Silencing the Bomb: One Scientist’s Quest to Halt Nuclear Testing

FROM THE EARLY NEGOTIATIONS TO HALT NUCLEAR TESTING TO THE LIMITED TEST BAN TREATY OF 1963

I highlight here some of the proposals, negotiations, and problems in working toward either a limited (LTBT) or a full comprehensive nuclear test ban (CTBT) during the administrations of Dwight D. Eisenhower and John F. Kennedy.

Following a call by India’s Prime Minister Nehru in 1954 for a pause in nuclear testing, several other countries presented proposals for a halt in testing. Formal negotiations toward a test ban began in the second half of the 1950s and continued into the early 1960s.

PROS AND CONS OF BANNING NUCLEAR TESTS

Debate has raged for more than sixty years over whether a Comprehensive Nuclear Test Ban Treaty (CTBT) is in the interest of the United States. I touch here briefly on some of the main reasons a CTBT has been either proposed or opposed.

It should be remembered that a CTBT involves a ban on the testing of nuclear weapons, not a ban on their delivery systems such as aircraft and missiles. It does not prohibit the manufacture of additional weapons that have already been tested. While a CTBT is an important step, it is but one component of an overall effort to control nuclear arms. A CTBT may help to promote other arms control initiatives and agreements.

Many of the arguments for and against a CTBT (see Table 3.1) have been enunciated for decades. Some are new with the 1996 treaty. It is important to note that verification capabilities have increased, especially in the past twenty years.

TABLE 3.1 Pros and Cons of Banning Nuclear Tests

PRO	CON
1. The U.S. lead in nuclear weapons will diminish without a CTBT.	Others will cheat and erode the U.S. lead. National security is best enhanced by continued testing of new weapons.
2. The treaty will slow or halt the nuclear arms race (stop continued development of weapons by nuclear powers; stop new states from testing and acquiring nuclear arms).	This is wishful thinking.
3. The treaty is verifiable down to explosions of very tiny yields, which are not of military significance.	Even an explosion between zero and a few hundred tons’ yield gives an advantage to others. Determined cheaters will test important weapons evasively below verification limits.
4. The treaty is for zero nuclear yield.	The lower yield limit is vague; it should be a low yield threshold treaty.
5. Russia and China are unlikely to be able to deploy a new long-range nuclear weapon without several multi-kiloton tests, which would be detectable even with evasive testing.	Tactical and other weapons with yields below one kiloton are important (x-ray laser, electromagnetic pulse warhead).
6. The Stockpile Stewardship program is more effective than originally thought.	The program is not good enough without the ability to test existing and new weapons.
7. U.S. classified verification capabilities are better than the International Monitoring System (IMS). The United States makes its own determinants for a suspicious event.	The IMS is not good enough. The United States will surrender assessment of an event as being nuclear to the IMS and the UN.
8. The United States can pursue a few arms control agreements simultaneously.	Strategic arms limitations are more important than test bans.
9. Tests of thermonuclear weapons are unlikely to be concealable even with evasive testing. This would end development of advanced types of weapons.	Weapons labs need testing to retain top scientists.
10. If problems occur with existing weapons, the United States can withdraw from the treaty within six months.	To prevent deterioration of weapons, nuclear testing is necessary.
11. On-site inspections are possible once the treaty enters into force. The UN General Assembly could bring it into force without rogue states once the United States and China ratify.	Entry into force will never occur because forty-four countries must ratify the CTBT.
12. Components of nuclear explosives can be remanufactured and old components replaced.	Some components of nuclear explosives cannot be remanufactured.
13. It is illusory to believe that amendments to the treaty, such as making it of limited duration, can be negotiated with other signatories. The U.S. Senate should enact U.S. safeguards.	The treaty should be amended to make it of limited duration.
14. The treaty helps to establish the norm that the only value of nuclear weapons is for deterring their use by others.	Other countries and terrorists may not accept this view. Rogue nations will test. Nuclear weapons are needed to attack chemical and biological weapons.
15. U.S policy is that it does not need new nuclear weapons.	The United States should develop and test new nuclear weapons; requirements change.
16. The treaty will strengthen international peace and security. International support for the treaty is very strong.	This is a false hope.
17. U.S., Russian, and Chinese weapons are already one-point safe; hence, they do not need tiny nuclear warheads.	To improve safety, add insensitive high explosives to submarine warheads.

In addition to the statements listed in Table 3.1, several domestic arguments have been made for U.S. ratification of a complete test ban.

1. A CTBT is favored by a vast majority of Americans. Polls indicate that few people in the United States know that the Senate defeated the CTBT in 1999.

2. The United States would miss an historic opportunity to make the world safer for future generations.

3. Failure to ratify the CTBT would weaken the effectiveness of the Nonproliferation Treaty (NPT). Some nations may withdraw. (Thus far, however, only North Korea has withdrawn from the NPT.)

4. Failure to ratify would undercut the status of America as a world leader. Global standards do matter.

5. U.S. ratification may dissuade others such as India and Pakistan from conducting more tests. (They have not tested since 1998. Only North Korea has tested nuclear weapons in the twenty-first century.)

U.S. AND SOVIET PROPOSALS TO HALT TESTING

In July 1955 and again in 1956, Premier Nikolai Bulganin of the USSR proposed an end to nuclear testing. His plan, however, did not include verification. Understandably, the United States argued for verification of arms control agreements, especially those related to nuclear weapons. In 1955 the declared aim of the United States was to seek a comprehensive disarmament agreement that included verification.

The U.S. position on halting or limiting nuclear testing underwent several changes during the Eisenhower administration, which ran from 1953 through early 1961. In 1956 Adlai Stevenson, the Democratic nominee for president, suggested the United States might stop testing as a first step toward an agreement with the USSR. He reasoned that the United States could verify a ban on high-yield testing, ending the worst dangers of radioactive fallout.

The radioactive isotope strontium 90 produced by testing in the atmosphere was detected in human bones and teeth worldwide in the 1950s. Since the chemistry of strontium is similar to that of calcium, humans adsorb radioactive strontium (Sr 90) as if it were calcium in dairy and other foods. Sr 90 has a half-life of about twenty-eight years. (A half-life is the time it takes for a radioactive isotope to decay to half its original concentration.) Hence, it takes two hundred years for Sr 90 to decay to 1 percent of its initial value. In 1959 Lamont geochemist Larry Kulp and his colleagues, who made many of the measurements on human bones, published their results in the journal Science, drawing public and governmental attention to the issue of fallout from atmospheric testing.

By 1957 a number of scientists, public figures, and various organizations demanded an end to nuclear testing. Chemist and Nobel Laureate Linus Pauling of Cal Tech circulated a petition calling for a test ban; nine thousand scientists in forty-three countries signed it. In the United States, SANE, the Committee for a Sane Nuclear Policy, placed ads in major newspapers citing the perils of nuclear war. Thousands of letters protesting continued nuclear testing were sent to President Eisenhower. Many nongovernmental organizations in the United States and the UK who protested against continued testing became active at that time.

In May 1957, the United States and the Soviet Union exchanged proposals for a test ban and cutoffs in the production of materials for nuclear weapons but failed to reach an agreement. In March 1958, the Soviet Union announced a unilateral suspension of testing after completing its latest series of many atmospheric nuclear explosions. It urged the United States to do likewise. It came just as the United States was about to start a major series of weapons tests in the Pacific and at the Nevada Test Site. On April 8, 1958, President Eisenhower proposed a technical conference to explore the verification of a test ban.

Many people are not aware that Eisenhower and his administration were very involved in several proposals and negotiations to ban or limit nuclear testing. President Kennedy is often cited for achieving, as he did in 1963, the Treaty Banning Nuclear Weapons Tests in the Atmosphere, in Outer Space, and Under Water, often called the Limited Test Ban Treaty (LTBT). It did not cover underground testing. Nevertheless, much work on testing limitations and verification occurred during Eisenhower’s presidency.

EARLY ATTEMPTS TO IDENTIFY NUCLEAR TESTS

The first Soviet test in 1949 resulted in an expansion of a variety of monitoring technologies by the United States, Great Britain, and Canada. These included seismic stations, infrasound detectors for low-frequency acoustic waves in the atmosphere, hydrophones for detecting explosions in the oceans, and instruments for detecting explosions in the upper atmosphere and space.

In July and August 1958, a Conference of Experts to Study the Methods of Detecting Violations of a Possible Agreement on the Suspension of Nuclear Tests was held in Geneva. It was often called the Conference of Experts. Western delegations were from the United States, the United Kingdom, Canada, and France; eastern delegates were from the USSR, Czechoslovakia, Romania, and Poland. James Fisk, a senior scientist and administrator at Bell Labs, headed the U.S. delegation; William Penny, the British. Supporting the U.S. delegation were a number of advisers, including five seismologists and a number of scientists familiar with nuclear weapons programs. Yevgeni Fedorov, a Soviet geophysicist, headed the eastern delegation. Unlike the U.S. delegation, the USSR delegation included a senior diplomat. Many criticized Eisenhower for not including a senior diplomat in the U.S. delegation.

Their agenda was unclear. In his 2009 book Detecting the Bomb: The Role of Seismology in the Cold War, U.S. seismologist Carl Romney wrote, “Fedorov promptly raised an essentially political issue by proposing a statement of objectives that amounted to a prior commitment to a test ban.” Romney also stated, “Fisk countered that the Conference should confine its work to defining methods of detection, analyzing their capabilities and limitations, and let Governments decide how to use the information.”

In advocating a treaty first with verification later, the Soviet Union stated that monitoring posts on its territory staffed by foreign citizens would be an excuse for espionage. The United States wanted strong verification measures such as monitoring stations in the USSR. The Soviet delegation received new instructions on many of the verification proposals enumerated by Fisk. Informal meetings on each of these topics were largely technical and constructive, whereas formal meetings of the entire delegations were more politically charged.

A final report completed in August 1958 contained agreed-upon conclusions on verifiability, the establishment of a global network of 180 monitoring (control) stations, and the need for on-site inspections. Nevertheless, identifying underground explosions and distinguishing their signals from those of earthquakes were the most contentious issues, as they remained for many decades. I think that these issues, in fact, were resolved by 1970.

Much data existed by 1958 on monitoring explosions in the atmosphere but not much on underground tests. Detection of acoustic waves from explosions in the oceans was known to be considerably easier than identification of underground nuclear explosions. In 1955 the United States detonated a 30-kiloton underwater device called Wigwam in the eastern Pacific. Sensors detected this and the Baker underwater test of 1946 at large distances. The Soviet Union conducted two underwater nuclear explosions of 6 and 10 kilotons near its Arctic islands of Novaya Zemlya. Romney stated that both underwater shots were well recorded by stations of the U.S. Atomic Energy Detection System (AEDS). Those results, the locations of stations, and the capabilities of AEDS at the time, however, were classified and remained so for decades. While Romney had access to them, most other scientists did not.

The experts from the United States and the USSR agreed that earthquakes under the oceans, which account for about half of the world’s earthquakes, could be considered as identified if they did not produce large acoustic signals (sound waves) in the oceans. An explosion in the water column is much more efficient at generating those waves than an earthquake within the oceanic crust.

Many earthquakes deeper than about 30 to 45 miles (50 to 75 km) could be identified using the seismic wave pP, which arrives soon after the P wave and is reflected from the surface of the Earth near the earthquake source (figure 3.1). These included deeper earthquakes beneath the Kuril-Kamchatka region, the most active area of the USSR, and those beneath the Hindu Kush and Pamir mountains of Central Asia. Shallower earthquakes are often difficult to identify using pP waves because they arrive very soon after P waves.

FIGURE 3.1

Interior of the Earth. Lines with arrows indicate paths of seismic waves between a source, such as an earthquake, and a recording station. The epicenter is the point on Earth’s surface directly above the hypocenter of an event.

Source: Sykes and Evernden, 1982.

When the Conference of Experts met in August 1958, all nuclear tests had been conducted either in the atmosphere or underwater with the exception of a single very small U.S. underground explosion code-named Rainier. It was detonated in a volcanic rock called tuff during September 1957 at the Nevada Test Site, which had opened in 1951. Its yield of 1.7 kilotons was about ten times smaller than the nuclear explosions of 1945 and ten thousand times smaller than the largest hydrogen bombs tested as of 1958.

U.S. government scientists twice reduced their estimate of Rainier’s seismic magnitude because stations at different distances gave different results. Many people contested the idea that the 1957 test was difficult to detect seismically and that its signals were hard to distinguish from those of earthquakes. The USSR did not detonate an underground test until October 1961. It was of similar size to Rainier and was likely detonated at the Eastern Kazakhstan test site in much harder rock than Rainier. It was well detected outside the USSR.

Throughout 1958, both the Soviets and Americans set off many nuclear explosions. The Soviet Union conducted nuclear tests in the atmosphere from February until November 3, 1958. Several were probably in the megaton range. The United States conducted a series of nuclear explosions in the Pacific, called Operation Hardtack I, starting in April 1958. It consisted of atmospheric explosions with yields ranging from a few kilotons to about 10 megatons (10,000 kt) and two underwater shots. Testing ended in August 1958 with two high-altitude nuclear explosions with yields of 3.8 megatons near Johnston Island in the Pacific, which produced radio blackouts and observable effects in the Pacific similar to northern lights.

The United States conducted additional nuclear explosions in the atmosphere at the Nevada Test Site in September and October 1958 as part of Operation Hardtack II, which also included underground tests of Logan at 5 kilotons, Blanca with a yield of 22 kilotons, and several explosions smaller than one kiloton.

Upon completion of the Experts’ Report at the end of their conference on August 22, 1958, President Eisenhower proposed a one-year testing moratorium on all testing if the Soviet Union also refrained. This moratorium would be extended on a year-by-year basis if the control system recommended by the Experts could be installed and progress made on arms control agreements. While a treaty was being negotiated, both the Soviet Union and the United States continued to conduct nuclear tests into the fall of 1958.

Treaty negotiations, called the Conference on the Discontinuance of Nuclear Tests, began in Geneva on October 31, 1958, a day after the Blanca explosion by the United States. Parties to the conference consisted of the three nuclear states at the time—the United States, the United Kingdom, and the Soviet Union.

The USSR’s second underground nuclear test did not occur until February 1962. It took place at its Eastern Kazakhstan test site with a yield comparable to that of the U.S. test Blanca. Because most of Russia consists of areas of old geologic units that favor very good propagation of seismic waves, the United States overestimated the yields of underground nuclear explosions at the two main Soviet test sites, including those of 1961 and 1962, by a factor of about three times and continued to do so for decades.

The United States calibrated unknown Soviet yields from their measured seismic magnitudes using measured yields and magnitudes of underground nuclear explosions in Nevada and southern Algeria. This turned out to be a big mistake that led to the large overestimations of Soviet yields. The Soviet Union did know, however, that seismic waves propagated efficiently in various parts of their country from its earlier large chemical explosions.

U.S. REASSESSMENT OF DIFFICULTIES WITH VERIFICATION IN 1959

A key factor in the U.S. reluctance to negotiate a treaty was that U.S. Department of Defense officials and others were not convinced about the reliability of identifying nuclear explosions of moderate and small size. They argued that seismic signals from underground explosions based on 1958 data were both smaller and harder to distinguish from the signals of earthquakes of comparable size than the forecasts of the Experts in August 1958.

After reviews within the U.S. government, these new findings from underground explosions in 1958 were tabled as negotiations resumed in Geneva in January 1959. The White House issued a public statement about the new findings and their implications. Because some of the best seismic data and information for the underground explosions in Nevada in 1958 were classified, it was difficult, however, for most seismologists to form independent judgments about the identification of small nuclear explosions.

The relevance of the new U.S. data on underground explosions was strongly challenged by Soviet geophysicists Y. Riznichenko and Leonid Brekhovskikh in an article in Pravda on January 20, 1959. The Soviet ambassador to the conference stated that the Experts’ report of the previous summer should be the sole technical basis for the negotiations. The U.S. ambassador to the Geneva talks insisted that the new data must be considered. He also proposed a technical meeting to discuss detection of high-altitude nuclear explosions.

The Eisenhower administration formed a Panel on Seismic Improvement, consisting of U.S. seismologists and other experts, that was chaired by Lloyd Berkner, president of Associated Universities. Known as the Berkner Panel, its initial assignment was to ascertain if improvements could be made to the monitoring stations proposed by the Experts so that the number of problem seismic events per year being considered would not have to be increased. Their main task was to resolve the difficulties in identifying underground explosions and distinguishing their seismic signals from those of earthquakes.

The findings of the Berkner Panel were introduced at the Geneva conference in June 1959. Their recommended improvements consisted of greater numbers of seismic sensors at each control post, the use of seismic surface waves for discriminating earthquakes from explosions, and the placing of unmanned instruments, so-called black boxes, in earthquake-prone areas of the USSR and the United States. The black boxes would be designed to be tamper proof.

SEISMIC MAGNITUDES USED TO DESCRIBE THE SIZES OF EARTHQUAKES AND UNDERGROUND NUCLEAR EXPLOSIONS

It is necessary to have a simple way to describe the sizes of earthquakes. Seismologists use many different magnitude scales to do this. They all involve measuring the amplitude, or size, of a particular seismic wave, taking the logarithm of its amplitude, and making a correction for the distance between the source and a seismic station. Logarithms are used because the sizes of seismic waves vary over a huge range. Because magnitude scales are logarithmic, magnitude increases one unit when amplitude increases ten times. Hence, an earthquake of magnitude 6 is ten times larger in amplitude than an event of magnitude 5. In 1935, Charles Richter at Cal Tech devised the original magnitude scale, called M_L or Richter magnitude, for local earthquakes in southern California. The magnitudes listed in table 3.2 are not those proposed by Richter but ones appropriate for events at large distances.

TABLE 3.2 Earthquake Magnitudes

m_b	Determined from the amplitudes of short-period seismic P waves, usually at distances greater than about 1250 miles (2000 km)
Ms	Determined from the amplitudes of long-period seismic surface waves
m_bLg	Determined from the amplitudes of seismic waves at regional distances (less than 1250 miles or 2000 km) within continents
Mw	Determined from very long-period (low-frequency) seismic waves; called moment magnitude

In describing underground nuclear explosions and earthquakes, the United States advocated the use of the seismic magnitude m_b, which could be measured from P-waves on seismograms, whereas explosive energy or yield could not be measured directly. Energy is a physical quantity, whereas seismic magnitude is not.

FURTHER PROPOSALS BY THE EISENHOWER ADMINISTRATION

In the 1959 negotiations, the United States also emphasized that methods could be used to mask or reduce the sizes of seismic waves from nuclear tests. Disagreements with the Soviet Union about evasion and the determination of seismic magnitudes were a complete nonstarter for the remainder of the talks with the USSR through 1963.

In April 1959, Eisenhower proposed a phased approach to achieving a comprehensive nuclear test ban. He stated that Soviet proposals did not provide for effective control (i.e., verification) and recommended starting with a ban on nuclear tests in the atmosphere. The proposal was endorsed by British prime minister Macmillan and, with some further modifications, was accepted by Soviet premier Nikita Khrushchev. This made it likely that a test ban treaty could be signed at the Paris summit that both President Eisenhower and Premier Khrushchev agreed to attend in May 1960.

The downing of an American U-2 spy plane over the Soviet Union on May 1, however, led to an atmosphere of hostility that cut short the Paris summit and the chance for a test ban during the remainder of Eisenhower’s presidency. Glen Seaborg, the discoverer of plutonium for which he won the Noble Prize, a chairman of the Atomic Energy Commission, and an adviser to ten U.S. presidents, was known for daily entries in his diary. In his 1981 book he wrote, “President Eisenhower, alarmed by the increased tensions, was reported to have decided to order the resumption of testing if Richard Nixon won the election” [in November 1960]. After Kennedy’s victory, he advised the president-elect “to resume testing without delay.”

The Geneva conference recessed in December 1959 with each of the three parties submitting annexes about the verification of underground testing. Because the Soviet annex differed considerably from those of the United States and Britain, a considerable impasse existed. Negotiations resumed in January 1960 with proposals for annual quotas on the number of on-site inspections and a threshold ban on underground testing, which was to prohibit large underground tests. The United States proposed a seismic magnitude threshold of 4.75, about 15 to 20 kilotons. This conversion of magnitude to yield was based solely on a few underground tests in 1957 and 1958 in Nevada in tuff, a soft rock. A magnitude m_b of 4.75 corresponds to smaller nuclear explosions at the two main Soviet test sites.

The USSR declared a moratorium on nuclear testing after completing a large series of nuclear tests in November 1958. Likewise, the United States followed its own self-declared moratorium after completing the Hardtack tests in October 1958. Neither country is known to have tested nuclear explosions for nearly three years. One exception is that the United States conducted explosions in secret with tiny nuclear yields equivalent to the explosive power of only several pounds (kilograms) of TNT. Called hydronuclear, these explosions confirmed that U.S. weapons were “one-point safe”—that is, a sudden shock at one point on their surface would not lead to a large inadvertent nuclear explosion.

In the meantime, France conducted its first nuclear test in Algeria in February 1960. The Soviet Union stated that the United States could obtain information about the development of nuclear weapons from the French even if the United States was observing a moratorium. This provided an excuse when the USSR resumed nuclear testing in September 1961.

SOVIET SERIES OF LARGE NUCLEAR TESTS IN 1961 AND 1962

The Soviet Union suddenly ended its self-declared moratorium on testing, detonating a huge series of nuclear explosions starting on September 1, 1961. The previous day, it announced that it would resume testing. It came at the height of the Berlin crisis, when the Soviet Union attempted to block western access to that city and the United States flew in supplies. Several tests were in the megaton range, and about six were 10 to 30 megatons. Numerous Soviet tests, most of them in the atmosphere, continued until December 25, 1962.

The Russians also detonated the largest nuclear explosion ever conducted at their Arctic test site near the islands of Novaya Zemlya on October 30, 1961. Premier Khrushchev announced it ahead of time. The explosion occurred in the atmosphere with a yield of about 42 to 50 megatons, more than three thousand times the power of the Hiroshima bomb of 1945 (figure 3.2). It is often called either “the Tsar bomb” or “Big Ivan.”

FIGURE 3.2

Yields of key nuclear explosions detonated by the Soviet Union and the United States in the atmosphere and underground. Size or yield of nuclear explosions is in kilotons (kt).

Unpublished figure by the author.

Its detonation certainly scared the United States government. Soviet nuclear scientists later said it was never weaponized; it was one of a kind and was not mass-produced for delivery by airplanes or missiles. In fact, the development of new nuclear weapons in the mid-1960s to the mid-1970s involved yields smaller than several megatons for single-warhead missiles and yields smaller than a megaton for missiles with multiple warheads.

The Soviet resumption of nuclear testing caught the United States by surprise. The many tests must have been planned well in advance. Some people in the United States accused the Soviet Union of cheating by preparing to test while negotiations were in progress in Geneva. Both sides, however, were following self-declared moratoria at the time, not treaties, protocols, or other agreements of indefinite duration. Nevertheless, it contributed to a U.S. view that the Russians could not be trusted.

President Kennedy ordered the resumption of nuclear testing by the United States on September 5, 1961; explosions commenced in Nevada ten days later. The United States and the United Kingdom started testing at Christmas Island in the Pacific in April 1962 and then at Johnston Island.

In 1957 the Soviet Union used a large missile to launch a satellite called Sputnik. Its success was followed by the failure of a U.S. rocket launched from the ground that was to deploy a satellite. This led to apprehension in the United States that the USSR was ahead in the development of intercontinental ballistic missiles (ICBMs) that could carry nuclear weapons.

President Eisenhower, however, was well aware of the secret development of military ICBMs by the United States, but he did not publicly divulge its existence. Kennedy ran for election as president in 1960 on the claim that a “missile gap” favored the Soviet Union. The apparent gap disappeared soon after Kennedy became president. The United States observed via early satellite imagery that the Soviet Union possessed fewer ICBMs than was claimed. The United States was, in fact, ahead in deployed ICBMs.

THE CUBAN MISSILE CRISIS

The world came the closest it has come thus far to nuclear war during the Cuban Missile Crisis of October 1962. An American U-2 spy plane secretly photographed nuclear missile sites being built in Cuba by the Soviet Union. Decades later senior Soviet military officials revealed that their commanders in Cuba had been authorized to launch medium-range SS-4 ballistic missiles at the United States if the United States attacked the Russian sites in Cuba. The SS-4’s carried nuclear weapons. Khrushchev undertook the installation of missiles in Cuba, apparently regarding Kennedy as young and inexperienced.

Several high-ranking military officials advised Kennedy to invade Cuba, but fortunately he refrained. Instead, he instituted a U.S. naval blockade to prevent the Soviets from bringing more military equipment and supplies into Cuba. Both Kennedy and Khrushchev recognized the devastating possibility of a nuclear war and publicly agreed to a deal. The Soviets withdrew their nuclear weapons and missiles from Cuba. Under an unannounced part of the agreement, which remained secret for more than twenty-five years, the United States withdrew old Jupiter missiles from Turkey.

A few months after the crisis, a personal insight came from my father, who was in charge of security at the Washington Air Traffic Control Center. He was responsible for keeping military aircraft separated from civilian flights in their broad area of traffic control. He mentioned to me the huge numbers of military flights over the southeastern United States during the Cuban crisis and said, “You don’t know how close we came to war.”

THE LIMITED NUCLEAR TEST BAN TREATY OF 1963

The Cuban Missile Crisis and the fear of nuclear war became a turning point in test ban negotiations. Khrushchev wrote Kennedy in December 1962, “The time has come now to put an end once and for all time to nuclear tests.” He offered three on-site inspections (OSIs) per year. The United States informed Soviet officials in February 1963 that it was willing to reduce its proposed annual quota of OSIs to seven. Many people assumed that a compromise between three and seven OSIs would be easy to achieve and a test ban would follow. Nevertheless, different views in the United States about evasive testing, the effectiveness of monitoring, and the use of seismic magnitudes continued to impede an agreement that would include underground tests.

A conciliatory speech by Kennedy at American University in June 1963 and Khrushchev’s welcoming of it led to an agreement among the United States, the United Kingdom, and the USSR to hold test ban talks in Moscow. Former ambassador to the Soviet Union W. Averell Harriman led the U.S. delegation. A full CTBT was the U.S. objective. If that was not possible, Harriman was to seek a limited treaty banning nuclear tests in the atmosphere, underwater, and in space. On the opening day of the negotiations in July 1963, the USSR submitted a draft treaty that included those environments but not underground testing. The Soviet Union would accept unmanned “black boxes” on its territory but not on-site inspections. OSIs were considered essential by the United States.

Discussion of a full test ban did not extend beyond the first day of the negotiations. The three principals very quickly agreed to a limited test ban treaty (LTBT), which was signed on August 5, 1963. It prohibited any explosion that “causes radioactive debris to be present outside the territorial limits of the State under whose jurisdiction or control such explosion is conducted.” The treaty was opened to signature by all states three days later and entered into force on October 10, 1963.