Tag Archives: Intermediate Range Ballistic Missile

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

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

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.

At 08:46:28 UTC, a Douglas SM-75 Thor intermediate-range ballistic missile (IRBM) was launched from the Thor missile complex on Johnston Island, carrying a W-49 warhead in an AVCO Corporation Mk-2 reentry vehicle. The Mark 4/W-49 reached a peak altitude of 600 miles (965 kilometers) along a ballistic trajectory then began a descent.

Starfish Prime fireball was visible from Honolulu, Oahu. Hawaii.
Starfish Prime fireball was visible from Honolulu, Oahu, Hawaii, 898 miles (1,445.2 kilometers) from Ground Zero.

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.

A Douglas SM-75/PGM-17A Thor IRBM. (U.S. Air Force)
A Douglas SM-75 Thor IRBM. (U.S. Air Force)

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.

The Douglas Aircraft Company SM-75 Thor (redesignated PGM-17A in 1963) was a single-stage nuclear-armed ballistic missile, 65 feet (19.812 meters) long and 8 feet (2.438 meters) in diameter. It weighed 6,890 pounds (3,125.3 kilograms) empty and 110,000 pounds (49,895.2 kilograms) when fueled.

The SM-75 was powered by one Rocketdyne LR79-NA-9 rocket engine which produced 150,000 pounds of thrust. Two Rocketdyne LR101-NA vernier engines of 1,000 pounds thrust, each, provided directional control and thrust adjustments. The Thor was fueled with kerosene and liquid oxygen sufficient for 165 seconds of 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)

© 2018, Bryan R. Swopes

Facebooktwittergoogle_plusredditpinterestlinkedinmailby feather

14 October 1962

This is one of the reconnaissance photographs taken by Major Richard S. Heyser  from his Lockheed U-2, flying at 72,500 feet over Cuba, 14 October 1962. (U.S. Air Force)

14 October 1962: Major Richard Stephen (“Steve”) Heyser, a pilot with the 4028th Strategic Reconnaissance Squadron, 4080th Strategic Reconnaissance Wing, United States Air Force, boarded Item 342, his Top Secret reconnaissance airplane, at Edwards Air Force Base, California. Over the next seven hours he flew from Edwards to McCoy AFB, near Orlando, Florida, landing there at 0920 EST.

Major Richard S. Heyser, U.S. Air Force, with a Lockheed U-2. Major Heyser is wearing a MC-3 capstan-type partial-pressure suit for protection at high altitudes. (U.S. Air Force)
Major Richard S. Heyser, U.S. Air Force, with a Lockheed U-2. Major Heyser is wearing a MC-3 capstan-type partial-pressure suit for protection at high altitudes. (U.S. Air Force)

But first, Steve Heyser and Item 342 flew over the island of Cuba at an altitude of 72,500 feet (22,098 meters). Over the island for just seven minutes, Heyser used the airplane’s cameras to take some of the most important photographs of the Twentieth Century.

Item 342 was a Lockheed U-2F. Designed by Clarence L. (“Kelly”) Johnson at the “Skunk Works,” it was a very high altitude, single-seat, single-engine airplane built for the Central Intelligence Agency. Item 342 carried a U.S. Air Force number on its tail, 66675. This represented its serial number, 56-6675.

It had been built at Burbank, then its sub-assemblies were flown aboard a C-124 Globemaster transport to a secret facility at Groom Lake, Nevada, called “The Ranch,” where it was assembled and flown.

Originally a U-2A, Item 342 was modified to a U-2C, and then to a U-2F, capable of inflight refueling.

Major Heyser had been at Edwards AFB to complete training on the latest configuration when he was assigned to this mission.

A Lockheed U-2A, 56-6708, “Item 375”. (U.S. Air Force)

Major Heyser’s photographs showed Russian SS-4 Sandal intermediate range nuclear-armed missiles being placed in Cuba, with SA-2 Guideline radar-guided surface-to-air anti-aircraft missile sites surrounding the nuclear missile sites.

President John F. Kennedy ordered a blockade of Cuba and demanded that Russia remove the missiles. Premier Nikita Khrushchev refused. The entire U.S. military was brought to readiness for immediate war. This was The Cuban Missile Crisis. World War III was imminent.

(Left to Right) Major Richard S. Heyser, General Curtis E. LeMay and President John F. Kennedy, at the White House, October 1962. (Associated Press)

Richard S. Heyser died 6 October 2008.

© 2017, Bryan R. Swopes

Facebooktwittergoogle_plusredditpinterestlinkedinmailby feather