Operation Hardtack II

Operation Hardtack II
Hardtack II Sanford, 4.9 kilotons.
Information
CountryUnited States
Test site
  • NTS Area 12, Rainier Mesa
  • NTS Areas 5, 11, Frenchman Flat
  • NTS, Areas 1–4, 6–10, Yucca Flat
Period1958
Number of tests37
Test typeballoon, dry surface, tower, underground shaft, tunnel
Max. yield22 kilotonnes of TNT (92 TJ)
Test series chronology

Operation Hardtack II[1] was a series of 37 nuclear tests conducted by the United States in 1958 at the Nevada Test Site. These tests followed the Operation Argus series and preceded the Operation Nougat series.

With test moratoriums on the horizon, American weapons labs rushed out many new designs. A hard deadline for testing was set at midnight (0000 hrs), October 31, 1958, as negotiations were set to start that day, and the schedule shows it, with 29 tests executed in October, four of them on the last day. One other test was cancelled because weather delays postponed it across the midnight deadline. After the conclusion of Hardtack II, the United States announced a unilateral testing moratorium, which the Soviet Union joined after two last tests on November 1 and 3.[2] In September 1961, the Soviet Union resumed nuclear testing — including the test of the most powerful nuclear device ever designed, the Tsar Bomba, in October — and the United States followed suit with Operation Nougat.

Nuclear tests

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Adams

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Adams was planned to be the final test of Hardtack II, but due to unfavorable winds the shot was never fired. The shot was intended to be a balloon test, and had been fully assembled and raised to firing altitude when it was cancelled. After midnight and the start of the moratorium, the device was lowered to the ground and disassembled. The Soviet Union would continue nuclear testing until the 3rd of November.[3]

A 31st October 1958 meeting of the Atomic Energy Commission following the cancellation resulted in the following note:[4]

[​General Alfred Starbird​] said there will always be a question as to whether the final shot should have been fired in view of its importance [redacted] but he believed that the other considerations were of overriding importance.

List of nuclear tests

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United States' Hardtack II series tests and detonations
Name [note 1] Date time (UT) Local time zone[note 2][5] Location[note 3] Elevation + height [note 4] Delivery [note 5]
Purpose [note 6]
Device[note 7] Yield[note 8] Fallout[note 9] References Notes
Otero September 12, 1958 20:00:00.2 PST (–8 hrs) NTS Area U3q 37°02′59″N 116°01′57″W / 37.04985°N 116.03255°W / 37.04985; -116.03255 (Otero) 1,229 m (4,032 ft)–150 m (490 ft) underground shaft,
safety experiment
XW-54 ? 38 t Venting detected, 6 kCi (220 TBq) [1][6][7][8] 1-point test, failed, device similar to HT-I Sequoia.
Bernalillo September 17, 1958 19:30:00.2 PST (–8 hrs) NTS Area U3h (n?) 37°02′58″N 116°02′01″W / 37.04944°N 116.03352°W / 37.04944; -116.03352 (Bernalillo) 1,229 m (4,032 ft)–150 m (490 ft) underground shaft,
safety experiment
XW-54 15 t Venting detected on site [1][6][8] 1-point test, repeat of Otero, also failed.
Eddy September 19, 1958 14:00:00.2 PST (–8 hrs) NTS Area B7b ~ 37°05′12″N 116°01′28″W / 37.0866°N 116.0245°W / 37.0866; -116.0245 (Eddy) 1,282 m (4,206 ft) + 150 m (490 ft) balloon,
weapons development
83 t Venting detected, 12 kCi (440 TBq) [1][6][8] 154 pounds (70 kg) test device successful.
Luna September 21, 1958 19:00:00.2 PST (–8 hrs) NTS Area U3m 37°02′57″N 116°02′04″W / 37.04919°N 116.03447°W / 37.04919; -116.03447 (Luna) 1,230 m (4,040 ft)–150 m (490 ft) underground shaft,
safety experiment
XW-54 ? 1.5 t Venting detected on site [1][6][7][8] 1-point test, repeat of Otero/Bernalillo, still unsafe.
Mercury September 23, 1958 22:00:00.0 PST (–8 hrs) NTS Area U12f.01 37°11′34″N 116°12′01″W / 37.19274°N 116.20024°W / 37.19274; -116.20024 (Mercury) 2,038 m (6,686 ft)–55.78 m (183.0 ft) tunnel,
safety experiment
XW-47 primary ? 10 t [1][6][7][8][9] 1-point test, declared success despite yield, XW-42 test, similar to Pascal-C and San Juan devices.
Valencia September 26, 1958 20:00:00.2 PST (–8 hrs) NTS Area U3r 37°02′58″N 116°01′50″W / 37.04956°N 116.03057°W / 37.04956; -116.03057 (Valencia) 1,227 m (4,026 ft)–150 m (490 ft) underground shaft,
safety experiment
XW-42 ? 2 t Venting detected on site [1][6][7][8] 1-point test, declared success despite yield, similar to Pascal-C and San Juan devices.
Mars September 28, 1958 00:00:00.2 PST (–8 hrs) NTS Area U12f.02 37°11′35″N 116°12′05″W / 37.19301°N 116.20131°W / 37.19301; -116.20131 (Mars) 2,082 m (6,831 ft)–42.67 m (140.0 ft) tunnel,
safety experiment
XW-48 13 t Venting detected on site [1][6][7][8][9] 1-point test, similar to Tamalpais and Ceres.
Mora September 29, 1958 14:05:00.1 PST (–8 hrs) NTS Area B7b ~ 37°05′12″N 116°01′28″W / 37.0866°N 116.0245°W / 37.0866; -116.0245 (Mora) 1,282 m (4,206 ft) + 460 m (1,510 ft) balloon,
weapons development
XW-54 Gnat 2 kt Venting detected, 340 kCi (13,000 TBq) [1][6][8] Full yield test of device similar to Otero et al., fizzled.
Hidalgo October 5, 1958 14:10:00.1 PST (–8 hrs) NTS Area B7b ~ 37°05′12″N 116°01′28″W / 37.0866°N 116.0245°W / 37.0866; -116.0245 (Hidalgo) 1,282 m (4,206 ft) + 110 m (360 ft) balloon,
safety experiment
Moccasin 77 t Venting detected, 11 kCi (410 TBq) [1][6][8] This 1-point test failed; similar to Coulomb-C.
Colfax October 5, 1958 16:15:00.2 PST (–8 hrs) NTS Area U3k 37°02′56″N 116°02′06″W / 37.04882°N 116.03491°W / 37.04882; -116.03491 (Colfax) 1,229 m (4,032 ft)–107 m (351 ft) underground shaft,
safety experiment
XW-54 Gnat 5.5 t Venting detected, 240 kCi (8,900 TBq) [1][6][8] 1-point test of device similar to Otero et al., failed. Unstemmed shaft.
Tamalpais October 8, 1958 22:00:00.13 PST (–8 hrs) NTS Area U12b.02 37°11′43″N 116°12′05″W / 37.19525°N 116.20133°W / 37.19525; -116.20133 (Tamalpais) 2,152 m (7,060 ft)–124.05 m (407.0 ft) tunnel,
weapons development
XW-48 72 t [1][6][7][8][9] Full yield test, similar to Mars and Ceres.
Quay October 10, 1958 14:30:00.1 PST (–8 hrs) NTS Area 7c 37°05′41″N 116°01′28″W / 37.0947°N 116.0245°W / 37.0947; -116.0245 (Quay) 1,294 m (4,245 ft) + 30 m (98 ft) tower,
weapons development
XW-50 ? 79 t Venting detected, 200 Ci (7,400 GBq) [1][6][7][8] Concept feasibility test, similar to HT-I Linden.
Lea October 13, 1958 13:20:00.1 PST (–8 hrs) NTS Area B7b ~ 37°05′12″N 116°01′28″W / 37.0866°N 116.0245°W / 37.0866; -116.0245 (Lea) 1,282 m (4,206 ft) + 460 m (1,510 ft) balloon,
weapons development
XW-54 Gnat ? 1.4 kt Venting detected, 240 kCi (8,900 TBq) [1][6][7][8][10] Full yield test of device similar to Otero et al., fizzled.
Neptune October 14, 1958 18:00:00.2 PST (–8 hrs) NTS Area U12c.03 37°11′38″N 116°12′02″W / 37.19381°N 116.20057°W / 37.19381; -116.20057 (Neptune) 2,080 m (6,820 ft)–30.02 m (98.5 ft) tunnel,
safety experiment
XW-47 115 t Venting detected on site [1][6][8][9] 1-point test, failed, similar to HT-I Hickory and HT-II Titania. First NTS subsidence crater at Rainier despite low yield and depth buried.
Hamilton October 15, 1958 16:00:00.2 PST (–8 hrs) NTS Area 5 36°48′08″N 115°55′59″W / 36.8022°N 115.9331°W / 36.8022; -115.9331 (Hamilton) 940 m (3,080 ft) + 15 m (49 ft) tower,
weapons development
XW-51 ? Quail 1.2 t Venting detected, 200 Ci (7,400 GBq) [1][6][7][8] Davy Crockett prototype test, fizzled, extremely small device (16 kg (35 lb)).
Logan October 16, 1958 06:00:00.14 PST (–8 hrs) NTS Area A12e.02 37°11′02″N 116°12′07″W / 37.18399°N 116.20206°W / 37.18399; -116.20206 (Logan) 2,155 m (7,070 ft)–283.58 m (930.4 ft) tunnel,
weapons development
5 kt [1][6][8][9] ABM warhead test, small (28.6 kg (63 lb), 28 cm × 29 cm (11 in × 11 in)) kiloton-range device, successful.
Dona Ana October 16, 1958 14:20:00.1 PST (–8 hrs) NTS Area B7b ~ 37°05′12″N 116°01′28″W / 37.0866°N 116.0245°W / 37.0866; -116.0245 (Dona Ana) 1,282 m (4,206 ft) + 150 m (490 ft) balloon,
weapons development
XW-54 Gnat 37 t Venting detected, 6 kCi (220 TBq) [1][6][8] Low yield test, similar to Otero et al.
Vesta October 17, 1958 23:00:00.2 PST (–8 hrs) NTS Area S9e 37°07′21″N 116°02′05″W / 37.1226°N 116.0347°W / 37.1226; -116.0347 (Vesta) 1,294 m (4,245 ft) + 0 dry surface,
safety experiment
XW-47 primary 24 t Venting detected, 4 kCi (150 TBq) [1][6][7][8] 1-point test, failed, similar to Wrangell, Oberon, Sanford.
Rio Arriba October 18, 1958 14:25:00.1 PST (–8 hrs) NTS Area 3s 37°02′28″N 116°01′36″W / 37.0411°N 116.0267°W / 37.0411; -116.0267 (Rio Arriba) 1,224 m (4,016 ft) + 20 m (66 ft) tower,
weapons development
Mk-7 90 t Venting detected, 120 kCi (4,400 TBq) [1][6][7][8] Low yield Mk-7, successful, fired on wooden tower.
San Juan October 20, 1958 14:30:00.2 PST (–8 hrs) NTS Area U3p 37°02′59″N 116°02′00″W / 37.04976°N 116.03325°W / 37.04976; -116.03325 (San Juan) 1,229 m (4,032 ft)–71 m (233 ft) underground shaft,
safety experiment
XW-42 ? no yield [1][6][7][8] 1-point test, successful, safe design extrapolated from Pascal-C and HT-II Valencia. Unstemmed shaft.
Socorro October 22, 1958 13:30:00.2 PST (–8 hrs) NTS Area B7b ~ 37°05′12″N 116°01′28″W / 37.0866°N 116.0245°W / 37.0866; -116.0245 (Socorro) 1,282 m (4,206 ft) + 440 m (1,440 ft) balloon,
weapons development
XW-54 Gnat ? 6 kt Venting detected, 1,000 kCi (37,000 TBq) [1][6][7][8][10] Full yield test of XW-54 primary, successful, similar to Otero et al.
Wrangell October 22, 1958 16:50:00.1 PST (–8 hrs) NTS Area 5 36°47′53″N 115°55′47″W / 36.798°N 115.9298°W / 36.798; -115.9298 (Wrangell) 940 m (3,080 ft) + 460 m (1,510 ft) balloon,
weapons development
XW-47 Canary ? 115 t Venting detected, 17 kCi (630 TBq) [1][6][7][8] Full yield test fizzle, similar to Vesta, Oberon, Sanford.
Oberon October 22, 1958 20:30:?? PST (–8 hrs) NTS Area 8a 37°10′58″N 116°04′09″W / 37.1829°N 116.0691°W / 37.1829; -116.0691 (Oberon) 1,355 m (4,446 ft) + 8 m (26 ft) tower,
safety experiment
XW-47 primary Canary ? no yield Venting detected, 17 kCi (630 TBq) [1][6][7][8][11] 1-point test, successful, similar to Vesta, Wrangell, Sanford.
Rushmore October 22, 1958 23:40:00.1 PST (–8 hrs) NTS Area B9a ~ 37°08′05″N 116°02′30″W / 37.1347°N 116.0417°W / 37.1347; -116.0417 (Rushmore) 1,285 m (4,216 ft) + 150 m (490 ft) balloon,
weapons development
XW-47 primary Canary ? 188 t [1][6][7][8] Low yield test, fizzled, similar to Mercury, Neptune, Titania.
Catron October 24, 1958 15:00:00.2 PST (–8 hrs) NTS Area 3t 37°02′34″N 116°01′40″W / 37.0427°N 116.0277°W / 37.0427; -116.0277 (Catron) 1,225 m (4,019 ft) + 20 m (66 ft) tower,
safety experiment
XW-54 Gnat 21 t Venting detected, 4 kCi (150 TBq) [1][6][8] 1-point test, similar to Mora, failed, fired on wooden tower.
Juno October 24, 1958 16:01:00.2 PST (–8 hrs) NTS Area S9f 37°07′25″N 116°02′16″W / 37.12361°N 116.03776°W / 37.12361; -116.03776 (Juno) 1,287 m (4,222 ft) + 0 dry surface,
safety experiment
Logan 1.7 t [1][6][7][8] 1-point test to determine safety limits.
Ceres October 26, 1958 04:00:00.2 PST (–8 hrs) NTS Area 8b 37°10′53″N 116°04′09″W / 37.1814°N 116.0691°W / 37.1814; -116.0691 (Ceres) 1,350 m (4,430 ft) + 10 m (33 ft) tower,
safety experiment
XW-48 AFAP 700 kg [1][6][7][8] 1-point test of atomic artillery shell, similar to Tamalpais and Mars.
Sanford October 26, 1958 10:20:00.1 PST (–8 hrs) NTS Area 5 36°47′53″N 115°55′47″W / 36.798°N 115.9298°W / 36.798; -115.9298 (Sanford) 940 m (3,080 ft) + 460 m (1,510 ft) balloon,
weapons development
XW-47 primary Canary ? 4.9 kt Venting detected, 750 kCi (28,000 TBq) [1][6][7][8] Full yield test, successful, similar to Vesta, Oberon, Wrangell.
De Baca October 26, 1958 16:00:00.1 PST (–8 hrs) NTS Area B7b ~ 37°05′12″N 116°01′28″W / 37.0866°N 116.0245°W / 37.0866; -116.0245 (De Baca) 1,282 m (4,206 ft) + 460 m (1,510 ft) balloon,
weapons development
XW-54 Gnat 2.2 kt Venting detected, 380 kCi (14,000 TBq) [1][6][8][10] Full yield test, disappointing yield, similar to Catron and Mora.
Chavez October 27, 1958 14:30:?? PST (–8 hrs) NTS Area 3u 37°02′39″N 116°01′50″W / 37.0443°N 116.0305°W / 37.0443; -116.0305 (Chavez) 1,225 m (4,019 ft) + 16 m (52 ft) tower,
safety experiment
XW-54 Gnat 600 kg Venting detected, 100 Ci (3,700 GBq) [1][6][7][8][11] 1-point test of device similar to De Baca, failed, fired on wooden tower.
Evans October 29, 1958 00:00:00.15 PST (–8 hrs) NTS Area U12b.04 37°11′41″N 116°12′20″W / 37.19477°N 116.20563°W / 37.19477; -116.20563 (Evans) 2,282 m (7,487 ft)–256.03 m (840.0 ft) tunnel,
weapons development
XW-47 primary Canary ? 55 t Venting detected on site [1][6][7][8][9] Full yield test fizzle, similar to Blanca.
Mazama October 29, 1958 11:20:?? PST (–8 hrs) NTS Area 9 37°07′35″N 116°02′31″W / 37.12648°N 116.04196°W / 37.12648; -116.04196 (Mazama) 1,282 m (4,206 ft) + 15 m (49 ft) tower,
weapons development
no yield [1][6][7][8][11] Fizzle.
Humboldt October 29, 1958 14:45:00.1 PST (–8 hrs) NTS Area 3v 37°02′52″N 116°01′32″W / 37.0477°N 116.0256°W / 37.0477; -116.0256 (Humboldt) 1,228 m (4,029 ft) + 10 m (33 ft) tower,
weapons development
XW-51 ? 7.8 t Venting detected, 1 kCi (37 TBq) [1][6][7][8] Repeat of Hamilton with higher yield, extremely small device (16 kg).
Santa Fe October 30, 1958 03:00:00.1 PST (–8 hrs) NTS Area B7b ~ 37°05′12″N 116°01′28″W / 37.0866°N 116.0245°W / 37.0866; -116.0245 (Santa Fe) 1,282 m (4,206 ft) + 460 m (1,510 ft) balloon,
weapons development
XW-54 Gnat 1.3 kt Venting detected, 220 kCi (8,100 TBq) [1][6][8][10] Similar to devices fired in many preceding shots, yield below predictions.
Ganymede October 30, 1958 11:00:?? PST (–8 hrs) NTS Area S9g 37°07′23″N 116°02′06″W / 37.123°N 116.035°W / 37.123; -116.035 (Ganymede) 1,294 m (4,245 ft) + 0 dry surface,
safety experiment
W-45 no yield [1][6][7][8][11] 1-point test of W-45/Swan variant, successful.
Blanca October 30, 1958 15:00:00.15 PST (–8 hrs) NTS Area U12e.05 37°11′09″N 116°12′10″W / 37.18589°N 116.20289°W / 37.18589; -116.20289 (Blanca) 2,168 m (7,113 ft)–254.51 m (835.0 ft) tunnel,
weapons development
XW-47 primary Canary 22 kt Venting detected, 510 Ci (19,000 GBq) [1][6][7][8][9][10] Test of alternate W-47 primary in TN mockup, successful, similar to Evans, shot vented to atmosphere through the side of the mesa.
Titania October 30, 1958 20:34:00.2 PST (–8 hrs) NTS Area 8c 37°10′38″N 116°04′12″W / 37.1773°N 116.0699°W / 37.1773; -116.0699 (Titania) 1,343 m (4,406 ft) + 10 m (33 ft) tower,
safety experiment
XW-47 primary Canary 200 kg [1][6][7][8] 1-point test of original XW-47 primary, declared safe despite yield, similar to HT-I Hickory and HT-II Neptune.
Adams
(canceled)
October 31, 1958 PST (–8 hrs) NTS ~ 37°02′38″N 116°04′05″W / 37.044°N 116.068°W / 37.044; -116.068 (Adams) 1,220 m (4,000 ft) + ??? Balloon,
weapons development
unknown yield Test planned for Hardtack II, but held up by atmospherics that would have shattered windows in Las Vegas, and could not be completed in time before start of moratorium negotiations.
  1. ^ The US, France and Great Britain have code-named their test events, while the USSR and China did not, and therefore have only test numbers (with some exceptions – Soviet peaceful explosions were named). Word translations into English in parentheses unless the name is a proper noun. A dash followed by a number indicates a member of a salvo event. The US also sometimes named the individual explosions in such a salvo test, which results in "name1 – 1(with name2)". If test is canceled or aborted, then the row data like date and location discloses the intended plans, where known.
  2. ^ To convert the UT time into standard local, add the number of hours in parentheses to the UT time; for local daylight saving time, add one additional hour. If the result is earlier than 00:00, add 24 hours and subtract 1 from the day; if it is 24:00 or later, subtract 24 hours and add 1 to the day. Historical time zone data obtained from the IANA time zone database.
  3. ^ Rough place name and a latitude/longitude reference; for rocket-carried tests, the launch location is specified before the detonation location, if known. Some locations are extremely accurate; others (like airdrops and space blasts) may be quite inaccurate. "~" indicates a likely pro-forma rough location, shared with other tests in that same area.
  4. ^ Elevation is the ground level at the point directly below the explosion relative to sea level; height is the additional distance added or subtracted by tower, balloon, shaft, tunnel, air drop or other contrivance. For rocket bursts the ground level is "N/A". In some cases it is not clear if the height is absolute or relative to ground, for example, Plumbbob/John. No number or units indicates the value is unknown, while "0" means zero. Sorting on this column is by elevation and height added together.
  5. ^ Atmospheric, airdrop, balloon, gun, cruise missile, rocket, surface, tower, and barge are all disallowed by the Partial Nuclear Test Ban Treaty. Sealed shaft and tunnel are underground, and remained useful under the PTBT. Intentional cratering tests are borderline; they occurred under the treaty, were sometimes protested, and generally overlooked if the test was declared to be a peaceful use.
  6. ^ Include weapons development, weapon effects, safety test, transport safety test, war, science, joint verification and industrial/peaceful, which may be further broken down.
  7. ^ Designations for test items where known, "?" indicates some uncertainty about the preceding value, nicknames for particular devices in quotes. This category of information is often not officially disclosed.
  8. ^ Estimated energy yield in tons, kilotons, and megatons. A ton of TNT equivalent is defined as 4.184 gigajoules (1 gigacalorie).
  9. ^ Radioactive emission to the atmosphere aside from prompt neutrons, where known. The measured species is only iodine-131 if mentioned, otherwise it is all species. No entry means unknown, probably none if underground and "all" if not; otherwise notation for whether measured on the site only or off the site, where known, and the measured amount of radioactivity released.

References

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  1. ^ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae af ag ah ai aj ak al Yang, Xiaoping; North, Robert; Romney, Carl (August 2000), CMR Nuclear Explosion Database (Revision 3), SMDC Monitoring Research
  2. ^ "Gallery of U.S. Nuclear Tests".
  3. ^ Meade, Roger Allen (September 12, 2022). Hardtack II (Report). Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Retrieved January 23, 2024.
  4. ^ William E Ogle (October 1985). An Account of the Return to Nuclear Weapons Testing by the United States After the Test Moratorium 1958-1961 (Report). US Department of Energy (USDOE), Nevada Operations Office. p. 107-108. Retrieved July 16, 2021.
  5. ^ "Time Zone Historical Database". iana.com. Retrieved March 8, 2014.
  6. ^ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae af ag ah ai aj ak Estimated exposures and thyroid doses received by the American people from Iodine-131 in fallout following Nevada atmospheric nuclear bomb tests, Chapter 2 (PDF), National Cancer Institute, 1997, retrieved January 5, 2014
  7. ^ a b c d e f g h i j k l m n o p q r s t u v w x y z Hansen, Chuck (1995), The Swords of Armageddon, Vol. 8, Sunnyvale, CA: Chukelea Publications, ISBN 978-0-9791915-1-0
  8. ^ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae af ag ah ai aj ak United States Nuclear Tests: July 1945 through September 1992 (PDF) (DOE/NV-209 REV15), Las Vegas, NV: Department of Energy, Nevada Operations Office, December 1, 2000, archived from the original (PDF) on October 12, 2006, retrieved December 18, 2013
  9. ^ a b c d e f g Official list of underground nuclear explosions, Sandia National Laboratories, July 1, 1994, retrieved December 18, 2013
  10. ^ a b c d e Sublette, Carey, Nuclear Weapons Archive, retrieved January 6, 2014
  11. ^ a b c d Operation Hardtack II, 1958 (PDF) (DNA6026F), Defense Nuclear Agency, Department of Defense (Washington, DC), archived from the original (PDF) on February 18, 2013, retrieved October 31, 2013
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