Operation Redwing

1956 - Enewetak and Bikini Atolls, Marshall Islands

Lacrosse

LASL test of an externally initiated boosted primary in a thermonuclear system mockup for the TX-39 (a redesign of the Mk-15). The overall device was 34.5 inches in diameter and 100 inches long, weight was 8386 lb., the primary system was 583 lb. Predicted yield was 25-50 kt. This primary was similar to the all oralloy device safety tested in Project 56 #1. This primary was used in the Redwing Apache thermonuclear shot, and was similar to the device later fired in Plumbbob Priscilla.

Crater dimensions were 400 feet wide, 55 feet deep.

Redwing Lacrosse Test Device (38 K)

Cherokee

This was the first U.S. air drop of a thermonuclear weapon. This DOD sponsored test (using an LASL designed device) was intended to gather weapon effects data for high yield air bursts, but also was a political demonstration of the United States capability to deliver H-bombs by air to pressure the Soviet Union.

The weapon used was a TX-15-X1 weapon similar to the lower yield Zombie device tested in Castle Nectar. The B-52 was flown from Fred Island at Eniwetak. The intended ground zero was directly over Namu Island, but the flight crew mistook an observation facility on a different island for their targeting beacon with the result that the weapon delivery was grossly in error. The bomb detonated some 4 miles off target over the ocean northeast of Namu. As a result essentially all of the weapons effects data was lost.

The operational configuration bomb was 34.5 inches wide, 136 inches long, and weighed 6867 lb. The yield was very close to the predicted value. The cloud height rose to 94,000 feet. Although the Mk-15/39 was a radiation implosion design that harnessed thermonuclear reactions, it seems to have been a transitional design that could also be considered a radiation implosion boosted fission design. The secondary consisted of highly enriched uranium jacket that would have produced a high yield fission explosion even without the yield-boosting fusion fuel it contained.

Zuni

The Bassoon device fired in Zuni was the first test ever of a three stage thermonuclear design. Surprisingly, this substantial innovation was also the first successful thermonuclear device design ever fired by Lawrence Livermore (then known as UCRL, now LLNL). The configuration fired in this test was a "clean" (low fallout) version that used a lead tamper around the thermonuclear third stage. Only 15% of the energy yield was from fission. A "dirty" version of this design, the Bassoon Prime device, was later fired in Redwing Tewa. The predicted yield for Zuni was 2-3 Mt.

The Bassoon device was 39 inches in diameter, and 135.5 inches long. It weighed 12,158 lb. Crater dimensions were 2330 feet wide, 113 feet deep.

This design was later developed into the Mk-41 bomb, the highest yield (25 Mt) weapon ever deployed by the U.S.

Redwing Zuni Shot Cab (108 K)

Redwing Zuni Mushroom (43 K)

Redwing Zuni Crater (88 K)

Click here for Zuni fallout map (49 K)

Yuma

This was a UCRL linear implosion design intended for air defense warheads. The device, known as Swift, was a boosted asymmetrical design. The device failed to boost however, and the yield was far below predictions. The Swift was only 5 inches in diameter, and 24.5 inches long, and weighed 96 lb. This was the smallest diameter, and lightest nuclear device tested up to this time. It used Octol 76/24 as the explosive and was presumably a plutonium fueled device.

Erie

This was a test of the boosted primary and the implosion system for the TX-28C ("C" for "clean") thermonuclear bomb. The complete device was 20 inches in diameter, 55 inches long, and weighed 2106 lb. The primary weighed 142.6 lb.

Redwing Erie (80 K)

Seminole

Seminole was one of the most peculiar weapon effects tests ever conducted, as well as one of the most spectacular. This was a combined weapons development/effects test in which the device was exploded in a large tank of water to couple the shock wave to the ground. In effect the above-ground water tank simulated an underground nuclear test. The device was housed in a circular chamber inside the water tank which was accessible by a corridor through the tank. The chamber was 10 feet off center from the tank center, which led to a significant asymmetry in the crater produced. The crater produced was 660 feet wide and 32 feet deep.

The shot was designed so that by the time the fireball reached the wall of the tank, it had transitioned from thermal radiation-driven growth to hydrodynamic (shock wave driven) growth. As can be seen in the images below, the shock wave front of the fireball is still quite luminous.

The device being tested was a TX-28 primary/implosion system. The device was 20 inches in diameter and 55 inches long. The boosted primary had a predicted yield of 10 kt. The total device weight was 1832 lb, the primary itself weighed 143.5 lb.

The Seminole device before detonation:

Seminole Device (39 K)

The shot tank:

Seminole Shot Tank (86 K)

Below are two sets of images. The represent the same picture sequence, but have been processed differently with different field of view, color, contrast, detail, and file size results. Take your pick.

Seminole Fireball	101 K Big version - 151K	54 K
Wilson Effect Cloud	109 K	54 K
Redwing Fallout	146 K	83 K

Black and white fallout picture

Seminole Fallout (30 K)

Seminole fallout from afar:

Seminole in the distance (70 K)

Seminole crater:

Seminole Crater (59 K)

Flathead

This was a test of the TX-28S ("S" for "salted"), a dirty high fallout bomb design. The yield was 73% fission. The device was 20 inches by 55 inches and weighed 1374 lb.

Blackfoot

This LASL test was a prototype of a low-yield, small-diameter, light weight air defense warhead. The boosted device was the first nuclear test ever to use a PBX (plastic bonded explosive) for the implosion system (PBX-9401 and PBX-9404 were used). This device demonstrated what appears to be roughly a minimum diameter spherical implosion system. The device diameter was only 11.5 inches, no other known spherical implosion system appears to have shaved more than an inch from this. The device length was 23 inches, and the nuclear system weighed only 62.7 lb (total device weight was 130 lb.).

Redwing Blackfoot (28 K)

Kickapoo

This was a UCRL linear implosion design intended for air defense warheads. This device, known as Swallow, was a boosted asymmetrical design. The Swallow device was 8 inches in diameter, and 28 inches long, and weighed 225 lb. This was the smallest diameter, and lightest nuclear device tested up to this time. It used Cyclotol 75/25 as the explosive and was presumably a plutonium fueled device.

Osage

Proof test of the LASL XW-25 warhead. This was a light weight, low yield, plutonium warhead intended for air defense and other tactical applications. This spherical implosion device had a diameter of 17.4 inches, was 25.7 inches long and weighed 174.6 lb. It was dropped in an instrumented Mk 7 drop case, which had a total weight of 3150 lb.

Inca

UCRL test of a multi-application boosted tactical nuclear warhead prototype named Swan. This design was later developed into the XW-45 warhead. The predicted yield was 10-15 kt.

Dakota

TX-28C variant prototype test. The W-28 small diameter, light weight ("Class-D") thermonuclear weapon design became the most versatile and widely used design ever adopted by the United States. Entering service in 1958 (the first operational version was manufactured in 1/58), the W-28 remained in service until 1990 (last one dismantled 9/91). It was fielded in 5 models, with 20 variants.

The test device was 20 inches in diameter, 58 inches long, and weighed 1797 lb. This test did substantially better than expected. The predicted yield was 800 kt. Dakota was fired over the Flathead test site.

Redwing Dakota (54 K)

Mohawk

This UCRL thermonuclear device used a boosted "Swan" primary and "Flute" secondary. The device was 15 inches in diameter, 46.2 inches long, and weighed 1116 lb. The primary was 11.6 inches by 22.8 inches and weighed 105 lb. The yield was at the high end of the predicted range. A wide but very shallow crater was created (mostly due to pressure collapse of the porous coral soil) - 1340 feet by 8 feet.

The picture below shows Mohawk several hundred microseconds after detonation. The "pimple" at right is the vaporized shot cab.

Mohawk Early Fireball (71 K)

Mohawk Mushroom (41 K)

Apache

UCRL test of a two-stage system using a Zither secondary stage. This was a prototype of the XW-27 warhead intended for the Regulus I missile and was fired in a Regulus nose cone. Used the same LASL primary design that was fired in Redwing Lacrosse (40 kt). The test device was 30.2 inches in diameter, 69.8 inches long, and weighed 2941 lb. A high percentage of the yield was due to fission.

	Redwing Apache 375x250, 13 K 640x427, 36 K 1024x683, 52 K 1600x1068, 138 K
	Redwing Apache (64 K)
	Redwing Apache (36 K)
	Redwing Apache (38 K)

Navajo

LASL test of the TX-21C "clean" thermonuclear device. The yield was 95% fusion, the highest known fusion yield of any U.S. test (and thus the cleanest U.S. shot ever fired). Yield was in the predicted range.

Tewa

This device, the Bassoon Prime, was a "dirty" three stage design, the first U.S. three stage design. This was actually the second test of this design (the earlier "clean" version, Bassoon, was test fired in Redwing Zuni). The fission yield was 87%, the highest known fission yield in any U.S. thermonuclear test. A uranium tamper was used around the tertiary stage instead of the lead tamper used in Zuni. The predicted yield was 6-8 Mt.

This design was later developed into the Mk-41 bomb, the highest yield (25 Mt) weapon ever deployed by the U.S.

Tewa Before

Shown below is the Bassoon Prime device being installed in its "shot cab". Two diagnostic "light pipes" are visible.
The device is 39 inches in diameter, 135.5 inches long, and weighed 15,735 lbs. The crater left in the reef was 4000 ft in diameter and 129 ft deep.

Bassoon Prime Device (110 K)

This is the Tewa shot barge.

Tewa Shot Barge (47 K)

Tewa Detonation

Redwing Tewa 324x250, 14 K 640x494, 29 K 1024x790, 74 K 1280x988, 191 K 1600x1235, 209 K

Tewa After

The Tewa shot crater.

Tewa Shot Crater (56 K)

Click for Tewa fallout map (452x456, 50 K)

Huron

LASL two stage Egg device, diameter 15.3 inches, length 43.1 inches, weight 793 lb. Used PBX-9401 and PBX-9404 explosives. Matched the predicted yield. Possible XW-50 prototype.

Redwing Shot Schedule, 25 January 1956

Shot Name	Ready Date	Shot Site	Predicted Yield
Lacrosse	May 1	Eniwetok (off Runit), Barge	25-50 kt
Cherokee	May 1	Bikini (Namu), Air Drop, 5000 Ft burst height	-
Zuni	May 15	Bikini (Eninman), Ground	2-3 Mt
Erie	May 23	Eniwetok (Runit), 300 Ft tower burst	-
Seminole	May 28	Eniwetok (Bogon),Ground	10 kt
Yuma	June 1	Eniwetok (Aomon), 200 Ft tower	-
Flathead	June 2	Bikini (Yurochi), Barge	-
Blackfoot	June 7	Eniwetok (Runit), 200 Ft tower	-
Inca	June 8	Eniwetok (Rujoru), 200 Ft tower	10-15 kt
Huron	June 12	Bikini (Yurochi), Barge	-
Osage	June 14	Eniwetok (Runit), Air drop, 700 Ft burst height	-
Kickapoo	June 18	Eniwetok (Aomon), 300 Ft tower	-
Navajo	June 18	Bikini (Yurochi), Barge	-
Mohawk	July 1	Eniwetok (Eberiru), 300 Ft tower	-
Apache	July 1	Bikini (Yurochi), Barge	-
Tewa	July 7	Bikini (Yurochi), Barge	6-8 Mt

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Redwing Shot Results

Shot Name	Firing Time and Date (GMT)	Yield - Actual (Predicted)
Lacrosse	18:25 4 May	40 kt (25-50 kt)
Cherokee	17:51 20 May	3.8 Mt
Zuni	17:56 27 May	3.5 Mt (2-3 Mt)
Yuma	19:56 27 May	0.19 kt
Erie	18:15 30 May	14.9 kt
Seminole	00:55 6 June	13.7 kt (10 kt)
Flathead	18:26 11 June	365 kt
Blackfoot	18:26 11 June	8 kt
Kickapoo	23:26 13 June	1.49 kt
Osage	01:14 16 June	1.7 kt
Inca	21:26 21 June	15.2 kt (10-15 kt)
Dakota	18:06 25 June	1.1 Mt (800 kt)
Mohawk	18:06 2 July	360 kt
Apache	18:06 8 July	1.85 Mt
Navajo	17:56 10 July	4.5 Mt
Tewa	17:46 20 July	5 Mt (6-8 Mt)
Huron	18:12 21 July	250 kt

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