Today in 1962, the United States conducted Tightrope—its last fully atmospheric nuclear test—as part of Operation Fishbowl. A Nike Hercules SAM was fired 69,000 feet into the sky where its W31 warhead exploded with a reported yield of 10 kilotons 2 miles SSW of Johnston Island.
Subsequent US tests that took place in the atmosphere included Operation Roller Coaster, four joint US-UK zero-yield plutonium dispersal safety tests (Double Tracks, Clean Slate I, Clean Slate II, and Clean Slate III) conducted at the Nevada Test Site from May 15 to June 9, 1963.
There were also 4 Project Plowshare “peaceful nuclear explosion” excavation experiments in Nevada that deliberately breached the surface:
Palanquin—April 14, 1965; 4.3kt
Cabriolet—January 26, 1968; 2.3kt
Buggy—March 12, 1968; 5 simultaneous 1.08kt
Schooner—December 8, 1968; 30kt
Here's Buggy:
And here's Schooner, which was an especially messy test, particularly onsite: and
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50 years ago today, the United States conducted its largest-ever underground nuclear test. A Spartan antiballistic missile carrying a W71 warhead was lowered into a 7-foot-wide, 5,873-foot-deep shaft beneath Amchitka Island, Alaska, and detonated. The yield was about 5 Megatons.
The test went ahead only hours after the Supreme Court refused requests to delay it over the Nixon administration’s failure to issue a comprehensive environmental impact statement. Instead, the court agreed with the admin’s claim any delay would upset the “balance of deterrence.”
Here is some remarkable official footage of the preparations for and results of that huge test. I have watched a lot of nuclear test films over the years, and even though Cannikin was entirely underground, this one never fails to send chills down my spine.
Today in 1958—Election Day—a B-47 bomber carrying one unspecified sealed-pit thermonuclear gravity bomb became engulfed in flames on takeoff and crashed from 1,500 feet on private land about 4.5 miles SW of Dyess AFB, near Abilene, Texas. Three crewmen ejected, one was killed.
An explosion of one or more of the assisted-takeoff rockets attached to the fuselage caused the fire. The bomb's conventional high explosives detonated in the crash—the B-47 was "literally blown to bits" per a local reporter—leaving a crater 35 ft. in diameter and 6 ft. deep.
The thermonuclear secondary was damaged but recovered intact, as was the tritium reservoir, which was leaking. The USAF publicly insisted there was "no harmful contamination," although that wasn't true. It only fully cleaned up residual uranium and lead contamination in 2011.
At this moment in 1952 (November 1, local time), the US conducted a test of the first true (albeit undeliverable, weighing 82 tons) H-bomb at Enewetak Atoll. The 10.4-Mt Mike blast vaporized Elugelab Is., leaving behind a 1.2-mi.-wide, 164-ft.-deep crater.
Mike's cloud rose to 57,000' in just 90 sec.; 60 sec. later, it reached 108,000', eventually topping out at 120,000'. It was 60 miles across 30 minutes after detonation. Mike was the fourth largest US nuclear test, with 77% of its yield derived from fission and 23% from fusion.
About 90 minutes after detonation, USAF Capt. Jimmy Robinson, 28, and three others flew F84-G fighters into the massive cloud to collect radioactive fallout samples. Robinson died during a water landing when he ran out of fuel just before reaching Enewetak.airspacemag.com/history-of-fli…
Today in 2000, Congress passed and President Clinton signed the Energy Employees Occupational Illness Compensation Act, providing much-needed compensation and medical benefits to people who mined/milled/transported uranium for nuclear weapons or who built/tested/maintained them.
To date, EEOICPA has provided $20,364,169,497 to 131,783 current/former workers diagnosed w/a radiogenic cancer, chronic beryllium disease, beryllium sensitivity, or chronic silicosis resulting from exposure to radiation, beryllium, or silica while employed at covered facilities.
A related law, the 1990 Radiation Exposure Compensation Act—which expires in July 2022 unless Congress renews it—has provided $1,272,647,112 to 14,110 nuclear test site and uranium workers for radiation-related illnesses linked to their jobs. Another 8,419 have had claims denied.
OTD 55 years ago, this small announcement of a new federal construction contract appeared in the Baltimore Sun. It probably didn't attract much attention, but the facility it referenced would go onto become an integral part of the US government's plans to survive a nuclear war.
Built and operated by the Federal Reserve Bank of Richmond, Virginia, and dedicated on December 10, 1969, the bunker inside Mount Pony, about 70 miles SW of Washington, DC, served as the central hub for all electronic funds transfers in America. But it also had a secret function.
From December 1969 until 1988, the Federal Reserve stored several billion dollars of shrink-wrapped currency—incl. for awhile a large number of $2 bills—in a 23,500 sq. ft. vault in this 139,800 sq. ft. radiation-hardened building. The money was in 9-foot high stacks on pallets.
60 years ago today, the Soviet Union tested the largest-ever thermonuclear bomb—a 50-Mt RDS-220 (originally designed for 100 Mt). The device, later dubbed “Tsar Bomba,” was dropped by a Tu-95 Bear bomber and exploded ~13,123 feet above Novaya Zemlya inside the Arctic Circle.
The RDS-220—designed and built in only 4 months—was 26 ft. long, 6.9 ft. in diameter, and weighed 59,525 lbs., including an 1,800-lb. retardation parachute. It was released above 34,000 ft. and fell for 188 seconds, allowing the aircraft time to reach a safe distance (~30 miles).
The 50-Megaton blast was more than 3,300 times as powerful as the 15-kiloton atomic bomb that destroyed Hiroshima. It was 10 times more powerful than _all_ of the conventional munitions used in World War II. Although skies were cloudy, the flash was visible 621 miles away.