Livermore was at the forefront of designing new types of nuclear explosives with tailored output. For example, increasing the fraction of energy generated by nuclear fusion rather than fission produced a "low-fission" nuclear weapon, which would produce less fallout. In addition, in 1957, Laboratory scientists began to explore possible peaceful uses of nuclear explosives through Project Plowshare. Reduced amounts of residual radiation-fewer fission products from the explosion and less induced radioactivity of the ground-were necessary to make feasible peaceful applications such as earth moving and power production.
In 1956, President Eisenhower announced the testing of a 95% 'clean' (2-stage) fusion weapon, later identified to have been the 11 July 1956 Navajo test at Bikini Atoll during Operation Redwing. This weapon had a 4.5 megatons yield. Previous 'dirty' weapons had fission proportions of 50-77%, due to the use of uranium-238 as a 'pusher' around the lithium deuteride (secondary) stage. The fusion neutrons have energies of up to 14.1 MeV, well exceeding the 1.1 MeV 'fission threshold' for U-238. The 1956 'clean' tests used a lead pusher, while in 1958 a tungsten carbide pusher was employed.
The design approaches to reduce residual radiation in these early efforts proved critical to the Laboratory's development of warhead concepts that were deployed on the Spartan and Sprint antiballistic missile systems in the early 1970s. Development of the high-yield W71 warhead for Spartan, which was designed to intercept a cloud of reentry vehicles and decoys in space, was a major undertaking for Livermore.
By the end of 1964 interpretations of the United States 1962–1963 atmospheric nuclear test series began to raise the possibility of high yield explosions in space releasing a tremendous surge of hot X-rays that would flash over thousands of miles in the near-vacuum. The lethal radius of these X-rays increased by a factor of 100 according to one scientist and gave a new lift to the Nike Zeus concept. It appeared that the discarded Nike Zeus system was better than anyone had thought. These interpretations were widely accepted by mid-1965 and McNamara’s breathing spell which he had envisioned lasting until at least 1967, had suddenly disappeared.
The Army in 1964 requested no funds for deployment in the FY 1965 budget. As General William Dick, Chief of Army Research and Development said in testifying before Congress, there could be no real production decision made until at least 1966. This decision would have to wait on the MAR test results, since the MAR was the most critical component of the proposed Nike-X system, and these results would not be available until late 1964. Barring any unforeseen developments, a deployment decision was at least one or two years away. He of course was not aware of the hot X-ray kill mechanism at that time.
A Memorandum From the Joint Chiefs of Staff to Secretary of Defense McNamara, January 13, 1966, stated " While ACDA acknowledges the importance of a hot X-ray ABM system, the argument set forth by ACDA appears to be that the USSR does not possess the needed know-how to exploit this potential capability and that further restriction, at this time, could freeze the USSR and US ABM race. The NIE statement, “there is no evidence that [1-1/2 lines of source text not declassified] is not sufficient assurance in this case. The USSR has had the opportunity to discover this and other effects under the present treaty as well as in their 1961/1962 high-altitude, high-yield tests. These latter tests might also have uncovered effects we know nothing about. We cannot assume that the USSR knows less than the United States about these effects."
Project CANNIKIN was a nuclear test conducted on Amchitka Island, Alaska, at 11:00 a.m., Bering Standard Time, on November 6, 1971. CANNIKIN, a slightly less-than-five-megaton device, was the largest underground nuclear test conducted in the United States. CANNIKIN was conducted to proof test a warhead for the Spartan missile, a Safeguard Ballistic Missile Defense Program. The shock registered 7.0 on the Richter scale, the seismic unit of the time. Within two days after the explosion, a crater more than one mile wide and 40 feet deep formed.
Cannikin was a big event, and though almost every nuclear event represents some kind of technical breakthrough, Cannikin is outstanding both in the number of “firsts” and in size:
- First major project under the National Environmental Policy Act of 1969, which required the preparation of an “Official Environmental Impact Statement.”
- Largest mined shaft in the United States with a single elevator to 6,000 feet.
- Deepest 90-inch hole—6,150 feet.
- Longest diagnostic canister—264 feet.
- Largest off-continent diagnostic system—250 scopes with 100 percent data retrieval.
- Largest load lowered downhole—over 400 tons.
- Largest emplacement drill rig—1,000 ton mast.
- First operational field computer system.
- First successful downhole alignment with a laser beam.
- First use of over 100 miles of downhole cables.
- Largest cavity (52 foot diameter) mined through a mile-long shaft.
In addition, Cannikin required the use of the largest number of recording trailers. Shock mounting the trailers was a challenge because the trailers and interior instrumentation, located about 2,000 feet from ground zero, had to be able to withstand a ground upheaval of 15 feet at shot time.
The morning before the Cannikin event at Amchitka Island, Alaska, the test site was subjected to rain and wind gusts up to 124 miles per hour. The test crew and visiting dignitaries, including Atomic Energy Commission Chairman James Schlesinger and his family, anxiously waited. Meanwhile, the Supreme Court ruled by a 4- 3 margin that the test could take place. On November 6, 1971, at 6: 30 a. m. in Amchitka, the go-ahead came from the White House on a telephone hotline. Cannikin was successfully detonated at 11 a. m., and the nearly 5- megaton blast generated the ground motion of a 7.0 Richter- scale- magnitude earthquake.
Cannikin was a massive undertaking involving hundreds of Laboratory employees and nearly five years of effort. Test operations overcame a myriad logistics hurdles, and experimenters achieved many technical firsts. Two years of drilling produced a record- breaking emplacement hole that was 6,150 feet deep and 90 inches in diameter with a 52- foot- wide cavity mined at its bottom. The diagnostics canister was 264 feet long, and altogether 400 tons of cables and equipment were lowered downhole. Cannikin was the first test in which a laser successfully aligned diagnostics downhole and a computer system assisted field operations. A record- setting number of recording trailers, 2,000 feet from ground zero and shock mounted to withstand a ground upheaval of 15 feet at shot time, were instrumented with 250 oscilloscopes. One hundred percent of the test data was successfully retrieved.
The experiment tested the design of the warhead for Spartan, the interceptor used in the upper tier of the U. S. Safeguard Anti- Ballistic Missile (ABM) system. Spartan missiles were to engage clouds of reentry vehicles and decoys above the atmosphere and destroy incoming warheads with a burst of high- energy x rays. The Laboratory stepped up to the difficult challenge of designing the appropriate warhead. The Spartan warhead had high yield, produced copious amounts of x rays, and minimized fission output and debris to prevent blackout of ABM radar systems. Livermore also developed and first tested the warhead technology for the second- tier interceptor, the Sprint missile. Subsequently, Los Alamos was assigned responsibility to develop the nuclear warhead for Sprint.
The successful Spartan antiballistic missile test at Amchitka in the Aleutian Islands got Roger Batzel's tenure as director of Livermore started with a bang. The test also produced a story that epitomizes his supportive, hands-off managerial style. Phil Coyle, who was later deputy director of the Laboratory, was in charge of the test and asked Batzel if he should send in daily or weekly reports while preparations for the test were under way. Batzel replied that they wouldn't be necessary. "How about monthly reports?" asked Coyle, unable to believe what he was hearing. "No," Roger replied. "You don't need to submit any reports. Just know that we want you to succeed, and we are here to help."
The Safeguard ABM system was a scaled-down version of the Sentinel system for defense of U. S. cities. Rapid evolution of offensive missile technologies made national defense impractical, and in 1972, the United States and the Soviet Union signed the ABM Treaty. However, protection against ballistic missile attack remained a goal and technological challenge for Laboratory researchers and was pursued with renewed vigor after President Reagan launched the Strategic Defense Initiative. Nuclear directed- energy weapons were pursued at Livermore, including experimental demonstration of x- ray lasing at the Nevada Test Site.
For the Livermore-designed weapon systems being retired the Lab has a continuing active responsibility to ensure safe and timely dismantlement and disposition of excess materials. Dismantlement of the W68 SLBM warheads and the W71 ABM warheads was completed in 1995.