Tag Archives: Nuclear Weapon Test

6 April 1955, 18:00:04.1 UTC

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Operation Teapot HA fireball, 6 April 1955. (U.S. Air Force)
Operation Teapot HA fireball, 6 April 1955. (U.S. Air Force)

6 April 1955: At 10:00:04.1 a.m. local time (1800 GMT), a Convair B-36H assigned to the 4925th Test Group (Atomic) at Kirtland Air Force Base, New Mexico dropped an atomic weapon from 42,000 feet (12,802 meters) over the Nevada Test Site, Area 1. The bomb was parachute-retarded to slow its fall so that the bomber could escape its blast effects.

The weapon was a test device produced by the Los Alamos Scientific Laboratory to investigate its use as an air-to-air anti-aircraft missile warhead. The bomb detonated at 36,620 feet (11,162 meters) with an explosive force of 3.2 kilotons. Because of the altitude of the explosion, there was no significant fallout.

All test observers (with goggles) agreed that the fireball appeared more intensely bright than in events of similar yield fired at lower altitude.

—United States High-Altitude Test Experiences by Herman Hoerlin, Los Alamos Scientific Laboratory, June 1976, at Page 12.

Captain William L. Hickey, USAF, pilot of a Convair B-36 Peacemaker very long-range heavy bomber during Operation Teapot, 1955. Captain Hickey is wearing a David Clark Co. S-2 capstan-type partial-pressure suit and K-1 helmet for protection at high altitude. (U.S. Air Force via Jet Pilot Overseas)
Captain William L. Hickey, USAF, pilot of a Convair B-36 Peacemaker very long-range heavy bomber during Operation Teapot, 1955. Captain Hickey is wearing a David Clark Co. S-2 capstan-type partial-pressure suit and K-1 helmet for protection at high altitude. (Jet Pilot Overseas)

The warhead was designed at the Los Alamos Scientific Laboratory (LASL) in New Mexico and was similar to the Wasp Prime device, which had been detonated earlier in the Operation Teapot test series. It used a spherical implosion device. The warhead was a 17-inch (43.2 centimeters) diameter sphere weighing approximately 125 pounds (56.7 kilograms). It was placed inside a Mark 5 bomb case which weighed 1,085 pounds (492.2 kilograms).

This was the only bomb dropped by parachute at the Nevada Test Site.

Flight crew of a Convair B-36 Peacemaker, 4925th Test Group (Atomic) during Operation Teapot, 1955. The crewmen are wearing David Clark Co. S-2 capstan-type partial-pressure suits for protection at high altitude. The two white helmets are early K-1 "split shell" 2-piece helmets, while the green helmets are later K-1 1-piece models. (U.S. Air Force via Jet Pilot Overseas)
Flight crew of a Convair B-36 Peacemaker, 4925th Test Group (Atomic) during Operation Teapot, 1955. The crewmen are wearing David Clark Co. S-2 capstan-type partial-pressure suits for protection at high altitude. The two white helmets are early K-1 “split shell” two-piece helmets, while the green helmets are later K-1 one-piece models. (Jet Pilot Overseas)

The Convair B-36H Peacemaker was the definitive version of the ten engine bomber, with 156 B-36H/RB-36H built out of the total production of 383 Peacemakers. It is similar to the previous B-36F variant, though with a second flight engineer’s position, a revised crew compartment, and improved radar controlling the two 20 mm autocannons in the tail turret.

The B-36H was 162 feet, 1 inch (49.403 meters) long with a wingspan of 230 feet (70.104 meters) and overall height of 46 feet, 8 inches (14.224 meters). The total area of its wings was 4,772 square feet (443.3 square meters). The wings’ leading edges were swept aft 15° 5′ 39″. Their angle of incidence was 3°, with -2° twist and 2° dihedral. The empty weight of the B-36H was 165,887pounds (75,245 kilograms) and the maximum takeoff weight is 357,500 pounds (162,159 kilograms).

Three flight crewmen don their parachutes before boarding the B-36H Peacemaker for Operation Teapot HA, 5 April 1955. The automobile behind them is a 1955 Chevrolet Bel Air 4-door sedan. (U.S. Air Force)
Three flight crewmen don their parachutes before boarding the B-36H Peacemaker for Operation Teapot HA, 5 April 1955. The automobile behind them is a 1955 Chevrolet Bel Air 4-door sedan. (U.S. Air Force)

The B-36H has ten engines. There are six air-cooled, supercharged 4,362.49 cubic-inch-displacement (71.49 liter) Pratt & Whitney Wasp Major C6 (R-4360-53) four-row, 28-cylinder radial engines placed inside the wings in a pusher configuration. These had a compression ratio of 6.7:1 and required 115/145 aviation gasoline. The R-4360-53 had a Normal Power rating of 2,800 horsepower at 2,600 r.p.m. Its Military Power rating was 3,500 horsepower at 2,800 r.p.m., and 3,800 horsepower at 2,800 r.p.m. with water injection—the same for Takeoff. The engines turned three-bladed Curtiss Electric constant-speed, reversible propellers with a diameter of 19 feet, 0 inches (5.791 meters) through a 0.375:1 gear reduction. The R-4360-53 is 9 feet, 9.00 inches (2.972 meters) long, 4 feet, 7.00 inches (1.397 meters) in diameter, and weighs 4,040 pounds (1,832.5 kilograms).

A smoke ring formed following the detonation of the Operation Teapot HA test. Contrails of the test aircraft are visible. (U.S. Air Force)

Four General Electric J47-GE-19 turbojet engines are suspended under the wings in two-engine pods. The J47 is a  single-shaft axial-flow turbojet engine with a 12-stage compressor section, 8 combustion chambers, and single-stage turbine. The J47-GE-19 was modified to run on gasoline and was rated at 5,200 pounds of thrust (23.131 kilonewtons).

The B-36H was the fastest variant of the Peacemaker series, with a cruise speed of  216 knots (249 miles per hour/400 kilometers per hour) and a maximum speed of 382 knots (440 miles per hour/707 kilometers per hour) at 35,500 feet (10,820 meters). The service ceiling was 47,000 feet (14,326 meters) and its combat radius was 3,190 nautical miles (3,671 statute miles/5,908 kilometers). The ferry range was 7,120 nautical miles (8,194 statute miles/13,186 kilometers).

Convair RB-36H-40-CF 51-13741 Featherweight III. (U.S. Air Force)

The B-36H has six remotely-controlled retractable gun turrets mounting two M24A1 20 mm autocannon, each, with 600 rounds of ammunition per gun. The tail turret was radar-controlled, and another 2 guns were mounted in the nose.

The B-36 was designed during World War II, when nuclear weapons were unknown to the manufacturer. The bomber was built to carry up to 86,000 pounds (39,009 kilograms) of conventional bombs in fours bomb bays. It could carry two 43,000 pound ( kilogram) T-12 Cloudmakers, a conventional explosive earth-penetrating bomb, or several Mk.15 thermonuclear bombs. By combining the bomb bays, one Mk.17 25-megaton thermonuclear bomb could be carried.

This Convair RB-36D-5-CF, 49-2686, is similar in appearance to the B-36H used in Operation Teapot HA. (U.S. Air Force)
This Convair RB-36D-5-CF, 49-2686, is similar in appearance to the B-36H used in Operation Teapot HA. (U.S. Air Force)

© 2019, Bryan R. Swopes

4 November 1962, 06:30 GMT

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Dominic Tightrope fireball, 00:00 GMT, 4 November 1962. (Nuclear Weapons Archive)
Dominic Tightrope fireball, 06:30 GMT, 4 November 1962. (Nuclear Weapons Archive)

4 November 1962: A Western Electric M6 Nike Hercules air-defense guided missile was launched from Johnston Island in the North Pacific Ocean. The missile was armed with a  W-31 Mod 1 nuclear warhead, and had been modified to include a command arm/fire capability, and an automatic disarm feature.

At an altitude of 69,000 feet (21,031 meters), 2 miles (3.2 kilometers) south-southwest of the island, the warhead detonated with an explosive yield of 12 kilotons.

This nuclear weapon effects test, Dominic Tightrope, was the final test of the Operation Dominic I test series, and was the last atmospheric nuclear test conducted by the United States.

The Nike Hercules was a long-range, high-altitude surface-to-air guided missile, designed and produced by Western Electric Company and the Douglas Aircraft Company. Douglas manufactured the missile at Charlotte, North Carolina. It was a two-stage missile with a cluster of four Hercules Powder Company M5E1 solid-fuel rocket engines as the boost stage.

The Nike Hercules had an overall length of 41 feet, 1.35 inches (12.531 meters). Its weight was 10,710 pounds (4,858 kilograms). The Hercules could reach an altitude of 100,000 feet (30,480 meters) and had a range of 90 miles (145 kilometers). The missile’s maximum speed was Mach 3.65.

The booster stage was 14 feet, 2.845 inches (4.339 meters) long and had a maximum diameter of 3 feet, 7.25 inches (1.099 meters). There were four stabilizing fins spaced at 90°. The fin span was 11 feet, 5.88 inches (3.502 meters). The leading edges were swept aft 24.23°. The booster stage produced 173,600 pounds of thrust (772.211 kilonewtons) and burned for 3.4 seconds.

Nike Hercules second stage.

The second stage was 26 feet, 10.500 inches (8.192 meters) long with a maximum diameter of 2 feet, 7.50 inches (0.800 meters). It had four triangular wings and four small “linealizer” fins, which were also spaced 90°. The maximum wing span was 7 feet, 4.00 inches (2.235 meters). The missile was powered by a Thiokol Chemical Corporation M30 solid-fuel rocket engine which produced 13,750 pounds of thrust (61.163 kilonewtons) and had a burn time of 29 seconds.

A Nike Hercules air defense missile launch. (U.S. Army)
A Nike Hercules air defense missile launch. (U.S. Army)

The Nike air defense missile system used multiple radars to track incoming target aircraft and the outgoing missile. Computer systems analyzed the data and signals were sent to guide the missile toward the target. This was a complex system and multiple missiles were based together at missile sites around the defended area.

The Hercules could be armed with either a M17 high explosive fragmentation warhead or a 20–40 kiloton W-31 nuclear warhead. Although designed to attack jet aircraft, the Nike Hercules also successfully intercepted guided and ballistic missiles, and had a surface-to-surface capability.

The Western Electric SAM-A-25 Nike B was renamed Nike Hercules in 1956 while still in development. It was redesignated Guided Missile, Air Defense M6 in 1958, and MIM-14 in 1963. (“MIM” is Department of Defense terminology for a mobile, ground-launched interceptor missile.) About 25,000 Nike Hercules missiles were built. Initially deployed in 1958, it remained in service with the U.S. Army until 1984.

The W-31 was a boosted fission implosion warhead designed by the Los Alamos Scientific Laboratory. It weighed 900 pounds (408 kilograms) and had a selectable yield of from 2 to 40 kilotons. About 2,550 warheads were produced and remained in service until 1989.

A battery of U.S. Army Nike Hercules SAM-A-25 surface-to-air guided missiles. (U.S. Army)
A battery of U.S. Army Nike Hercules MIM-14 surface-to-air guided missiles. (U.S. Army)

© 2018, Bryan R. Swopes

30 October 1961

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Tupolev Tu 95 carrying Tsar Bomba
Tupolev Tu-95V No. 5800302 carrying the RDS-220 bomb.

30 October 1961: At 9:30 a.m., specially modified Tupolev Tu-95V “Bear A” bomber, No. 5800302, under the command of Major Andrey Ergorovich Durnovtsev of the 409th Heavy Bomber Air Regiment, departed Olenegorsk Air Base, 92 kilometers (57 miles) south of Murmansk, at 9:30 a.m. The bomber carried a nine-man crew, including navigator Major Ivan Nikoforovich Mite.

The Tu-95 was accompanied by a Tupolev Tu-16 instrumentation ship (No. 3709), under the command of Colonel Vladimir Fedorovich Martynenko. Some sources say that the two bombers were escorted by a flight of fully-armed fighters.

Major Durnovtsev’s mission was to carry out the Soviet Union’s 130th nuclear weapons test. The Tu-95 carried a single RDS-220, a three-stage radiation-implosion thermonuclear bomb. It was 8 meters (26.25 feet) long, with a diameter of 2.1 meters (6.89 feet), and weighed approximately 27,000 kilograms (59,525 pounds). The bomb was variously known as “Big Ivan” or “Tsar Bomba” (King of Bombs).

Fully assembled RDS-220 three-stage radiation implosion thermonuclear bomb, with retarding parachute in place, at Arzamas-16 .

The Tu-95 dropped the RDS-220 from an altitude of 10,500 meters (34,449 feet) over the D-II test range, 15 kilometers (9 miles) north of the Mityushikha Strait on Novaya Zemlya. The bomb was retarded by parachute to allow the Bear time to escape the blast effects. After falling for 3 minutes, 8 seconds, at 11:33 a.m., the bomb detonated 4,000 meters (13,123 feet) above the surface of Novaya Zemlya. A bright flash of light lasted for 30 seconds and finally faded away after 70 seconds.

45 seconds after detonation, the nuclear cloud reached a height of 30 kilometers (19 miles), then spread outward, reaching a maximum diameter of 95 kilometers (59 miles).

Major Durnovtsev's Tupolev Tu-95N Bear A, carrying the RDS-220 bomb to the target. A Tu-16 instrumentation aircraft is just behind, on the bomber's left quarter.
Major Durnovtsev’s Tupolev Tu-95V “Bear A,” carrying the RDS-220 bomb to the target. A Tu-16 instrumentation aircraft is just behind, on the bomber’s left quarter.
The RDS-220 bomb just after drop. The retarding parachute is beginning to deploy.
“Big Ivan” with first stage parachute deployed.

Major Durnovtsev’s Tu-95 was approximately 39 kilometers (24 miles) away for “ground zero” at the time of the explosion. As it continued to fly away from the blast, the shock waves finally caught up to bomber at a distance of 115 kilometers (71 miles), 8 minutes, 20 seconds after they had released the bomb.

At the same time, a secret United States Air Force Boeing JKC-135A Stratotanker instrumentation aircraft, Speed Light Bravo, 55-3127, had flown closer to ground zero to gather data about the air burst. It was so close that its special anti-radiation paint was scorched. (55-3127 was later converted to the NKC-135A airborne laboratory configuration to support the Limited Test Ban Treaty of 1963. It was returned to tanker configuration in the 1980s. Later, 55-3127 served as a test bed aircraft for the Aeronautical Systems Division at Wright-Patterson  It was retired to Davis-Monthan Air Force Base in 1992.)

Speed Light Bravo, Boeing JKC-135A Stratotanker 55-3127.

After the nuclear explosion data was analyzed by the Foreign Weapons Evaluation Panel (the “Bethe Panel”) the RDS-220 yield was estimated at 57 megatons. This was the largest nuclear weapon detonation in history. It was also the “cleanest,” with 97% of the energy yield produced by fusion. Relative to the size of the explosion, very little fallout was produced.

Tsar Bomba fireball over Novaya Zemlya, 11:32 a.m., 30 October 1961. The fireball has reached a diameter of 5 miles (8 kilometers). Shock waves reflecting off of the ground caused the slight flattening of the bottom of the fireball.

All buildings in the town of Severny, 55 kilometers (34.2 miles) from Ground Zero, were destroyed. Wooden buildings as far as 200 kilometers (124 miles) were destroyed or heavily damaged.

A visible shock wave in the air was seen at a distance of 700 kilometers (435 miles). The shock wave from the explosion traveled around the world three times.

The mushroom cloud of Tsar Bomba climbs into the stratosphere.

Following the test, Major Durnovtsev was promoted to the rank of Lieutenant Colonel and named Hero of the Soviet Union.

The crater created by the Tsar Bomba test, 30 October 1961.

Bear No. 5800302 was ordered in 1955 and completed in 1956. The Tupolev Tu-95 is a long range strategic bomber. It is 151 feet, 6 inches (46.2 meters) long with a wingspan of 164 feet, 5 inches (50.10 meters). The wings are swept at a 35° angle. The bomber is powered by four Kuznetsov NK-12M turboprop engines, producing 14,800 shaft horsepower, each, and turning 8-bladed counter-rotating propellers. It weighs 90,000 kilograms (198,416 pounds) empty, with a maximum takeoff weight of 188,000 kilograms (414,469 pounds). The Bear has a maximum speed of 920 kilometers per hour (572 miles per hour) and an unrefueled range of 15,000 kilometers (9,321 miles). (The Bear A is capable of inflight refueling.) Service ceiling is 13,716 meters (45,000 feet).

Approximately 72 of these aircraft remain in service with the Russian Federation. The current variant is the Tupolev Tu-95MS “Bear H.” Recently, individual bombers have been taken out of service to be modernized by the Beriev Aircraft Company at Taganrog, Russia. The modernized Bear is designated Tu-95MSM. It is expected that 20 Tu-95s will be upgraded.

A current production Tupolev Tu-95 Bear-H strategic bomber. (U.S. Air Force)
A current production Tupolev Tu-95MS Bear H strategic bomber. (Royal Air Force)

Андрей Егорович Дурновцев (Andrey Ergorovich Durnovtsev) was born 14 January 1923 at Verkhney, a village in the Krasnoyarsk Krai of Siberia. He graduated from high school in 1940.

Durnovtsev was inducted into the Red Army 19 July 1942 and sent to the Irkutsk Military School of Aviation Mechanics, graduating in November 1943. He was promoted to sergeant. Sergeant Durnovtsev request assignment for pilot training, and was sent to the 8th Military Aviation School for initial flight training. In August 1945, he was sent to complete training in long-range bombers at the Engels Military Aviation Pilot School (VAUL). He graduated in 1948.

Lieutenant Durnovtsev next attended the Ryazan Higher Officers’ School, studying the combat application of long-ranger bombers. He was assigned as a pilot with the 330th Bomber Aviation Regiment. Durnovtsev served as an aircraft commander, detachment commnder, then deputy squadron commander.

Lieutenant Colonel Durnovtsev was named Hero of the Soviet Union by decree of the Presidium of the Supreme Soviet, 7 March 1962, “for courage and bravery shown in the development of new military equipment.”

Lieutenant Colonel Drnovtsev retired in 1965. During his military career, he had been awarded the Gold Star Medal, the Order of Lenin, the Order of the Red Star, and the Medal for Military Merit.

Lieutenant Colonel Andrey Ergorovich Durnovtsev, Hero of the Soviet Union, died in Kiev, 24 October 1976, at the age of 53 years.

Майор Андрей Дурновцев

A recently declassified 40-minute video of the test can be viewed on YouTube at:

© 2020, Bryan R. Swopes

19 July 1957, 14:00:04.6 UTC

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Northrop F-89J Scorpion 53-2547 fires a live MB-1 rocket during Operation Plumbbob John, 1400 GMT, 19 July 1957. (U.S. Air Force)

During 1957, a series of 29 nuclear weapons tests were carried out at the United States’ Nevada Test Site, 65 miles (105 kilometers) northwest of Las Vegas, Nevada, under Project Plumbbob. Shot John was the first and only firing of a live, nuclear-armed, air-to-air anti-aircraft missile.

On Friday morning, 19 July 1957, a United States Air Force Northrop F-89J Scorpion interceptor, serial number 53-2547, flown by Captain Eric W. Hutchison, Pilot, and Captain Alfred C. Barbee, Radar Intercept Officer, launched a Genie MB-1 unguided rocket at an altitude of 18,500 feet (5,640 meters) over NTS Area 10.

(DoE)

The rocket accelerated to Mach 3 and traveled 2.6 miles (4,250 meters) in 4.5 seconds when, at 07:00:04.6 a.m., Pacific Daylight Savings Time (14:00 UTC), its W-25 warhead was detonated by a signal from a ground station. The resulting explosive yield was 1.7 kilotons.

Plumbbob John fireball as seen from Indian Springs Air Base, 30 miles away from the detonation. The aircraft in the foreground is a Northrop F-89J Scorpion, a sister-ship of the launch aircraft. (U.S. Air Force)

Interestingly, five U.S. Air Force officers and a photographer were standing directly under the air burst. This was an attempt by the Air Force to assuage public fears about the use of nuclear-armed anti-aircraft missiles over populated areas.

Five Air Force officers stand at ground zero of an atomic bomb test at a Nevada test site on July 19, 1957.

The Northrop Corporation F-89J Scorpion was a two-place, twin-engine, sub-sonic all-weather interceptor. It was flown by a pilot and radar intercept officer in a tandem cockpit. It had a straight wing at mid-fuselage and a “T” tail horizontal stabilizer. Earlier variants of the Scorpion were armed with machine guns and rockets, but the F-89J carried only rockets and guided missiles.

The fireball of the W-25 warhead, photographed from approximately 5 miles. (U.S. Air Force)
The fireball of the W-25 warhead, photographed from approximately 5 miles. (Photo courtesy of National Nuclear Security Administration/Nevada Field Office)

F-89J 53-2547 was built as an F-89D-60-NO Scorpion, and was one of 350 D-models which were upgraded to the F-89J standard. It was a missile-armed all-weather interceptor with a two man crew assigned to the Air Defense Command.

The Northrop F-89J Scorpion was 53 feet, 8.4 inches long (16.368 meters) with a wingspan of 59 feet, 9.6 inches (18.227 meters) and overall height of 17 feet, 6 inches (5.334 meters). The leading edge of the interceptor’s wings were swept aft 5° 8′. The angle of incidence was 1° 30′, with no twist, and 1° 0′ dihedral. The total wing area was 606 square feet (56.30 square meters).

The F-89J had an empty weight of 26,883 pounds (12,194 kilograms) and maximum takeoff weight of 47,719 pounds (21,645 kilograms).

The F-89J Scorpion was powered by two General Electric-designed, Allison Engine Company-built, J35-A-35 engines. The J35 was a single-spool, axial-flow turbojet engine with an 11-stage compressor section and single-stage turbine. The J35-A-33 had a Normal (continuous) power rating of 4,855 pounds of thrust (21.596 kilonewtons) at 7,400 r.p.m. The Military Power rating was 5,440 pounds (24.198 kilonewtons) at 8,000 r.p.m. (30 minute limit), and it could produce a maximum 7,200 pounds of thrust (32.027 kilonewtons) at 8,000 r.p.m., with afterburner (5 minute limit). The engine was 16 feet, 3.5 inches (4.966 meters) long, 3 feet, 1.0 inches (0.940 meters) in diameter and weighed 2,830 pounds (1,284 kilograms).

Cutaway illustration of J35 turbojet engine. (General Electric)

The F-89J had a cruise speed of 402 knots (463 miles per hour/745 kilometers per hour) and a maximum speed of 528 knots (608 miles per hour/978 kilometers per hour) at 11,100 feet (3,383 meters). The service ceiling was 43,900 feet (13,381 meters). The interceptor’s combat radius was 435 nautical miles (501 statute miles/806 kilometers), and the maximum ferry range was 1,498 nautical miles (1,724 statute miles/2774 kilometers).

The F-89J could be armed with two MB-1 Genie rockets and four Hughes GAR-2A (AIM-4C) Falcon infrared-seeking air-to-air missiles; or two MB-1 Genies and 104 2.75-inch Folding-Fin Aerial Rockets (FFAR).

F-89s served with the U.S. Air Force and Air National Guard from 1948 until 1969. Northrop F-89J Scorpion 53-2547 was transferred to the Montana Air National Guard in 1960. It is on display at the Air National Guard Base, Great Falls, Montana.

A Douglas MB-1 Genie nuclear-armed air-to-air rocket is loaded aboard the F-89 Scorpion in preparation for Operation Plumbbob John. (U.S. Air Force)
A Douglas MB-1 Genie nuclear-armed air-to-air rocket is loaded aboard the F-89 Scorpion in preparation for Operation Plumbbob John. (U.S. Air Force)

The Douglas Aircraft Company, Missiles and Space Systems Division MB-1 Genie (AIR-2 after June 1963) was an unguided, nuclear-armed, air-to-air anti-aircraft rocket. Its solid-fuel Thiokol SR49-TC-1 engine produced 36,500 pounds of thrust (162.360 kilonewtons) and gave the Genie a maximum speed of Mach 3.3. Its range was 6 miles (9.6 kilometers). The rocket weighed 822 pounds (373 kilograms) with its W-25 warhead, and was 9 feet, 8 inches (2.946 meters) in length, with a maximum diameter of 1 foot, 5.5 inches (0.445 meters). The fins spanned 3 feet, 4 inches (1.118 meters). In production from 1957 to 1962, 3,150 missiles were produced. The Genie was in service from 1957 to 1988.

Douglas MB-1 (ATR-2A) Genie air-to-air rocket. (Nuclear Weapons Archive)

The W-25 was a Los Alamos Scientific Laboratory-designed anti-aircraft warhead. It was a fission device, using implosion of both uranium and plutonium. The warhead’s diameter was 17.35 inches, and it was 26.6 inches long. The warhead weighed 221 pounds (100 kilograms). The W-25 was produced from May 1957 to May 1960. All had been retired by December 1984.

Detonation was by time delay fuse. Lethal radius of the warhead was estimated to be approximately 1,000 feet (300 meters).

Plumbbob John. The Nevada State Journal described “a weird spray trailing earthward.”

© 2018, Bryan R. Swopes

9 July 1962, 09:00:09 UTC, T + 13:41

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Fireball of Operation Dominic-Fishbowl Starfish Prime, 248 miles (399.1 kilometers) above the Pacific Ocean, 9 July 1962. (U.S. Department of Defense)

9 July 1962: At 09:00:09 UTC, the United States detonated a thermonuclear warhead over the Pacific Ocean. This was part of the Operation Dominic-Fishbowl test series at Johnston Island, and was designated Starfish Prime.

A Thor missile is launched from Johnston Island. Note the instrumentation pods at the base of the rocket. (Johnston Memories)

At 08:46:28 UTC, a Douglas Thor DSV2E orbital launch vehicle, serial number 195,  was launched from missile complex LE-1 on Johnston Island, carrying a W-49 warhead in an AVCO Corporation Mk-2 reentry vehicle. The rocket also carried three instrumentation pods which were jettisoned at pre-selected altitudes. The W-49 reached a peak altitude of 600 miles (965 kilometers) along a ballistic trajectory, and then began to descend.

Starfish Prime fireball was visible from Honolulu, Oahu, Hawaii, 898 miles (1,445.2 kilometers) from Ground Zero. “Widespread red air glow (6300 å) amid dark clouds, caused mostly by x-ray-excited atomic oxygen (i.e., oxygen by photoelectrons liberated by Starfish X-rays)” (Commission to Assess Threat to the United States from Electromagnetic Pulse (EMP) Attack, 2004, at Page 5)
Starfish Prime (atomicarchive.com)

The W-49 detonated 36 kilometers (22 miles) southwest of Johnston Island at an altitude of 400 kilometers (246 miles) with an explosive yield of 1.45 megatons. The point of detonation deviated from the planned Air Zero by 1,890 feet (576 meters) to the north, 2,190 feet (668 meters) east, and +617 feet (188 meters) in altitude. The fireball was clearly visible in the Hawaiian Islands, more than 800 miles (1,288 kilometers) away.

The electromagnetic pulse (EMP) damaged electrical systems in The Islands, cutting power, damaging equipment and interrupting telephone systems. Brilliant auroras were visible, lasting about 7 minutes.

Telstar, an American communications satellite that was placed in Earth orbit the following day, was also damaged by residual radiation from the detonation.

The Starfish Prime experiment was for the purpose of “Evaluation of missile kill mechanisms produced by a high altitude nuclear detonation.” The electromagnetic effects on communications were also studied.

A Douglas SM-75/PGM-17A Thor IRBM. (U.S. Air Force)
A Douglas SM-75 Thor IRBM (DM-18A) is launched at Launch Complex 17B, Cape Canaveral Air Force Station, Florida, 12 May 1959. (U.S. Air Force)

The Thor DSV2E was an orbital launch variant of the Douglas Aircraft Company SM-75 Thor IRBM. This was a single-stage nuclear-armed intermediate-range ballistic missile, 61 feet, 3.91 (19.692 meters) long and 8 feet, 0.00 inches (2.438 meters) in diameter. With the Mk-2 reentry vehicle, the overall length of the missile was 63 feet, 7.38 inches (19.390 meters). It weighed 109,800 pounds (49,805 kilograms) at liftoff and 6,889 pounds (3,124 kilograms) at burnout.

The SM-75 was powered by one Rocketdyne LR79-NA-9 rocket engine which produced 150,000 pounds of thrust (667.23 kilonewtons). Two Rocketdyne LR101-NA-9 vernier engines of 1,000 pounds thrust (4.45 kN), each, provided directional control and thrust adjustments. The Thor was fueled with kerosene and liquid oxygen sufficient for 156 seconds of main engine burn time.

The Thor could reach a maximum speed of 11,020 miles per hour (17,735 kilometers per hour) and had a maximum range of 1,500 miles (2,414 kilometers).

The W-49 thermonuclear warhead was designed by the Los Alamos Scientific Laboratory (LASL) and is believed to be a development of the earlier B-28 two-stage radiation-implosion bomb. It incorporated a 10-kiloton W-34 warhead as a gas-boosted fission primary, and had a one-point-safe safety system. The warhead had a diameter of 1 foot, 8 inches (0.508 meters) and length of  4 feet, 6.3 inches (1.379 meters). It weighed 1,665 pounds (755 kilograms).

The flash from the Starfish-Prime detonation, photographed from Maui in the Hawaiian Islands 15 seconds after detonation. (Los Alamos National Laboratory)
The flash from the Starfish-Prime detonation, photographed from Maui in the Hawaiian Islands, 15 seconds after detonation. (Los Alamos National Laboratory)

© 2020, Bryan R. Swopes