, located in Lexington, Massachusetts, is a United States Department of Defense federally funded research and development center chartered to apply advanced technology to problems of national security. Research and dev ...
and now the assistant director of the
Office of Science and Technology Policy An office is a space where an organization's employees perform administrative work in order to support and realize objects and goals of the organization. The word "office" may also denote a position within an organization with specific dut ...
. He formed a panel including Charles Townes, Nobel winner as the co-inventor of the
maser A maser (, an acronym for microwave amplification by stimulated emission of radiation) is a device that produces coherent electromagnetic waves through amplification by stimulated emission. The first maser was built by Charles H. Townes, Ja ...
and laser,
Harold Agnew Harold Melvin Agnew (March 28, 1921 – September 29, 2013) was an American physicist, best known for having flown as a scientific observer on the Hiroshima bombing mission and, later, as the third director of the Los Alamos National Laboratory ...
, former director of LANL, and chaired by
Edward Frieman Edward Allan Frieman (January 19, 1926 – April 11, 2013) was an American physicist who worked on plasma physics and nuclear fusion. He was the director of the Scripps Institution of Oceanography from 1986 through 1996, and then the senior vice ...
, vice president of military science contractor
Science Applications International Corporation Science Applications International Corporation (SAIC), Inc. is an American technology company headquartered in Reston, Virginia that provides government services and information technology support. History The original SAIC was created in 196 ...
(SAIC). Keyworth gave them a year to study the issues, and did not interfere with their process. The formation of this panel apparently worried Teller, who suspected they would not agree with his assessments of Excalibur's viability. In response, he stepped up his fundraising efforts, spending a considerable time in 1982 in Washington lobbying for a
Manhattan Project The Manhattan Project was a research and development undertaking during World War II that produced the first nuclear weapons. It was led by the United States with the support of the United Kingdom and Canada. From 1942 to 1946, the project w ...
-level effort to bring the system to production as soon as possible. While he was not part of the Frieman panel, he was part of the White House Science Council, and appeared at their meetings to continue pressuring for further development. In June 1982, the Frieman panel asked LLNL to review their own progress. Led by Woodruff, the lab returned a fairly conservative review. They suggested that if they were provided $150–$200million a year over six years they could decide whether the concept was feasible. They said a weapon could not possibly be ready before the mid-1990s, at the very earliest. In its final report, the panel concluded that the system simply could not be thought of as a military technology. Teller was apoplectic, and threatened to resign from the Science Council. He ultimately agreed to a second review by LLNL. This review was even more critical of the concept, stating that, due to energy limits, the system would be useful only against missiles at short range and that would limit it to those missiles launched from locations close to the United States, like
submarine-launched ballistic missile A submarine-launched ballistic missile (SLBM) is a ballistic missile capable of being launched from submarines. Modern variants usually deliver multiple independently targetable reentry vehicles (MIRVs), each of which carries a nuclear warhead ...
s. In the meantime, while Keyworth continued to support the concepts publicly, he was careful not to make statements that sounded like outright support. He spoke of the promise of the systems and their potential. But when asked about Excalibur after receiving the Frieman report, he was much more blunt and told reporters the concept was probably unusable. In 1985, he quit the position and returned to private industry. Teller's continual presence in Washington soon came to the attention of his former friend,
Hans Bethe Hans Albrecht Bethe (; July 2, 1906 – March 6, 2005) was a German-American theoretical physicist who made major contributions to nuclear physics, astrophysics, quantum electrodynamics, and solid-state physics, and who won the 1967 Nobel ...
. Bethe had worked with Teller on the
H-bomb A thermonuclear weapon, fusion weapon or hydrogen bomb (H bomb) is a second-generation nuclear weapon design. Its greater sophistication affords it vastly greater destructive power than first-generation nuclear bombs, a more compact size, a lowe ...
but had since gone on to become a major critic of the bomb industry, and especially ABM systems. He wrote several seminal articles in the 1960s highly critical of the
US Army The United States Army (USA) is the land service branch of the United States Armed Forces. It is one of the eight U.S. uniformed services, and is designated as the Army of the United States in the U.S. Constitution.Article II, section 2, cla ...
's efforts to build an ABM system, demonstrating that any such system was relatively inexpensive to defeat and would simply prompt the Soviets to build more ICBMs. Bethe remained an opponent of ABM systems, and when he heard of the Excalibur effort he arranged a trip to LLNL to grill them on the concept. In a two-day series of meetings in February 1983, Hagelstein managed to convince Bethe the physics was sound. Bethe remained convinced the idea was unlikely to be able to stop a Soviet attack, especially if they designed their systems knowing such a system existed. He soon co-authored a report by the
Union of Concerned Scientists The Union of Concerned Scientists (UCS) is a nonprofit science advocacy organization based in the United States. The UCS membership includes many private citizens in addition to professional scientists. Anne Kapuscinski, Professor of Environmenta ...
outlining objections to the concept, the simplest being that the Soviets could simply overwhelm it.


SDI

Reagan had long been deeply critical of current nuclear doctrine, which he and his aides derided as a "mutual suicide pact". He was extremely interested in the Heritage group's proposals. While he made no overt moves at the time, he spent a significant amount of time in 1982 gathering information from various sources on whether or not the system was possible. Reports by both the
Department of Defense Department of Defence or Department of Defense may refer to: Current departments of defence * Department of Defence (Australia) * Department of National Defence (Canada) * Department of Defence (Ireland) * Department of National Defense (Philipp ...
and the White House's own Science Council would feed into this process. In early 1983, before many of these reports had been returned, Reagan decided to announce what would become SDI. Few people were told of this decision and even Keyworth learned of it only a few weeks before it was going to be announced. When he showed a draft of the speech to Reis, Reis said it was "
Laetrile Amygdalin (from Ancient Greek: ' "almond") is a naturally occurring chemical compound found in many plants, most notably in the seeds (kernels) of apricots, bitter almonds, apples, peaches, cherries, and plums. Amygdalin is classified as a ...
", referring to the
quack cure Quackery, often synonymous with health fraud, is the promotion of fraudulent or ignorant medical practices. A quack is a "fraudulent or ignorant pretender to medical skill" or "a person who pretends, professionally or publicly, to have skill, ...
for
cancer Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible signs and symptoms include a lump, abnormal b ...
. He suggested Keyworth demand a review by the
Joint Chiefs of Staff The Joint Chiefs of Staff (JCS) is the body of the most senior uniformed leaders within the United States Department of Defense, that advises the president of the United States, the secretary of defense, the Homeland Security Council and the ...
or resign. Keyworth did neither, prompting Reis to resign a short time later, taking a position at SAIC. After a year of presentations from the Heritage group and others, on 23 March 1983 Reagan went on television and announced that he was calling "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." Many historical overviews place much of the impetus for this speech directly on Teller and Wood's presentations, and thus indirectly on Hagelstein's work. On the same day the president was giving his speech, the Department of Defense was presenting its report to the Senate on the progress of DARPA's ongoing beam weapon research. The director of the Directed Energy Program said that while they offered promise, their "relative immaturity" made it difficult to know if they would ever be used, and in any event would be unlikely to have any effect until the "1990s or beyond". The Undersecretary of Defense, Richard DeLauer, later said these weapons were at least two decades away and development would have "staggering" costs. The Secretary of Defense,
Caspar Weinberger Caspar Willard Weinberger (August 18, 1917 – March 28, 2006) was an American statesman and businessman. As a prominent Republican, he served in a variety of state and federal positions for three decades, including chairman of the Californ ...
formed the Strategic Defense Initiative Office in April 1984, appointing General
James Abrahamson James Alan Abrahamson (born May 19, 1933) is a retired U.S. Air Force general who served as a designated astronaut, associate director of NASA and former director of President Ronald Reagan's Strategic Defense Initiative from 1984 until 1989. H ...
as its head. Early estimates were for a budget of $26billion over the first five years.


Further tests, instrumentation issues

Only a few days after Reagan's speech, on 26 March 1983, the second test of Hagelstein's design was carried out as part of the ''Cabra'' shot in the
Operation Phalanx The United States's Phalanx nuclear test series was a group of 18 nuclear tests conducted in 1982–1983. These tests A bomb test may be a salvo test, defined as two or more explosions "where a period of time between successive individual expl ...
test series. Instrumentation again proved to be a problem and no good results were obtained. The identical experiment was carried out on 16 December 1983 in the ''Romano'' shot of the following
Operation Fusileer Operation Fusileer was a series of 16 nuclear tests conducted by the United States in 1983–1984 at the Nevada Test Site. These tests followed the ''Operation Phalanx The United States's Phalanx nuclear test series was a group of 18 nuc ...
series. This test showed gain and lasing. On 22 December 1983, Teller wrote a letter on LLNL letterhead to Keyworth saying the system had concluded its scientific phase and was now "entering engineering phase". When Woodruff learned of the letter he stormed into Teller's office and demanded a retraction. Teller refused, so Woodruff wrote his own, only to be ordered not to send it by
Roger Batzel Roger is a given name, usually masculine, and a surname. The given name is derived from the Old French personal names ' and '. These names are of Germanic origin, derived from the elements ', ''χrōþi'' ("fame", "renown", "honour") and ', ' ( ...
, the lab's director. Batzel rebuffed Woodruff's complaints, saying Teller was meeting the president as a private citizen, not on behalf of Livermore. Shortly after, LLNL scientist George Maenchen circulated a memo noting that the instrument used to measure the laser output was subject to interactions with the explosion. The system worked by measuring the brightness of a series of
beryllium Beryllium is a chemical element with the symbol Be and atomic number 4. It is a steel-gray, strong, lightweight and brittle alkaline earth metal. It is a divalent element that occurs naturally only in combination with other elements to form mi ...
reflectors when they were illuminated by the lasers. Maenchen noted that the reflectors themselves could give off their own signals when heated by the bomb, and unless they were separately calibrated, there was no way to know if the signal was from the laser or the bomb. This calibration had not been carried out, rendering the results of all of these tests effectively useless. By this time, Los Alamos had begun developing nuclear anti-missile weapons of its own, updated versions of the 1960s
Casaba/Howitzer Project Casaba-Howitzer was a 1960s-era study into the use of nuclear weapons as the drivers for intense beams of plasma for use in space warfare. The basic concept grew out of work on the Project Orion spaceship concept, which studied nuclear s ...
concepts. Given the constant stream of news about Excalibur, they added a laser to one of their own underground tests, shot ''Correo'', also part of the Fusileer series. The 2August 1984 test used different methods to measure the laser output, and these suggested that little or no lasing was taking place. George Miller received a "caustic" letter from Paul Robinson of Los Alamos, which stated they "doubted the existence of the X-ray laser had been demonstrated and that Livermore managers were losing their credibility because of their failure to stand up to Teller and Wood."


Concerned Scientists present concerns

The Union of Concerned Scientists presented a criticism of Excalibur in 1984 as part of a major report on the entire SDI concept. They noted that a key problem for all the directed energy weapons is that they work only in space, as the atmosphere quickly disperses the beams. This meant the systems had to intercept the missiles when they were above the majority of the atmosphere. Additionally, all of the systems relied on using infrared tracking of the missiles, as radar tracking could be easily rendered unreliable using a wide variety of countermeasures. Thus, the interception had to take place in the period where the missile motor was still firing. This left only a brief period in which the directed energy weapons could be used. The report said this could be countered by simply increasing the thrust of the missile. Existing missiles fired for about three to four minutes, with at least half of that taking place outside the atmosphere. They showed it was possible to reduce this to about a minute, timing things so the motor was burning out just as the missile was reaching the upper atmosphere. If the warheads were quickly separated at that point, the defense would have to shoot at the individual warheads, thus facing the same poor cost-exchange ratios that had made the earlier ABM systems effectively useless. And once the rocket had stopped firing, tracking would be far more difficult. One of the key claims for the Excalibur concept was that a small number of weapons would be enough to counter a large Soviet fleet, whereas the other space-based systems would require huge fleets of satellites. The report singled out Excalibur as particularly vulnerable to the problem of quick-firing missiles because the only way to address this would be to build many more weapons so more would be available in the remaining short time window. At that point, it no longer had any advantage over the other systems, while still having all of the technical risks. The report concluded that the X-ray laser would "offer no prospect of being a useful component" of a BMD system.


Excalibur+ and Super-Excalibur

Faced with the twin problems of the original experiments apparently failing and the publication of a report showing that it could be easily defeated even if it worked, Teller and Wood responded by announcing the Excalibur Plus concept, which would be a thousand times more powerful than the original Excalibur. Soon after, they added Super-Excalibur, which was another thousand times more powerful than Excalibur Plus, making it a trillion times as bright as the bomb itself. Super-Excalibur would be so powerful it would be able to burn through the atmosphere, thereby countering the concerns about fast-firing missiles. The extra power also meant it could be divided up into more beams, making a single weapon able to be directed into as many as a hundred thousand beams. Instead of dozens of Excalibur weapons in pop-up launchers, Teller suggested that a single weapon in
geostationary orbit A geostationary orbit, also referred to as a geosynchronous equatorial orbit''Geostationary orbit'' and ''Geosynchronous (equatorial) orbit'' are used somewhat interchangeably in sources. (GEO), is a circular geosynchronous orbit in altitud ...
"the size of an executive desk which applied this technology could potentially shoot down the entire Soviet land-based missile force if it were to be launched into the module's field of view." At this point, no detailed theoretical work on the concepts had been carried out, let alone any practical tests. In spite of this, Teller once again used LLNL letterhead to write to several politicians telling them of the great advance. This time Teller copied Batzel, but not Woodruff. Once again Woodruff asked to send a counterpoint letter, only to have Batzel refuse to let him send it.


Cottage test

Super-Excalibur was tested on the 23 March 1985 ''Cottage'' shot of
Operation Grenadier Operation Grenadier was a series of 16 nuclear tests conducted by the United States in 1984–1985 at the Nevada Test Site. These tests followed the ''Operation Fusileer'' series and preceded the ''Operation Charioteer'' series. References ...
, exactly two years after Reagan's speech. Once again the test appeared to be successful, and unnamed researchers at the lab were reported to have said the brightness of the beam had been increased six orders of magnitude (i.e. between one and ten million times), a huge advance that would pave the way for a weapon. Teller immediately wrote another letter touting the success of the concept. This time he wrote to
Paul Nitze Paul Henry Nitze (January 16, 1907 – October 19, 2004) was an American politician who served as United States Deputy Secretary of Defense, U.S. Secretary of the Navy, and Director of Policy Planning for the U.S. State Department. He is best kn ...
, the head negotiator of START, and
Robert McFarlane Robert Carl "Bud" McFarlane (July 12, 1937 – May 12, 2022) was an American Marine Corps officer who served as National Security Advisor to President Ronald Reagan from 1983 to 1985. Within the Reagan administration, McFarlane was a leading ar ...
, head of the US National Security Council. Nitze was about to begin negotiations on the
START Start can refer to multiple topics: *Takeoff, the phase of flight where an aircraft transitions from moving along the ground to flying through the air * Starting lineup in sports *Standing start, and rolling start, in an auto race Acronyms *St ...
arms limitations talks. Teller said Super-Excalibur would be so powerful the US should not seriously negotiate on any sort of even footing and that the talks should be delayed because they included limits or outright bans on underground testing, which would make further work on Super-Excalibur almost impossible. Commenting on the results, Wood set an optimistic tone saying, "Where we stand between inception and production I can't tell you... utI am much more optimistic now about the utility of X-ray lasers in strategic defense than when we started." In contrast, George H. Miller, LLNL's new deputy associate director, set a much more cautious tone, stating that while the lasing action had been demonstrated, "what we have not proven is whether you can make a militarily useful X-ray laser. It's a research program where a lot of the physics and engineering issues are still being examined..." Several months later, physicists at Los Alamos reviewed the Cottage results and noted the same problem Maenchen had mentioned earlier. They added such calibration to a test they were already carrying out and found that the results were indeed as bad as Maenchen has suggested. The targets contained
oxygen Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as wel ...
that glowed when heated and produced spurious results. On top of this, Livermore scientists studying the results noted that the explosion created sound waves in the rod before the lasing was complete, ruining the focus of the laser. A new lasing medium would be required. Livermore ordered an independent review of the program by Joseph Nilsen, who delivered a report on 27 June 1985 agreeing the system was not working. Given the gravity of the situation, a further review by the JASONs was carried out on 26 and 27 September and came to the same conclusion. It now appeared there was no conclusive evidence that any lasing had been seen in any of the tests, and if it had, it was simply not powerful enough. In July, Miller went to Washington to brief the SDI Office (SDIO) on their progress. While the instrumentation concerns had been publicly reported on multiple occasions by this point, he failed to mention these issues. Several sources noted this, one saying they "were furious because Miller used the old view graphs on the experiment, which did not take into account the new disturbing findings".


Woodruff leaves

Shortly after the Cottage test, Teller once again met with Reagan. He petitioned the President for an additional $100million in order to carry out additional underground testing the next year, which would roughly double the Excalibur budget for 1986. He said this was needed because the Soviets were stepping up their own research. Later that year, Abrahamson, head of SDIO, called a 6September 1985 meeting to review the status of the programs. Roy Woodruff was there to present LLNL's status. Teller arrived in the middle of the meeting and said Reagan had agreed that $100million should be turned over to Excalibur. Without questioning this, Abrahamson then assigned $100million to him, taking it from other programs. As one official noted, "Do you really want to challenge someone who says he's talked to the President? Do you really want to risk your status by asking Reagan if that's what he really said?" At this point Woodruff, who had attempted to rein in Teller and Wood's continual overselling of the project, finally had enough. He filed a grievance with LLNL management, complaining that Teller and Wood "undercut my management responsibility for the X-ray laser program" and had repeatedly made "optimistic, technically incorrect statements regarding this research to the nation's highest policy-makers". When he learned that Teller and Wood had made another presentation to Abrahamson, on 19 October 1985 he resigned his position and asked to be moved. At the time he said little about it, although there was widespread speculation in the press over why he had quit the program. The lab dismissed press speculation that it was punishment due to a critical review in the influential journal ''Science'' which appeared the same day. Teller refused to talk about the matter, while Woodruff simply pointed reporters to a statement put out by the lab. Woodruff found himself banished to a windowless room he called "Gorky West", referring to the Russian city of Gorky where Soviet dissidents were sent on internal exile. Miller replaced him as associate director. A few months later, Woodruff began receiving condolences from other members of the lab. When he asked why, he was told that Batzel had said he resigned his position due to stress and a
midlife crisis A midlife crisis is a transition of identity and self-confidence that can occur in middle age, middle-aged individuals, typically 40 to 60 years old. The phenomenon is described as a psychological crisis brought about by events that highlight a pe ...
. Woodruff went to Harold Weaver, head of the Berkeley-based lab oversight committee, to tell his side of the story. He learned that the group had already investigated, by sending a liaison to meet with Batzel, but had not bothered to talk to Woodruff. He attempted to explain his concerns about the overselling of the technology, but as Weaver later put it, "we were bamboozled by the laboratory."


Increased scrutiny

Starting in late 1985 and through 1986, a series of events turned opinion against Excalibur. One of the many arguments used to support Excalibur, and SDI as a whole, was the suggestion that the Soviets were working on the same ideas. In particular, they said the Soviets published numerous papers on X-ray lasers until 1977 when they suddenly stopped. They argued this was because they had also begun a military X-ray laser program, and were now classifying their reports. Wood used this line of argument during congressional meetings on SDI as an argument to keep funding Excalibur. He was then asked to expand on the possibility of a Soviet version of Excalibur and what a US response might be. Wood said X-ray lasers could be used against any object in space, including Soviet Excaliburs, referring to this use as a "counter-defensive" role. This statement was quickly turned against him; if Excalibur could destroy a Soviet SDI system, then a Soviet Excalibur could do the same to theirs. Instead of ending the threat of nuclear weapons, Excalibur appeared to end the threat of SDI. More worryingly, when one considered such scenarios, it appeared the best use of such a system would be to launch a first strike; Soviet Excaliburs would destroy US defenses while their ICBMs attacked the US missile fleet in their
missile silo A missile launch facility, also known as an underground missile silo, launch facility (LF), or nuclear silo, is a vertical cylindrical structure constructed underground, for the storage and launching of intercontinental ballistic missiles (ICBMs ...
s, the remaining Soviet Excaliburs would then blunt the enfeebled response. Miller immediately sent a letter countering Wood's statements, but the damage was done. Shortly thereafter, Hugh DeWitt wrote a letter to ''
The New York Times ''The New York Times'' (''the Times'', ''NYT'', or the Gray Lady) is a daily newspaper based in New York City with a worldwide readership reported in 2020 to comprise a declining 840,000 paid print subscribers, and a growing 6 million paid ...
'' about Excalibur. He explained the actual state of the program, saying it was "still in its infancy" and that developing it completely "might require 100 to 1200 more nuclear tests and could easily require ten to twenty more years". DeWitt and
Ray Kidder Ray E. Kidder () was an American physicist and nuclear weapons designer. He is best known for his outspoken views on nuclear weapons policy issues, including nuclear testing, stockpile management, and arms control. Kidder was a weapons physic ...
then wrote to
Edward Kennedy Edward Moore Kennedy (February 22, 1932 – August 25, 2009) was an American lawyer and politician who served as a United States senator from Massachusetts for almost 47 years, from 1962 until his death in 2009. A member of the Democratic ...
and
Ed Markey Edward John Markey (born July 11, 1946) is an American lawyer, politician, and former Army reservist who has served as the junior United States senator from Massachusetts since 2013. A member of the Democratic Party, he was the U.S. representa ...
to complain that LLNL's objection to ongoing talks of a nuclear test ban rested solely on the X-ray program.


Focusing failures

While this was taking place in the press, LLNL was preparing for another test shot, ''Goldstone'', a part of
Operation Charioteer Operation Charioteer was a series of 16 nuclear tests conducted by the United States in 1985–1986 at the Nevada Test Site. These tests followed the ''Operation Grenadier Operation Grenadier was a series of 16 nuclear tests conducted by ...
scheduled for December 1985. After the problems with the earlier tests were noted, Los Alamos had suggested LLNL design a new sensor for this shot. LLNL refused, saying this would delay the test about six months and would have "unfavorable political repercussions for the program". Instead, Goldstone used a new reflector consisting of hydrogen gas which would address the calibration concerns. The new instruments demonstrated that the output of the lasers was at best ten percent of what the theoretical predictions required, and at worst, had produced no laser output at all. Focusing was the primary concern of the next test, ''Labquark'', carried out on 20 September 1986. This was apparently successful, suggesting the major problems with focusing had been addressed. A follow-up focusing test, ''Delamar'', was carried out on 18 April 1987. This test demonstrated that the focusing in both this test and Labquark appeared to be an illusion; the beam had not narrowed and was not focused enough for long-range interceptions. When the news broke, Teller blamed Woodruff, saying he had not been "a constructive member of the team". Teller continued to say the tests were actually a success, but that he was prevented from telling the real story due to government secrecy.


APS report on directed energy weapons

In 1984 the
American Physical Society The American Physical Society (APS) is a not-for-profit membership organization of professionals in physics and related disciplines, comprising nearly fifty divisions, sections, and other units. Its mission is the advancement and diffusion of k ...
(APS) approached Keyworth with the idea of setting up a
blue-ribbon panel In the United States, a blue-ribbon committee (or panel or commission) is a group of exceptional people appointed to investigate, study or analyze a given question. Blue-ribbon committees generally have a degree of independence from political infl ...
to study the various weapons concepts independent of the labs. Keyworth and Abrahamson both agreed with this idea, giving the team complete access to classified materials as required. The APS panel took almost a year to form, and was co-chaired by
Nicolaas Bloembergen Nicolaas Bloembergen (March 11, 1920 – September 5, 2017) was a Dutch-American physicist and Nobel laureate, recognized for his work in developing driving principles behind nonlinear optics for laser spectroscopy. During his career, he was a p ...
, who won the 1981
Nobel Prize in Physics ) , image = Nobel Prize.png , alt = A golden medallion with an embossed image of a bearded man facing left in profile. To the left of the man is the text "ALFR•" then "NOBEL", and on the right, the text (smaller) "NAT•" then " ...
for his work on lasers, and
Kumar Patel Chandra Kumar Naranbhai Patel (born 2 July 1938) is an electrical engineer. He developed the carbon dioxide laser in 1963; it is now widely used in industry for cutting and engraving a wide range of materials like plastic and wood. Because th ...
, who had invented the CO2 laser. The sixteen other members of the panel were similarly distinguished. The report was completed in eighteen months, but due to the classified contents, it required about another seven months to clear the censors before the redacted version was released to the public in June 1987. The report, "The Science and Technology of Directed Energy Weapons", stated that the technologies in question were at least a decade away from the stage where it could be clearly stated whether or not they would even work. Some of the systems appeared to be theoretically possible but needed more development. This was the case for the
free electron laser A free-electron laser (FEL) is a (fourth generation) light source producing extremely brilliant and short pulses of radiation. An FEL functions and behaves in many ways like a laser, but instead of using stimulated emission from atomic or molecula ...
, for instance, where the panel was able to offer specific information on the required improvements, calling for two or more
orders of magnitude An order of magnitude is an approximation of the logarithm of a value relative to some contextually understood reference value, usually 10, interpreted as the base of the logarithm and the representative of values of magnitude one. Logarithmic dis ...
in energy (100 times). In contrast, the report's section on Excalibur suggested it was not clear it could ever work even in theory and was summarized thus: The report also noted that the energy requirements for a directed energy weapon used as a BMD asset was much higher than the energy needed for the same weapon to be used against those assets. This meant even if the SDI weapons could be successfully developed, they could be attacked by similar weapons that would be easier to develop. The movement of space-based assets in well-known orbital paths also made them much easier to attack and exposed to attack for longer times compared to the same systems being used to attack ICBMs, whose initial positions were unknown and disappeared in minutes. The report noted this was particularly true of pop-up X-ray lasers. They noted that: A specific concern, in this case, was the susceptibility of the optics, and especially their
optical coating An optical coating is one or more thin layers of material deposited on an optical component such as a lens, prism or mirror, which alters the way in which the optic reflects and transmits light. These coatings have become a key technology in th ...
s, of the various space-based weapons. Even relatively low-intensity laser light could damage these devices, blinding their optics and rendering the weapons unable to track their targets. Given the light weight of the Excalibur-type weapons, the Soviets could rapidly pop-up such a device just prior to launching an attack, and blind all the SDI assets in the region even with a low-powered weapon.


Woodruff affair, GAO report

During the later half of 1987, Woodruff found that no work was being assigned to him. With little to do, the lab threatened to cut his salary. On 2February 1987, Batzel gave him a memo saying any problems he had were his own making. His final appeal, to the university president David Gardner, was likewise turned down. In response, in April 1987 Woodruff filed two official grievances. This prompted a private review by
John S. Foster Jr. John Stuart Foster Jr. (born September 18, 1922) is an American physicist, best known as the fourth director of Lawrence Livermore National Laboratory and as Director, Defense Research and Engineering under four Secretaries of Defense and two Pr ...
and
George Dacey George Clement Dacey (1921–2010) was an American scientist and inventor who played a key role in the history of the transistor. Biography He was born in 1921 in Illinois, United States. He was the son of Helen and Clement Dacey. He died i ...
at the urging of the Department of Energy. This report apparently had no effect. The story became known within the labs, and the way Batzel retaliated against Woodruff became a major point of concern among the employees. A number of scientists in the lab were so upset at his treatment they wrote an April 1987 letter about it to Gardner. When they asked for people to sign the cover letter, they were "practically stampeded" by volunteers. This was one of many signs of growing turmoil in the labs. In October 1987, someone sent a copy of Woodruff's grievance to the
Federation of American Scientists The Federation of American Scientists (FAS) is an American nonprofit global policy think tank with the stated intent of using science and scientific analysis to attempt to make the world more secure. FAS was founded in 1946 by scientists who wo ...
, who then turned it over to the newspapers. Woodruff was visiting Los Alamos when the first stories came in over the
Associated Press The Associated Press (AP) is an American non-profit news agency headquartered in New York City. Founded in 1846, it operates as a cooperative, unincorporated association. It produces news reports that are distributed to its members, U.S. newspa ...
wire, which resulted in a standing ovation by the other scientists. The press, now largely turned against SDI, made it a major issue they came to refer to as the "Woodruff Affair". The press articles on the topic, which were generally more widespread in California newspapers, came to the attention of California Congressman
George Brown Jr. George Edward Brown Jr. (March 6, 1920 – July 15, 1999) was an American Democratic politician from California. He represented suburban portions of Los Angeles County in the United States House of Representatives from 1963 to 1971 and parts of ...
Brown triggered an investigation by the
General Accounting Office The U.S. Government Accountability Office (GAO) is a legislative branch government agency that provides auditing, evaluative, and investigative services for the United States Congress. It is the supreme audit institution of the federal gover ...
(GAO). Brown later said Teller's version of events was "politically motivated exaggerations aimed at distorting national policy and funding decisions". The GAO report stated that they found a wide variety of opinions on the X-ray laser project, but Teller and Wood were "essentially off the scale on the optimistic side". They noted that Woodruff's attempts to correct these statements were blocked and that his complaints about the lab's behavior resulted in him becoming what the lab insider called a "nonperson" in which longtime colleagues stopped talking to him. But the report also generally agreed with the lab on most other points, and then went on to accuse Woodruff of falsely stating he was a member of
Phi Beta Kappa The Phi Beta Kappa Society () is the oldest academic honor society in the United States, and the most prestigious, due in part to its long history and academic selectivity. Phi Beta Kappa aims to promote and advocate excellence in the liberal a ...
. It was later revealed that a letter submitted by Ray Kidder for inclusion in the report had been removed. Kidder strongly agreed with Woodruff's version of events and said Woodruff's attempt to send letters "provided a frank, objective and balanced description of the Program as it existed at the time". Batzel had already decided to retire by this time, and his position was filled by
John Nuckolls John Hopkin Nuckolls (born 17 November 1930) is an American physicist who worked his entire career at the Lawrence Livermore National Laboratory. He is best known for the development of inertial confinement fusion, which is a major branch of fusio ...
. Nuckolls gave Woodruff the position as an assistant associate director for treaty verification efforts, a position of some importance as SDI began to wind down while at the same time new treaties made such verification efforts important. Nevertheless, in 1990 Woodruff left to take a position at Los Alamos. As Woodruff had feared, the end result was to seriously erode the reputation of LLNL in the government. John Harvey, LLNL's director for advanced strategic systems, found that when he visited Washington he was asked: "what's the next lie that's going to come out?" Brown later commented: "I'm not inclined to call it an earthshattering report, but what has happened has created a lot of questions about the objectivity and reliability of the laboratory."


Excalibur ends

By 1986 it was reported that the SDIO saw Excalibur primarily as an anti-satellite weapon, and perhaps useful as a discrimination tool to tell warheads from decoys. This, along with the results from the most recent tests, made it clear it was no longer considered to be useful as a BMD weapon on its own. By the late 1980s, the entire concept was being derided in the press and by other members of the lab; ''The New York Times'' quoted George Maenchen as stating "All these claims are totally false. They lie in the realm of pure fantasy." The stories prompted a ''
60 Minutes ''60 Minutes'' is an American television news magazine broadcast on the CBS television network. Debuting in 1968, the program was created by Don Hewitt and Bill Leonard, who chose to set it apart from other news programs by using a unique styl ...
'' interview with Teller, but when they began to question him on Woodruff, Teller attempted to rip off the microphone. Funding for Excalibur peaked in 1987 at $349million and then began to rapidly reverse. The March 1988 budget ended development as a weapon system, and the original R group was shut down. In the 1990 budget, Congress eliminated it as a separate item. X-ray laser research continued at LLNL, but as a purely scientific project, not as a weapons program. Another test, ''Greenwater'', had already been planned but was ultimately canceled. In total, ten underground tests were used in the development program.


Brilliant Pebbles begins

With Excalibur effectively dead, in 1987 Teller and Wood began pitching Wood's new concept,
Brilliant Pebbles Brilliant Pebbles was a Missile defense, ballistic missile defense (BMD) system proposed by Lowell Wood and Edward Teller of the Lawrence Livermore National Laboratory (LLNL) in 1987, near the end of the Cold War. The system would consist of tho ...
. They first presented this to Abrahamson in October and followed up with a March 1988 meeting with Reagan and his aides. The new concept used a fleet of about a hundred thousand small independent rockets weighing about each to destroy the missiles or warheads by colliding with them, no explosive required. Because they were independent, attacking them would require an equally huge number of interceptors. Better yet, the entire system could be developed in a few years and would cost $10billion for a complete fleet. Brilliant Pebbles was essentially an updated version of the Project BAMBI concepts Graham had been suggesting in 1981. At that time, Teller had continually derided the idea as "outlandish" and used his influence to ensure the concept did not receive serious attention. Ignoring his previous concerns with the concept, Teller went on to promote Brilliant Pebbles using arguments he had previously dismissed when raised about Excalibur; among them, he now stressed that the system did not place or explode nuclear weapons in space. When critics said the idea fell prey to the issues raised by the Union of Concerned Scientists, Teller simply ignored them. In spite of all of these red flag issues, and the decades-long string of Air Force and DARPA reports suggesting the concept just would not work, Reagan once again enthusiastically embraced their latest concept. By 1989 the weight of each pebble had grown to and the cost of a small fleet of 4,600 of them had ballooned to $55billion. It remained the centerpiece of the US BMD efforts into 1991 when the numbers were further cut to somewhere between 750 and 1,000.
President Clinton William Jefferson Clinton ( né Blythe III; born August 19, 1946) is an American politician who served as the 42nd president of the United States from 1993 to 2001. He previously served as governor of Arkansas from 1979 to 1981 and again ...
indirectly canceled the project on 13 May 1993 when the SDI office was reorganized as the
Ballistic Missile Defense Organization The Ballistic Missile Defense Organization (BMDO) 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 was renamed the Missile Defense Agenc ...
(BMDO) and focused their efforts on
theater ballistic missile A theatre ballistic missile (TBM) is any ballistic missile with a range less than , used against targets " in-theatre". Its range is thus between that of tactical and intermediate-range ballistic missiles. The term is a relatively new one, encomp ...
s.


Teller, SDI and Reykjavík

Throughout SDI's history, journalist
William Broad William J. Broad (born March 7, 1951) is an American science journalist, author and a Senior Writer at ''The New York Times''. Education Broad earned a master's degree from the University of Wisconsin in 1977.he nickname for SDI" In particular, Broad points to the meeting between Teller and Reagan in September 1982 as the key moment in SDI's creation. Years later, Broad described the meeting this way: "For half an hour, Teller deployed X-ray lasers all over the Oval Office, reducing hundreds of incoming Soviet missiles to radioactive chaff, while Reagan, gazing up ecstatically, saw a crystal shield, covering the Last Hope of Man." This basic telling of the story is recounted in other contemporary sources; in their biography, ''Edward Teller: Giant of The Golden Age of Physics'', Blumberg and Panos essentially make the same statement, as does Robert Park in his '' Voodoo Science''. Others give less credence to Teller's persuasive capabilities; Ray Pollock, who was present at the meeting, described in a 1986 letter that "I sat in on the mid-September 1982 meeting Teller had in the Oval Office... Teller got a warm reception but that is all. I had the feeling he confused the president." In particular, he notes Teller's opening comment about "Third generation, third generation!" as being a point of confusion. Keyworth was later quoted as calling the meeting "a disaster". Others report that Teller's bypassing of official channels to arrange the meeting angered Caspar Weinberger and other members of the Department of Defense. Others debate Excalibur's role in SDI from the start. Park suggests that Reagan's "kitchen cabinet" was pushing for some sort of action on BMD even before this period. Charles Townes suggested the key impetus to move forward was not Teller, but a presentation by the Joint Chiefs of Staff made only a few weeks before his speech that suggested shifting some development funding to defensive systems. Reagan mentioned this during the speech introducing SDI. Nigel Hey points to Robert McFarlane and the
United States National Security Council The United States National Security Council (NSC) is the principal forum used by the President of the United States for consideration of national security, military, and foreign policy matters. Based in the White House, it is part of the Execu ...
as a whole. In a 1999 interview with Hey, Teller himself would suggest that he had little to do with the president's decision to announce SDI. He also did not want to talk about the X-ray laser and said he did not even recognize the name "Excalibur". There is considerable debate on whether or not Excalibur had a direct effect on the failure of the Reykjavík Summit. During the October 1986 meeting, Reagan and
Mikhail Gorbachev Mikhail Sergeyevich Gorbachev (2 March 1931 – 30 August 2022) was a Soviet politician who served as the 8th and final leader of the Soviet Union from 1985 to dissolution of the Soviet Union, the country's dissolution in 1991. He served a ...
initially considered the issue of the destabilizing effect of intermediate-range missiles in Europe. As both proposed various ideas to eliminate them, they quickly began to ratchet up the numbers and types of weapons being considered. Gorbachev started with his acceptance of Reagan's 1981 "double zero option" for intermediate-range missiles but then countered with an additional offer to eliminate fifty percent of all nuclear-armed missiles. Reagan then countered with an offer to eliminate all such missiles within ten years, as long as the US was free to deploy defensive systems after that period. At that point, Gorbachev offered to eliminate all nuclear weapons of any sort within that same time period. At this point SDI came into the negotiations. Gorbachev would consider such a move only if the US limited their SDI efforts to the laboratory for ten years. Excalibur, which Teller's letter of only a few days earlier once again said was ready to enter engineering, would need to be tested in space before that point. Reagan refused to back down on this issue, as did Gorbachev. Reagan attempted one last time to break the logjam, asking if he would really "turn down a historic opportunity because of a single word" ("laboratory"). Gorbachev said it was a matter of principle; if the US continued real-world testing while the Soviets agreed to dismantle their weapons, he would return to Moscow to be considered a fool.


Physics


Lasers

Laser A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The word "laser" is an acronym for "light amplification by stimulated emission of radiation". The fir ...
s rely on two physical phenomena to work, '' stimulated emission'' and ''
population inversion In science, specifically statistical mechanics, a population inversion occurs while a system (such as a group of atoms or molecules) exists in a state in which more members of the system are in higher, excited states than in lower, unexcited energy ...
''. An atom is made of a
nucleus Nucleus ( : nuclei) is a Latin word for the seed inside a fruit. It most often refers to: *Atomic nucleus, the very dense central region of an atom * Cell nucleus, a central organelle of a eukaryotic cell, containing most of the cell's DNA Nucl ...
and a number of
electron The electron ( or ) is a subatomic particle with a negative one elementary electric charge. Electrons belong to the first generation of the lepton particle family, and are generally thought to be elementary particles because they have no kn ...
s orbiting in shells around it. Electrons can be found in many discrete energy states, defined by
quantum mechanics Quantum mechanics is a fundamental theory in physics that provides a description of the physical properties of nature at the scale of atoms and subatomic particles. It is the foundation of all quantum physics including quantum chemistry, ...
. The energy levels depend on the structure of the nucleus, so they vary from element to element. Electrons can gain or lose energy by absorbing or emitting a
photon A photon () is an elementary particle that is a quantum of the electromagnetic field, including electromagnetic radiation such as light and radio waves, and the force carrier for the electromagnetic force. Photons are massless, so they always ...
with the same energy as the difference between two allowable energy states. This is why different elements have unique
spectrum A spectrum (plural ''spectra'' or ''spectrums'') is a condition that is not limited to a specific set of values but can vary, without gaps, across a continuum. The word was first used scientifically in optics to describe the rainbow of colors i ...
s and gives rise to the science of
spectroscopy Spectroscopy is the field of study that measures and interprets the electromagnetic spectra that result from the interaction between electromagnetic radiation and matter as a function of the wavelength or frequency of the radiation. Matter wa ...
. Electrons will naturally release photons if there is an unoccupied lower energy state. An isolated atom would normally be found in the
ground state The ground state of a quantum-mechanical system is its stationary state of lowest energy; the energy of the ground state is known as the zero-point energy of the system. An excited state is any state with energy greater than the ground state. ...
, with all of its electrons in their lowest possible state. But due to the surrounding environment adding energy, the electrons will be found in a range of energies at any given instant. Electrons that are not in the lowest possible energy state are known as "excited", as are the atoms that contain them. Stimulated emission occurs when an excited electron can drop by the same amount of energy as a passing photon. This causes a second photon to be emitted, closely matching the original's energy, momentum, and phase. Now there are two photons, doubling the chance that they will cause the same reaction in other atoms. As long as there is a large population of atoms with electrons in the matching energy state, the result is a
chain reaction A chain reaction is a sequence of reactions where a reactive product or by-product causes additional reactions to take place. In a chain reaction, positive feedback leads to a self-amplifying chain of events. Chain reactions are one way that syst ...
that releases a burst of single-frequency, highly
collimated light A collimated beam of light or other electromagnetic radiation has parallel rays, and therefore will spread minimally as it propagates. A perfectly collimated light beam, with no divergence, would not disperse with distance. However, diffraction ...
. The process of gaining and losing energy is normally random, so under typical conditions, a large group of atoms is unlikely to be in a suitable state for this reaction. Lasers depend on some sort of setup that results in many electrons being in the desired states, a condition known as a population inversion. An easy to understand example is the
ruby laser A ruby laser is a solid-state laser that uses a synthetic ruby crystal as its gain medium. The first working laser was a ruby laser made by Theodore H. "Ted" Maiman at Hughes Research Laboratories on May 16, 1960. Ruby lasers produce pulses of c ...
, where there is a
metastable state In chemistry and physics, metastability denotes an intermediate energetic state within a dynamical system other than the system's state of least energy. A ball resting in a hollow on a slope is a simple example of metastability. If the ball i ...
where electrons will remain for a slightly longer period if they are first excited to even higher energy. This is accomplished through optical pumping, using the white light of a flash lamp to increase the electron energy to a blue-green or ultraviolet frequency. The electrons then rapidly lose energy until they reach the metastable energy level in the deep red. This results in a brief period where a large number of electrons lie at this medium energy level, resulting in a population inversion. At that point any one of the atoms can emit a photon at that energy, starting the chain reaction.


X-ray lasers

An X-ray laser works in the same general fashion as a ruby laser, but at much higher energy levels. The main problem in producing such a device is that the probability of any given transition between energy states depends on the cube of the energy. Comparing a ruby laser that operates at 694.3 nm to a hypothetical soft X-ray laser that might operate at 1nm, this means the X-ray transition is 694, or a little over 334million times less likely. To provide the same total output energy, one needs a similar increase in input energy. Another problem is that the excited states are extremely short-lived: for a 1nm transition, the electron will remain in the state for about 10 seconds. Without a
metastable state In chemistry and physics, metastability denotes an intermediate energetic state within a dynamical system other than the system's state of least energy. A ball resting in a hollow on a slope is a simple example of metastability. If the ball i ...
to extend this time, this means there is only this fleeting time, much less than a '' shake'', to carry out the reaction. A suitable substance with a metastable state in the X-ray region is unknown in the open literature. Instead, X-ray lasers rely on the speed of various reactions to create the population inversion. When heated beyond a certain energy level, electrons dissociate from their atoms entirely, producing a gas of nuclei and electrons known as a
plasma Plasma or plasm may refer to: Science * Plasma (physics), one of the four fundamental states of matter * Plasma (mineral), a green translucent silica mineral * Quark–gluon plasma, a state of matter in quantum chromodynamics Biology * Blood pla ...
. Plasma is a gas, and its energy causes it to adiabatically expand according to the
ideal gas law The ideal gas law, also called the general gas equation, is the equation of state of a hypothetical ideal gas. It is a good approximation of the behavior of many gases under many conditions, although it has several limitations. It was first stat ...
. As it does, its temperature drops, eventually reaching a point where the electrons can reconnect to nuclei. The cooling process causes the bulk of the plasma to reach this temperature at roughly the same time. Once reconnected to nuclei, the electrons lose energy through the normal process of releasing photons. Although rapid, this release process is slower than the reconnection process. This results in a brief period where there are a large number of atoms with the electrons in the high-energy just-reconnected state, causing a population inversion. To produce the required conditions, a huge amount of energy needs to be delivered extremely rapidly. It has been demonstrated that something on the order of 1watt ''per atom'' is needed to provide the energy required to produce an X-ray laser. Delivering so much energy to the lasing medium invariably means it will be vaporized, but the entire reaction occurs so rapidly this is not necessarily a problem. It does imply such systems will be inherently one-shot devices. Finally, another complication is that there is no effective mirror for X-ray frequency light. In a common laser, the lasing medium is normally placed between two partial mirrors that reflect some of the output back into the medium. This greatly increases the number of photons in the medium and increases the chance that any given atom will be stimulated. More importantly, as the mirrors reflect only those photons traveling in a particular direction, and the stimulated photons will be released in the same direction, this causes the output to be highly focused. Lacking either of these effects, the X-ray laser has to rely entirely on stimulation as the photons travel through the medium only once. To increase the odds that any given photon causes stimulation, and to focus the output, X-ray lasers are designed to be very long and skinny. In this arrangement, most of the photons being released naturally through conventional emissions in random directions will simply exit the medium. Only those photons that happen to be released traveling down the long axis of the medium have a reasonable chance of stimulating another release. A suitable lasing medium would have an aspect ratio on the order of 10,000.


Excalibur

Although most details of the Excalibur concept remain classified, articles in ''
Nature Nature, in the broadest sense, is the physics, physical world or universe. "Nature" can refer to the phenomenon, phenomena of the physical world, and also to life in general. The study of nature is a large, if not the only, part of science. ...
'' and ''
Reviews of Modern Physics ''Reviews of Modern Physics'' (abbreviated RMP) is a quarterly peer-reviewed scientific journal published by the American Physical Society. It was established in 1929 and the current editor-in-chief is Michael Thoennessen. The journal publishes r ...
'', along with those in optics-related journals, contain broad outlines of the underlying concepts and outline possible ways to build an Excalibur system. The basic concept would require one or more lasing rods arranged into a module along with a tracking camera. These would be arranged on a framework surrounding the nuclear weapon in the center. ''Natures description shows multiple lasing rods embedded in a plastic matrix forming a cylinder around the bomb and tracking device, meaning each device would be able to attack a single target. The accompanying text, however, describes it as having several aimable modules, perhaps four. Most other descriptions show multiple modules arranged around the bomb that can be separately aimed, which more closely follows the suggestions of there being several dozen such lasers per device. In order to damage the airframe of an ICBM, an estimated 3kJ/cm2 would need to hit it. The laser is essentially a focusing device, taking the radiation falling along the length of the rod and turning some small amount of it into a beam traveling out the end. One can consider the effect as increasing the brightness of the X-rays falling on the target compared to the X-rays released by the bomb itself. The enhancement of the brightness compared to the unfocused output from the bomb is \eta/d\theta, where \eta is the efficiency of conversion from bomb X-rays to laser X-rays, and d\theta is the dispersion angle. If a typical ICBM is in diameter, at a distance of represents a
solid angle In geometry, a solid angle (symbol: ) is a measure of the amount of the field of view from some particular point that a given object covers. That is, it is a measure of how large the object appears to an observer looking from that point. The poi ...
of 10−12
steradian The steradian (symbol: sr) or square radian is the unit of solid angle in the International System of Units (SI). It is used in three-dimensional geometry, and is analogous to the radian, which quantifies planar angles. Whereas an angle in radian ...
(sr). Estimates of the dispersion angles from the Excalibur lasers were from 10−12 to 10−9. Estimates of \eta vary from about 10−5 to 10−2; that is, they have laser gain less than one. In the worst-case scenario, with the widest dispersion angle and the lowest enhancement, the pump weapon would have to be approximately 1MT for a single laser to deposit enough energy on the booster to be sure to destroy it at that range. Using best-case scenarios for both values, about 10kT are required. The exact material of the lasing medium has not been specified. The only direct statement from one of the researchers was by Chapline, who described the medium on the original Diablo Hawk test being "an organic pith material" from a weed growing on a vacant lot in Walnut Creek, a town a short distance away from Livermore. Various sources describe the later tests using metals; selenium, zinc and aluminum have been mentioned specifically.


BMD


Missile-based systems

The US Army ran an ongoing BMD program dating from the 1940s. This was initially concerned with shooting down
V-2 The V-2 (german: Vergeltungswaffe 2, lit=Retaliation Weapon 2), with the technical name ''Aggregat 4'' (A-4), was the world’s first long-range guided ballistic missile. The missile, powered by a liquid-propellant rocket engine, was develope ...
-like targets, but an early study on the topic by
Bell Labs Nokia Bell Labs, originally named Bell Telephone Laboratories (1925–1984), then AT&T Bell Laboratories (1984–1996) and Bell Labs Innovations (1996–2007), is an American industrial research and scientific development company owned by mult ...
suggested their short flight times would make it difficult to arrange an interception. The same report noted that the longer flight times of long-range missiles made this task simpler, in spite of various technical difficulties due to higher speeds and altitudes. This led to a series of systems starting with
Nike Zeus Nike Zeus was an anti-ballistic missile (ABM) system developed by the US Army during the late 1950s and early 1960s that was designed to destroy incoming Soviet intercontinental ballistic missile warheads before they could hit their targets. It ...
, then
Nike-X Nike-X was an anti-ballistic missile (ABM) system designed in the 1960s by the United States Army to protect major cities in the United States from attacks by the Soviet Union's intercontinental ballistic missile (ICBM) fleet during the Cold War ...
,
Sentinel Sentinel may refer to: Places Mountains * Mount Sentinel, a mountain next to the University of Montana in Missoula, Montana * Sentinel Buttress, a volcanic crag on James Ross Island, Antarctica * Sentinel Dome, a naturally occurring grani ...
and finally the
Safeguard Program The Safeguard Program was a U.S. Army anti-ballistic missile (ABM) system designed to protect the U.S. Air Force's Minuteman ICBM silos from attack, thus preserving the US's nuclear deterrent fleet. It was intended primarily to protect against th ...
. These systems used short and medium-range missiles equipped with nuclear warheads to attack incoming enemy ICBM warheads. The constantly changing concepts reflect their creation during a period of rapid changes in the opposing force as the Soviet ICBM fleet was expanded. The interceptor missiles had a limited range, less than , so interceptor bases had to be spread across the United States. Since the Soviet warheads could be aimed at any target, adding a single ICBM, which were becoming increasingly inexpensive in the 1960s, would (theoretically) require another interceptor at every base to counter it. This led to the concept of the
cost-exchange ratio In anti-ballistic missile (ABM) defence the cost-exchange ratio is the ratio of the incremental cost to the aggressor of getting one additional warhead through the defence screen, divided by the incremental cost to the defender of offsetting the ad ...
, the amount of money one had to spend on additional defenses to counter a dollar of new offensive capability. Early estimates were around 20, meaning every dollar the Soviets spent on new ICBMs would require the US to spend $20 to counter it. This implied the Soviets could afford to overwhelm the US's ability to build more interceptors. With MIRV, the cost-exchange ratio was so one-sided there was no effective defense that could not be overwhelmed for little cost, as mentioned in a famous 1968 article by Bethe and Garwin. This is precisely what the US did when the Soviets installed their
A-35 anti-ballistic missile system The A-35 anti-ballistic missile system was a Soviet military anti-ballistic missile (ABM) system deployed around Moscow to intercept enemy ballistic missiles targeting the city or its surrounding areas. The A-35 was the only Soviet ABM system allo ...
around
Moscow Moscow ( , US chiefly ; rus, links=no, Москва, r=Moskva, p=mɐskˈva, a=Москва.ogg) is the capital and largest city of Russia. The city stands on the Moskva River in Central Russia, with a population estimated at 13.0 million ...
; by adding MIRV to the
Minuteman missile The LGM-30 Minuteman is an American land-based intercontinental ballistic missile (ICBM) in service with the Air Force Global Strike Command. , the LGM-30G Minuteman III version is the only land-based ICBM in service in the United States and r ...
fleet, they could overwhelm the A-35 without adding a single new missile.


X-ray based attacks

During high-altitude tests in the late 1950s and early 1960s, it was noticed that the burst of X-rays from a nuclear explosion were free to travel long distances, unlike low altitude bursts where the air interacted with the X-rays within a few tens of meters. This led to new and unexpected effects. It also led to the possibility of designing a bomb specifically to increase the X-ray release, which could be made so powerful the rapid deposit of energy on a metal surface would cause it to explosively vaporize. At ranges on the order of , this would have enough energy to destroy a warhead. This concept formed the basis of the
LIM-49 Spartan The LIM-49 Spartan was a United States Army anti-ballistic missile, designed to intercept attacking nuclear warheads from Intercontinental ballistic missiles at long range and while still outside the atmosphere. For actual deployment, a five-mega ...
missile and its
W71 The W-71 nuclear warhead was a US thermonuclear warhead developed at Lawrence Livermore National Laboratory in California and deployed on the LIM-49A Spartan missile, a component of the Safeguard Program, an anti-ballistic missile (ABM) defense ...
warhead. Due to the large volume in which the system was effective, it could be used against warheads hidden among radar decoys. When decoys are deployed along with the warhead they form a ''threat tube'' about a wide and as much as ten miles long. Previous missiles had to get within a few hundred yards (meters) to be effective, but with Spartan, one or two missiles could be used to attack a warhead anywhere within this cloud of material. This also greatly reduced the accuracy needed for the missile's guidance system; the earlier Zeus had a maximum effective range of about due to the limits of the resolution of the
radar Radar is a detection system that uses radio waves to determine the distance (''ranging''), angle, and radial velocity of objects relative to the site. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, w ...
systems, beyond this it did not have enough accuracy to stay within its lethal radius. The use of X-ray based attacks in earlier generation BMD systems had led to work to counter these attacks. In the US, these were carried out by placing a warhead (or parts of it) in a cavern connected by a long tunnel to a second cavern where an active warhead was placed. Before firing, the entire site was pumped into a vacuum. When the active warhead fired, the X-rays traveled down the tunnel to hit the target warhead. To protect the target from the blast itself, huge metal doors slammed shut in the tunnel in the short time between the X-rays arriving and the blast wave behind it. Such tests had been carried out continuously since the 1970s.


Boost-phase attacks

A potential solution to the problem of MIRV is to attack the ICBMs during the
boost phase A ballistic missile goes through several distinct phases of flight that are common to almost all such designs. They are, in order: * boost phase when the main boost rocket or upper stages are firing; * post-boost phase when any last-minute changes t ...
before the warheads have separated. This destroys all the warheads with a single attack, rendering MIRV superfluous. Additionally, attacking during this phase allows the interceptors to track their targets using the large heat signature of the booster motor. These can be seen at distances on the order thousands of miles, given that they would be below the horizon for a ground-based sensor and thus require sensors being located in orbit. DARPA had considered this concept starting in the late 1950s, and by the early 1960s had settled on the Ballistic Missile Boost Intercept concept, Project BAMBI. BAMBI used small
heat-seeking missile Infrared homing is a passive weapon guidance system which uses the infrared (IR) light emission from a target to track and follow it seamlessly. Missiles which use infrared seeking are often referred to as "heat-seekers" since infrared is radi ...
s launched from orbiting platforms to attack Soviet ICBMs as they launched. In order to keep enough BAMBI interceptors within the range of the Soviet missiles while the interceptor's launch platforms continued to move in orbit, an enormous number of platforms and missiles would be required. The basic concept continued to be studied through the 1960s and 1970s. A serious problem was that the interceptor missiles had to be very fast to reach the ICBM before its motor stopped firing, which required a larger motor on the interceptor, meaning higher weight to launch into orbit. As the difficulties of this problem became clear, the concept evolved into the "ascent phase" attack, which used more sensitive seekers which allowed the attack to continue after the ICBM's motor had stopped firing and the warhead bus was still ascending. In all of these studies, the system would require an enormous amount of weight to be lifted into orbit, typically hundreds of millions of pounds, well beyond any reasonable projections of US capability. The US Air Force repeatedly studied these various plans and rejected them all as essentially impossible.


Excalibur's promise and development issues

The Excalibur concept appeared to represent an enormous leap in BMD capability. By focusing the output of a nuclear explosion's X-rays, the range and effective power of BMD were greatly enhanced. A single Excalibur could attack multiple targets across hundreds or even thousands of kilometers. Because the system was both small and relatively lightweight, the
Space Shuttle The Space Shuttle is a retired, partially reusable low Earth orbital spacecraft system operated from 1981 to 2011 by the U.S. National Aeronautics and Space Administration (NASA) as part of the Space Shuttle program. Its official program na ...
could carry multiple Excaliburs into orbit in a single sortie. Super Excalibur, a later design, would theoretically be able to shoot down the entire Soviet missile fleet singlehandedly. When first proposed, the plan was to place enough Excaliburs in orbit so at least one would be over the Soviet Union at all times. But it was soon noted that this allowed the Excalibur platforms to be directly attacked; in this situation, the Excalibur would either have to allow itself to absorb the attack or sacrifice itself to shoot down the attacker. In either case, the Excalibur platform would likely be destroyed, allowing a subsequent and larger attack to occur unhindered. This led Teller to suggest a "pop-up" mode where an Excalibur would be placed on
SLBM A submarine-launched ballistic missile (SLBM) is a ballistic missile capable of being launched from Ballistic missile submarine, submarines. Modern variants usually deliver multiple independently targetable reentry vehicles (MIRVs), each of whic ...
platforms on submarines patrolling off the Soviet coastline. When a launch was detected, the missiles would be launched upward and then fire as they left the atmosphere. This plan also suffered from several problems. Most notable was the issue of timing; the Soviet missiles would be firing for only a few minutes, during which time the US had to detect the launch, order a counter-launch, and then wait for the missiles to climb to altitude. For practical reasons, submarines could salvo their missiles only over a period of minutes, which meant each one could launch only perhaps one or two Excaliburs before Soviet missiles were already on their way. Additionally, the launch would reveal the location of the submarine, leaving it a "sitting duck". These issues led the
Office of Technology Assessment The Office of Technology Assessment (OTA) was an office of the United States Congress that operated from 1974 to 1995. OTA's purpose was to provide congressional members and committees with objective and authoritative analysis of the complex scien ...
to conclude that "the practicality of a global scheme involving pop-up X-ray lasers of this type is doubtful." Another challenge was geometric in nature. For missiles launched close to the submarines, the laser would be shining through only the uppermost atmosphere. For ICBMs launched from
Kazakhstan Kazakhstan, officially the Republic of Kazakhstan, is a transcontinental country located mainly in Central Asia and partly in Eastern Europe. It borders Russia to the north and west, China to the east, Kyrgyzstan to the southeast, Uzbeki ...
, some from the Arctic Ocean, the curvature of the Earth meant an Excalibur's laser beam would have a long path-length through the atmosphere. To obtain a shorter atmospheric path-length, Excalibur would have to climb much higher, during which time the target missile would be able to release its warheads. There was the possibility that a powerful enough laser could reach further into the atmosphere, perhaps as deep as altitude if it was bright enough. In this case, there would be so many X-ray photons all the air between the battle station and the target missiles would be completely ionized and there would still be enough X-rays left over to destroy the missile. This process, known as "bleaching", would require an extremely bright laser, more than ten billion times brighter than the original Excalibur system. Finally, another problem was aiming the lasing rods before firing. For maximum performance, the laser rods needed to be long and skinny, but this would make them less robust mechanically. Moving them to point at their targets would cause them to bend, and some time would be required to allow this deformation to disappear. Complicating the issue was that the rods needed to be as skinny as possible to focus the output, a concept known as ''geometric broadening'', but doing so caused the
diffraction limit The resolution of an optical imaging system a microscope, telescope, or camera can be limited by factors such as imperfections in the lenses or misalignment. However, there is a principal limit to the resolution of any optical system, due to t ...
to decrease, offsetting this improvement. Whether it was possible to meet the performance requirements within these competing limitations was never demonstrated.


Countermeasures

Excalibur worked during the boost phase and aimed at the booster itself. This meant the X-ray hardening techniques developed for warheads did not protect them. While many of the other SDI weapons had simple countermeasures based on the weapon's required ''dwell time'', like spinning the booster and polishing it mirror-bright, Excalibur's zero dwell time rendered these ineffective. Thus the primary way to defeat an Excalibur weapon is to use the atmosphere to block the progress of the beams. This can be accomplished using a missile that burns out while still in the atmosphere, thereby denying Excalibur the tracking system information needed for targeting. The Soviets conceived of a wide array of responses during the SDI era. In 1997 Russia deployed the
Topol-M The RT-2PM2 «Topol-M» (russian: РТ-2ПМ2 «Тополь-М», NATO reporting name: SS-27 "Sickle B", other designations: SS-27 Mod 1, RS-12M1, RS-12M2, formerly incorrectly RT-2UTTKh) is one of the most recent intercontinental ballistic missi ...
ICBM which utilized a higher-thrust engine burn following take-off, and flew a relatively flat ballistic trajectory, both characteristics intended to complicate space-based sensor acquisition and interception. The Topol fires its engine for only 150 seconds, about half the time of the SS-18, and has no bus, the warhead is released seconds after the engine stops. This makes it far more difficult to attack. In 1976, the organization now known as
NPO Energia PAO S. P. Korolev Rocket and Space Corporation Energia (russian: Ракетно-космическая корпорация «Энергия» им. С. П. Королёва, Raketno-kosmicheskaya korporatsiya "Energiya" im. S. P. Korolyov ...
began development of two space-based platforms not unlike the SDI concepts; ''Skif'' was armed with a CO2 laser while ''Kaskad'' used missiles. These were abandoned, but with the announcement of SDI they were repurposed as anti-satellite weapons, with Skif being used against low-orbit objects and Kaskad against higher altitude and geostationary targets. Some of these systems were tested in 1987 on the Polyus spacecraft. What was mounted on this spacecraft remains unclear, but either a prototype Skif-DF or a mockup was part of the system. According to interviews conducted years later, mounting the Skif laser on the Polyus was more for propaganda purposes than as an effective defense technology, as the phrase "space based laser" carried
political capital Political capital is the term used for an individual's ability to influence political decisions. This capital is built from what the opposition thinks of the politician, so radical politicians will lose capital. Political capital can be understoo ...
. One of the statements is that Polyus would be the basis for deployment of nuclear "mines" which might be fired from outside the range of the SDI components and reach the United States within six minutes.


In popular culture

A similar laser weapon, also named Excalibur, appears in the video games '' Ace Combat Zero: The Belkan War'' and ''
Ace Combat Infinity was a combat flight simulation video game developed by Project Aces and published by Bandai Namco Games is a Japanese multinational video game publisher headquartered in Minato-ku, Tokyo. Its international branches, Bandai Namco Entertain ...
''. In both of its appearances, Excalibur is presented as a gigantic, ground-based laser system that utilises mirror satellites to direct its laser beam; the device was originally designed to counter ICBMs, but was repurposed into an anti-aircraft weapon.


See also

*
Directed-energy weapon A directed-energy weapon (DEW) is a ranged weapon that damages its target with highly focused energy without a solid projectile, including lasers, microwaves, particle beams, and sound beams. Potential applications of this technology include w ...


Explanatory notes


References


Citations


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Further reading

* OTA-ISC-285. * * * *


External links

* {{featured article Anti-ballistic weapons Cold War weapons of the United States Directed-energy weapons Nuclear weapons program of the United States Strategic Defense Initiative