Operation Hardtack II

Operation Hardtack II<ref name=LT_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), 31 October 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 1 and 3 November.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> 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

Tamalpais

The Tamalpais test was conducted in the U12b.02 adit of Rainier Mesa by Lawrence Radiation Laboratory on October 8, 1958.<ref name="LT_6" /> The shot took place in a 394-foot-long hook-shaped drift ending in an unusually large test chamber lined with salt blocks as part of an experiment in preparation for Project Gnome.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref name="Holmes & Narver report">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Additional experiments included measuring permanent tunnel displacement, seismic ground shock measurement, gas sampling by Oak Ridge National Laboratory, and electromagnetic pulse measurement by the Department of Defense Effects Test Group.Template:R<ref name="DNA report">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref name="ORNL gas sampling">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> The detonation of the .072 kiloton device released significant radioactive contamination and damage to the U12 tunnel complex, with radiation levels of 50R/h at the main portal and in the 10,000 R/h range in the tunnel immediately following detonation.<ref name="DNA report" /><ref name="Caging the Dragon">Template:Cite book</ref>Template:Rp The following day, workers reentered the tunnel and triggered a significant hydrogen gas explosion that further damaged the tunnel and injured three workers. Following the tunnel's evacuation, a second hydrogen explosion occurred later the same day.<ref name="Holmes & Narver report" /><ref name="Caging the Dragon" />Template:Rp

Adams

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 3 November.<ref>Template:Cite report</ref>

A 31 October 1958 meeting of the Atomic Energy Commission following the cancellation resulted in the following note:<ref>Template:Cite report</ref>

[[[:Template:Zwsp]]General Alfred StarbirdTemplate:Zwsp] 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.{{#if:|{{#if:|}}

— {{#if:|, in }}Template:Comma separated entries

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List of nuclear tests

United States' Hardtack II series tests and detonations

Name <ref group=note>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.</ref>	Date time (UT)	Local time zone<ref group=note>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.</ref><ref>{{#invoke:citation/CS1|citation	CitationClass=web }}</ref>	Location<ref group=note>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.</ref>	Elevation + height <ref group=note>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.</ref>	Delivery <ref group=note>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.</ref> Purpose <ref group=note>Include weapons development, weapon effects, safety test, transport safety test, war, science, joint verification and industrial/peaceful, which may be further broken down.</ref>	Device<ref group=note>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.</ref>	Yield<ref group=note>Estimated energy yield in tons, kilotons, and megatons. A ton of TNT equivalent is defined as 4.184 gigajoules (1 gigacalorie).</ref>	Fallout<ref group=note>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.</ref>	References	Notes
OteroTemplate:Anchor	Template:Dts 20:00:00.2	PST (–8 hrs)	NTS Area U3q Template:Coord	Template:SortTemplate:Convert–Template:Convert	underground shaft, safety experiment	XW-54 ?	Template:Sort	Venting detected, Template:Convert	<ref name=LT_1 /><ref name=LT_150 /><ref name=LT_24 /><ref name=LT_6 />	1-point test, failed, device similar to HT-I Sequoia.
BernalilloTemplate:Anchor	Template:Dts 19:30:00.2	PST (–8 hrs)	NTS Area U3h (n?) Template:Coord	Template:SortTemplate:Convert–Template:Convert	underground shaft, safety experiment	XW-54	Template:Sort	Venting detected on site	<ref name=LT_1 /><ref name=LT_150 /><ref name=LT_6 />	1-point test, repeat of Otero, also failed.
EddyTemplate:Anchor	Template:Dts 14:00:00.2	PST (–8 hrs)	NTS Area B7b ~ Template:Coord	Template:SortTemplate:Convert + Template:Convert	balloon, weapons development		Template:Sort	Venting detected, Template:Convert	<ref name=LT_1 /><ref name=LT_150 /><ref name=LT_6 />	Template:Convert test device successful.
LunaTemplate:Anchor	Template:Dts 19:00:00.2	PST (–8 hrs)	NTS Area U3m Template:Coord	Template:SortTemplate:Convert–Template:Convert	underground shaft, safety experiment	XW-54 ?	Template:Sort	Venting detected on site	<ref name=LT_1 /><ref name=LT_150 /><ref name=LT_24 /><ref name=LT_6 />	1-point test, repeat of Otero/Bernalillo, still unsafe.
MercuryTemplate:Anchor	Template:Dts 22:00:00.0	PST (–8 hrs)	NTS Area U12f.01 Template:Coord	Template:SortTemplate:Convert–Template:Convert	tunnel, safety experiment	XW-47 primary ?	Template:Sort		<ref name=LT_1 /><ref name=LT_150 /><ref name=LT_24 /><ref name=LT_6 /><ref name=LT_34 />	1-point test, declared success despite yield, XW-42 test, similar to Pascal-C and San Juan devices.
ValenciaTemplate:Anchor	Template:Dts 20:00:00.2	PST (–8 hrs)	NTS Area U3r Template:Coord	Template:SortTemplate:Convert–Template:Convert	underground shaft, safety experiment	XW-42 ?	Template:Sort	Venting detected on site	<ref name=LT_1 /><ref name=LT_150 /><ref name=LT_24 /><ref name=LT_6 />	1-point test, declared success despite yield, similar to Pascal-C and San Juan devices.
MarsTemplate:Anchor	Template:Dts 00:00:00.2	PST (–8 hrs)	NTS Area U12f.02 Template:Coord	Template:SortTemplate:Convert–Template:Convert	tunnel, safety experiment	XW-48	Template:Sort	Venting detected on site	<ref name=LT_1 /><ref name=LT_150 /><ref name=LT_24 /><ref name=LT_6 /><ref name=LT_34 />	1-point test, similar to Tamalpais and Ceres.
MoraTemplate:Anchor	Template:Dts 14:05:00.1	PST (–8 hrs)	NTS Area B7b ~ Template:Coord	Template:SortTemplate:Convert + Template:Convert	balloon, weapons development	XW-54 Gnat	Template:Sort	Venting detected, Template:Convert	<ref name=LT_1 /><ref name=LT_150 /><ref name=LT_6 />	Full yield test of device similar to Otero et al., fizzled.
HidalgoTemplate:Anchor	Template:Dts 14:10:00.1	PST (–8 hrs)	NTS Area B7b ~ Template:Coord	Template:SortTemplate:Convert + Template:Convert	balloon, safety experiment	Moccasin	Template:Sort	Venting detected, Template:Convert	<ref name=LT_1 /><ref name=LT_150 /><ref name=LT_6 />	This 1-point test failed; similar to Coulomb-C.
ColfaxTemplate:Anchor	Template:Dts 16:15:00.2	PST (–8 hrs)	NTS Area U3k Template:Coord	Template:SortTemplate:Convert–Template:Convert	underground shaft, safety experiment	XW-54 Gnat	Template:Sort	Venting detected, Template:Convert	<ref name=LT_1 /><ref name=LT_150 /><ref name=LT_6 />	1-point test of device similar to Otero et al., failed. Unstemmed shaft.
TamalpaisTemplate:Anchor	Template:Dts 22:00:00.13	PST (–8 hrs)	NTS Area U12b.02 Template:Coord	Template:SortTemplate:Convert–Template:Convert	tunnel, weapons development	XW-48	Template:Sort		<ref name=LT_1 /><ref name=LT_150 /><ref name=LT_24 /><ref name=LT_6 /><ref name=LT_34 />	Full yield test, similar to Mars and Ceres.
QuayTemplate:Anchor	Template:Dts 14:30:00.1	PST (–8 hrs)	NTS Area 7c Template:Coord	Template:SortTemplate:Convert + Template:Convert	tower, weapons development	XW-50 ?	Template:Sort	Venting detected, Template:Convert	<ref name=LT_1 /><ref name=LT_150 /><ref name=LT_24 /><ref name=LT_6 />	Concept feasibility test, similar to HT-I Linden.
LeaTemplate:Anchor	Template:Dts 13:20:00.1	PST (–8 hrs)	NTS Area B7b ~ Template:Coord	Template:SortTemplate:Convert + Template:Convert	balloon, weapons development	XW-54 Gnat ?	Template:Sort	Venting detected, Template:Convert	<ref name=LT_1 /><ref name=LT_150 /><ref name=LT_24 /><ref name=LT_6 /><ref name=LT_148 />	Full yield test of device similar to Otero et al., fizzled.
NeptuneTemplate:Anchor	Template:Dts 18:00:00.2	PST (–8 hrs)	NTS Area U12c.03 Template:Coord	Template:SortTemplate:Convert–Template:Convert	tunnel, safety experiment	XW-47	Template:Sort	Venting detected on site	<ref name=LT_1 /><ref name=LT_150 /><ref name=LT_6 /><ref name=LT_34 />	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.
HamiltonTemplate:Anchor	Template:Dts 16:00:00.2	PST (–8 hrs)	NTS Area 5 Template:Coord	Template:SortTemplate:Convert + Template:Convert	tower, weapons development	XW-51 ? Quail	Template:Sort	Venting detected, Template:Convert	<ref name=LT_1 /><ref name=LT_150 /><ref name=LT_24 /><ref name=LT_6 />	Davy Crockett prototype test, fizzled, extremely small device (Template:Convert).
LoganTemplate:Anchor	Template:Dts 06:00:00.14	PST (–8 hrs)	NTS Area A12e.02 Template:Coord	Template:SortTemplate:Convert–Template:Convert	tunnel, weapons development		Template:Sort		<ref name=LT_1 /><ref name=LT_150 /><ref name=LT_6 /><ref name=LT_34 />	ABM warhead test, small (Template:Convert, Template:Convert) kiloton-range device, successful.
Dona AnaTemplate:Anchor	Template:Dts 14:20:00.1	PST (–8 hrs)	NTS Area B7b ~ Template:Coord	Template:SortTemplate:Convert + Template:Convert	balloon, weapons development	XW-54 Gnat	Template:Sort	Venting detected, Template:Convert	<ref name=LT_1 /><ref name=LT_150 /><ref name=LT_6 />	Low yield test, similar to Otero et al.
VestaTemplate:Anchor	Template:Dts 23:00:00.2	PST (–8 hrs)	NTS Area S9e Template:Coord	Template:SortTemplate:Convert + 0	dry surface, safety experiment	XW-47 primary	Template:Sort	Venting detected, Template:Convert	<ref name=LT_1 /><ref name=LT_150 /><ref name=LT_24 /><ref name=LT_6 />	1-point test, failed, similar to Wrangell, Oberon, Sanford.
Rio ArribaTemplate:Anchor	Template:Dts 14:25:00.1	PST (–8 hrs)	NTS Area 3s Template:Coord	Template:SortTemplate:Convert + Template:Convert	tower, weapons development	Mk-7	Template:Sort	Venting detected, Template:Convert	<ref name=LT_1 /><ref name=LT_150 /><ref name=LT_24 /><ref name=LT_6 />	Low yield Mk-7, successful, fired on wooden tower.
San JuanTemplate:Anchor	Template:Dts 14:30:00.2	PST (–8 hrs)	NTS Area U3p Template:Coord	Template:SortTemplate:Convert–Template:Convert	underground shaft, safety experiment	XW-42 ?	Template:Sort		<ref name=LT_1 /><ref name=LT_150 /><ref name=LT_24 /><ref name=LT_6 />	1-point test, successful, safe design extrapolated from Pascal-C and HT-II Valencia. Unstemmed shaft.
SocorroTemplate:Anchor	Template:Dts 13:30:00.2	PST (–8 hrs)	NTS Area B7b ~ Template:Coord	Template:SortTemplate:Convert + Template:Convert	balloon, weapons development	XW-54 Gnat ?	Template:Sort	Venting detected, Template:Convert	<ref name=LT_1 /><ref name=LT_150 /><ref name=LT_24 /><ref name=LT_6 /><ref name=LT_148 />	Full yield test of XW-54 primary, successful, similar to Otero et al.
WrangellTemplate:Anchor	Template:Dts 16:50:00.1	PST (–8 hrs)	NTS Area 5 Template:Coord	Template:SortTemplate:Convert + Template:Convert	balloon, weapons development	XW-47 Canary ?	Template:Sort	Venting detected, Template:Convert	<ref name=LT_1 /><ref name=LT_150 /><ref name=LT_24 /><ref name=LT_6 />	Full yield test fizzle, similar to Vesta, Oberon, Sanford.
OberonTemplate:Anchor	Template:Dts 20:30:??	PST (–8 hrs)	NTS Area 8a Template:Coord	Template:SortTemplate:Convert + Template:Convert	tower, safety experiment	XW-47 primary Canary ?	Template:Sort	Venting detected, Template:Convert	<ref name=LT_1 /><ref name=LT_150 /><ref name=LT_24 /><ref name=LT_6 /><ref name=LT_163 />	1-point test, successful, similar to Vesta, Wrangell, Sanford.
RushmoreTemplate:Anchor	Template:Dts 23:40:00.1	PST (–8 hrs)	NTS Area B9a ~ Template:Coord	Template:SortTemplate:Convert + Template:Convert	balloon, weapons development	XW-47 primary Canary ?	Template:Sort		<ref name=LT_1 /><ref name=LT_150 /><ref name=LT_24 /><ref name=LT_6 />	Low yield test, fizzled, similar to Mercury, Neptune, Titania.
CatronTemplate:Anchor	Template:Dts 15:00:00.2	PST (–8 hrs)	NTS Area 3t Template:Coord	Template:SortTemplate:Convert + Template:Convert	tower, safety experiment	XW-54 Gnat	Template:Sort	Venting detected, Template:Convert	<ref name=LT_1 /><ref name=LT_150 /><ref name=LT_6 />	1-point test, similar to Mora, failed, fired on wooden tower.
JunoTemplate:Anchor	Template:Dts 16:01:00.2	PST (–8 hrs)	NTS Area S9f Template:Coord	Template:SortTemplate:Convert + 0	dry surface, safety experiment	Logan	Template:Sort		<ref name=LT_1 /><ref name=LT_150 /><ref name=LT_24 /><ref name=LT_6 />	1-point test to determine safety limits.
CeresTemplate:Anchor	Template:Dts 04:00:00.2	PST (–8 hrs)	NTS Area 8b Template:Coord	Template:SortTemplate:Convert + Template:Convert	tower, safety experiment	XW-48 AFAP	Template:Sort		<ref name=LT_1 /><ref name=LT_150 /><ref name=LT_24 /><ref name=LT_6 />	1-point test of atomic artillery shell, similar to Tamalpais and Mars.
SanfordTemplate:Anchor	Template:Dts 10:20:00.1	PST (–8 hrs)	NTS Area 5 Template:Coord	Template:SortTemplate:Convert + Template:Convert	balloon, weapons development	XW-47 primary Canary ?	Template:Sort	Venting detected, Template:Convert	<ref name=LT_1 /><ref name=LT_150 /><ref name=LT_24 /><ref name=LT_6 />	Full yield test, successful, similar to Vesta, Oberon, Wrangell.
De BacaTemplate:Anchor	Template:Dts 16:00:00.1	PST (–8 hrs)	NTS Area B7b ~ Template:Coord	Template:SortTemplate:Convert + Template:Convert	balloon, weapons development	XW-54 Gnat	Template:Sort	Venting detected, Template:Convert	<ref name=LT_1 /><ref name=LT_150 /><ref name=LT_6 /><ref name=LT_148 />	Full yield test, disappointing yield, similar to Catron and Mora.
ChavezTemplate:Anchor	Template:Dts 14:30:??	PST (–8 hrs)	NTS Area 3u Template:Coord	Template:SortTemplate:Convert + Template:Convert	tower, safety experiment	XW-54 Gnat	Template:Sort	Venting detected, Template:Convert	<ref name=LT_1 /><ref name=LT_150 /><ref name=LT_24 /><ref name=LT_6 /><ref name=LT_163 />	1-point test of device similar to De Baca, failed, fired on wooden tower.
EvansTemplate:Anchor	Template:Dts 00:00:00.15	PST (–8 hrs)	NTS Area U12b.04 Template:Coord	Template:SortTemplate:Convert–Template:Convert	tunnel, weapons development	XW-47 primary Canary ?	Template:Sort	Venting detected on site	<ref name=LT_1 /><ref name=LT_150 /><ref name=LT_24 /><ref name=LT_6 /><ref name=LT_34 />	Full yield test fizzle, similar to Blanca.
MazamaTemplate:Anchor	Template:Dts 11:20:??	PST (–8 hrs)	NTS Area 9 Template:Coord	Template:SortTemplate:Convert + Template:Convert	tower, weapons development		Template:Sort		<ref name=LT_1 /><ref name=LT_150 /><ref name=LT_24 /><ref name=LT_6 /><ref name=LT_163 />	Fizzle.
HumboldtTemplate:Anchor	Template:Dts 14:45:00.1	PST (–8 hrs)	NTS Area 3v Template:Coord	Template:SortTemplate:Convert + Template:Convert	tower, weapons development	XW-51 ?	Template:Sort	Venting detected, Template:Convert	<ref name=LT_1 /><ref name=LT_150 /><ref name=LT_24 /><ref name=LT_6 />	Repeat of Hamilton with higher yield, extremely small device (16 kg).
Santa FeTemplate:Anchor	Template:Dts 03:00:00.1	PST (–8 hrs)	NTS Area B7b ~ Template:Coord	Template:SortTemplate:Convert + Template:Convert	balloon, weapons development	XW-54 Gnat	Template:Sort	Venting detected, Template:Convert	<ref name=LT_1 /><ref name=LT_150 /><ref name=LT_6 /><ref name=LT_148 />	Similar to devices fired in many preceding shots, yield below predictions.
GanymedeTemplate:Anchor	Template:Dts 11:00:??	PST (–8 hrs)	NTS Area S9g Template:Coord	Template:SortTemplate:Convert + 0	dry surface, safety experiment	W-45	Template:Sort		<ref name=LT_1 /><ref name=LT_150 /><ref name=LT_24 /><ref name=LT_6 /><ref name=LT_163 />	1-point test of W-45/Swan variant, successful.
BlancaTemplate:Anchor	Template:Dts 15:00:00.15	PST (–8 hrs)	NTS Area U12e.05 Template:Coord	Template:SortTemplate:Convert–Template:Convert	tunnel, weapons development	XW-47 primary Canary	Template:Sort	Venting detected, Template:Convert	<ref name=LT_1 /><ref name=LT_150 /><ref name=LT_24 /><ref name=LT_6 /><ref name=LT_34 /><ref name=LT_148 />	Test of alternate W-47 primary in TN mockup, successful, similar to Evans, shot vented to atmosphere through the side of the mesa.
TitaniaTemplate:Anchor	Template:Dts 20:34:00.2	PST (–8 hrs)	NTS Area 8c Template:Coord	Template:SortTemplate:Convert + Template:Convert	tower, safety experiment	XW-47 primary Canary	Template:Sort		<ref name=LT_1 /><ref name=LT_150 /><ref name=LT_24 /><ref name=LT_6 />	1-point test of original XW-47 primary, declared safe despite yield, similar to HT-I Hickory and HT-II Neptune.
Adams (canceled)Template:Anchor	Template:Dts	PST (–8 hrs)	NTS ~ Template:Coord	Template:SortTemplate:Convert + ???	Balloon, weapons development		Template:Sort			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.

External links

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