The Other Frigate Bird
Seen through the periscope of USS Carbonero (SS-337), submerged 25 miles from the aim point, this graphic illustration shows Frigate Bird’s mushroom-shaped cloud boiling skyward from its original burst altitude of 11,000 feet. The range clock at the upper right indicates 1433, which was the local time at the launching point. (Local time at the aim point was one hour earlier.)

The dictionary describes the frigate bird – sometimes called the man’o’war bird – as “any of several rapacious totipalmate sea birds of the genus Fregata, noted for their powers of flight.” Indeed with a wingspan up to 90 inches and the male’s ability to inflate his bright-red pouch during courtship in a spectacular display, the frigate bird is a unique animal. Equally unique was a nuclear test of that same name conducted near Christmas Island in the Pacific during May 1962. Even now, the Frigate Bird test remains the only end-to-end system test of a strategic nuclear missile – from launch to detonation – ever carried out by either side during the Cold War. And the Frigate Bird Test was a Submarine Force demonstration, featuring a Polaris A-1 missile fired from USS Ethan Allan (SSBN-608).

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Launched at Electric Boat in November 1960, USS Ethan Allen (SSBN-608) was the sixth of the original “41 for Freedom” SSBNs. She had been in commission for less than a year when she was selected as the firing ship for Frigate Bird. Ethan Allen was eventually decommissioned in 1983 after a brief twilight career as an SSN.


USS Ethan Allen (SSBN-608)

Launched at Electric Boat on 22 November 1960 as the sixth of the original “41 for Freedom” strategic ballistic missile submarines, USS Ethan Allen (SSBN-608) was commissioned in August 1961 and had only just completed her Post-Shakedown Availability when she was selected to be the firing ship for Frigate Bird. After returning to the Atlantic from Operation Dominic, Ethan Allen commenced her first deterrent patrol in late June 1962 and eventually completed 57 deterrent patrols before conversion to an SSN in September 1980. The ship was decommissioned in March 1983 and spent her final years at the Puget Sound Naval Shipyard, where her dismantling and nuclear recycling were completed in July 1999.

Because the first five U.S. SSBNs were actually built as a variant of the earlier USS Skipjack (SSN-585) configuration, Ethan Allen was the first submarine specifically designed for the strategic SSBN role. She displaced 6,900 tons surfaced and 7,900 tons submerged on a length of 410 feet, and in 16 vertical-launch missile tubes, she carried the Polaris A-1, A-2, and A-3 strategic ballistic missiles at various stages of her career. The ship was powered by an S5W pressurized-water reactor for an underwater speed of greater than 25 knots. Her complement was 12 officers and 128 enlisted men.

The First Nuclear Testing Moratorium

Trinity, the world’s first nuclear explosion, took place in the New Mexico desert early on the morning of 16 July 1945, during the final months of World War II. Within another month, the two atomic bombs dropped on Hiroshima and Nagasaki had brought that conflict to a merciful conclusion, only to usher in the beginnings of a Cold War that eventually pitted the Soviet and western blocs against each other in a near-global confrontation. With President Truman’s approval, the first peacetime nuclear weapon tests – Operation Crossroads – were mounted at Bikini Atoll in the Marshall Islands in July 1946, primarily to measure atomic weapon effects on warships. The second of these two explosions – code-named Baker – produced one of the most memorable images of the towering mushroom-shaped cloud that became an icon of the nuclear age.

Three more nuclear tests followed at Enewetak Atoll in 1948, and by the time the Soviet Union detonated its first atomic bomb in August 1949, the United States had already exploded eight “devices,” including Trinity and the Hiroshima and Nagasaki bombs. As the Cold War deepened, the resulting nuclear competition accelerated rapidly and soon led to the development and testing of thermo-nuclear weapons (“hydrogen bombs”), first by the United States in October 1952, and then by the Soviets somewhat less than three years later. By mid-1958, the United States had conducted nearly 200 weapons tests, mostly at Enewetak and the recently established Nevada Test Site northwest of Las Vegas. Meanwhile, the Russians had accomplished at least 75 nuclear detonations.

On 22 August 1958, President Eisenhower – alarmed by the accelerating arms race and the possible environmental dangers of atmospheric testing – announced that if agreement were reached to begin meaningful negotiations on a nuclear test ban, the United States would observe a renewable unilateral moratorium on nuclear testing for at least a year. Soviet premier Nikita Khrushchev acquiesced, negotiations were duly initiated, and after one final test by each nation – within three days of each other two months later – no tests were conducted by either country for nearly three years.

On 1 September 1961, however, the Soviet Union “broke out” of the moratorium and scheduled 45 atomic weapon tests in 65 days, including the largest-ever nuclear explosion before or since – a 63-megaton hydrogen bomb. It was clear that the Soviet test series had resulted from long and careful
preparation during a time when many of the corresponding U.S. test capabilities had been allowed to atrophy. Thus, on 5 September 1961, then-President John F. Kennedy reluctantly announced that U.S. nuclear weapons testing would have to resume, and 10 days later, the first of a new series of underground tests was implemented at the Nevada Test Site.

Even before the end of the moratorium, the U.S. atomic weapons community had begun to agitate for the resumption of atmospheric testing, and the Navy had already started contingency planning for systems tests of both the submarine-launched Polaris strategic missile and the ASROC surface-launched anti- submarine weapon, which in one variant carried a nuclear depth bomb. Additionally, the Air Force was anxious to conduct a similar systems test of an Atlas intercontinental ballistic missile from Vandenberg Air Force Base in California. In early November 1961, President Kennedy directed the Atomic Energy Commission and the Department of Defense to begin preparations for atmospheric testing, but it wasn’t until early March 1962 that he formally announced his approval for a new series of open-air tests to commence late the following month.

The new test series, Operation Dominic, comprised 31 nuclear tests between late April and late October 1962. All but six took place in the vicinity of Christmas Island, then a British mandate in the Line Islands some 1,300 miles south of Hawaii.1 Although the Navy had originally intended to conduct their Polaris and ASROC system trials in the Atlantic, with the Polaris target area near Ascension Island, both Navy tests were eventually rolled into Operation Dominic, which had been planned primarily as a series of air drops. The Polaris and ASROC tests were given the code names Frigate Bird and Swordfish, respectively, and became the fifth and ninth shots in the test sequence. For Frigate Bird, an impact area was selected northeast of Christmas Island, which served both as a communications and logistics hub and a base for the sampling aircraft that gathered technical data from the detonations.

Implementing Frigate Bird

Specifically organized in November 1961 to carry out Operation Dominic, Joint Task Force 8 (JTF-8) was commanded by MAJ GEN Alfred Starbird, USA, of the Army Corps of Engineers, formerly the director for military applications at the Atomic Energy Commission. Under Starbird were Navy and Air Force military deputies and a civilian deputy for scientific affairs. The nuclear ASROC test was assigned to JTF-8 in mid-January 1962, but it was March before the Joint Chiefs of Staff granted final approval for the Polaris test. Moreover, the British had only agreed to the use of Christmas Island in early February, and an extraordinary logistics effort was needed to ready the base for the planned start of testing in late April. Ultimately, MAJ GEN Starbird designated his Navy deputy, RADM Lloyd Mustin, USN, as Commander, Joint Task Group 8.8 (JTG-8.8), charged specifically with executing Frigate Bird and Swordfish.2

The Navy had originally planned the Polaris system test for the Atlantic area, because at this early stage of the strategic submarine program, SSBN deterrent patrols had not yet been extended into the Pacific. Of the six SSBNs then operational, Ethan Allen – commanded by CAPT Paul Lacy, USN – was the newest, having been commissioned less than a year earlier, and she was designated as the firing ship.3 The relatively late decision to transfer Frigate Bird to the Pacific created a challenging schedule problem, particularly since MAJ GEN Starbird and his staff wanted the two Navy tests executed as early as possible in the Dominic test series – i.e., during the first half of May.

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(above) The first two nuclear detonations subsequent to the wartime atomic bombs at Hiroshima and Nagasaki comprised Operation Crossroads, conducted at Bikini Atoll in July 1946 to measure nuclear weapon effects on warships. This familiar image shows Baker, the second of the two tests, in which a 63-kiloton warhead was exploded 90 feet under water.
(below) Seen from an observing ship 120 miles away, the Frigate Bird fireball appears low on the horizon.
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Accordingly, Ethan Allen hurriedly left Charleston, South Carolina on 19 April, four of her 16 standard Polaris missiles replaced by slightly modified weapons fitted with tracking beacons and command-destruct systems. The submarine passed through the Panama Canal and made a high-speed submerged transit to rendezvous on 2 May with surface units of TG-8.8 assembled at the firing point approximately 1,500 miles northeast of Christmas Island.

The firing and impact points had been selected with some care. Because the nominal range of the Polaris A-1 missile was approximately 1,200 miles, the launch point was chosen to be at least 1,300 miles from the nearest inhabited areas. Originally, this was expected to be near Johnston Island, approximately 1,400 miles northwest of Christmas Island, because Johnston was also an Operation Dominic hub, and logistic and test support would have been easier. However, with so little time available for Ethan Allen to reach firing position from the Panama Canal, CJTF-8 opted to launch from a point east of the target area. The intended nuclear detonation was to be an air burst at an altitude of 11,000 feet. Eye-safe considerations dictated that no uncontrolled observers could be within 150 miles of the explosion, which pushed the intended burst point northeasterly, away from Christmas
and other islands of the chain. Ultimately, an aim point was selected 525 miles east-northeast of Christmas Island, just within the operating radius of the sampling aircraft staged from the airfield there.

In addition to Ethan Allen, TU-8.8 units in the vicinity of the launch point included the aircraft carrier USS Yorktown (CVS-10) with Carrier Air Group 55 embarked; the destroyers Maddox (DD-731), Brush (DD-745), Samuel N. Moore (DD-747), and Preston (DD-795); and the range safety ship, USS Norton Sound (AVM-1), in which RADM Mustin flew his flag. Downrange, the diesel-electric submarines USS Carbonero (SS-337) and USS Medregal (SS-480) were submerged at periscope depth 25 miles from the burst point and offset 45 degrees on either side of the flight path. The two observation submarines were equipped with both periscope cameras for visual documentation and so-called “bhangmeters” for measuring the warhead yield.4 In addition, several measurement aircraft, flown from Christmas Island, were positioned to collect cloud samples and perform other diagnostic tests.

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Fall 2004 Cover