Operation Latchkey Explained

Operation Latchkey
Country:	United States
Test Site:	NTS Area 12, Rainier Mesa NTS Area 19, 20, Pahute Mesa NTS Areas 5, 11, Frenchman Flat NTS, Areas 1–4, 6–10, Yucca Flat Salmon Site, near Lumberton, Mississippi
Period:	1966–1967
Number Of Tests:	38
Test Type:	underground shaft, tunnel
Max Yield:	870ktTNT
Next Series:	Operation Crosstie

Operation Latchkey was a series of 38 nuclear tests conducted by the United States in 1966–1967 at the Nevada Test Site. These tests followed the Operation Flintlock series and preceded the Operation Crosstie series.

Nuclear tests

Persimmon

Persimmon included a vertical line-of-sight pipe fitted with a fast-acting closure. At the time of detonation, this vacuum pipe provided a pathway for neutrons from the nuclear device to travel to instruments in a tower located above the shot hole. A few seconds after detonation, these instruments and their samples were dragged out of the tower on a sled, before the subsidence crater formed and destroyed the tower.^[1]

List of the nuclear tests

United States' Latchkey series tests and detonations
- !style="background:#ffdead;"	Name ^[2] !style="background:#efefef;"	Date time (UT) !style="background:#ffdead;"	Local time zone^[3] ^[4] !style="background:#efefef;"	Location^[5] !style="background:#ffdead;"	Elevation + height ^[6] !style="background:#efefef;"	Delivery ^[7] Purpose ^[8] !style="background:#efefef;"	Device^[9] !style="background:#ffdead;"	Yield^[10] !style="background:#efefef;" class="unsortable"	Fallout^[11] !style="background:#ffdead;" class="unsortable"	References !style="background:#efefef;" class="unsortable"	Notes	- ! Saxon	15:33:30.13	PST (–8 hrs)	NTS Area U2cc 37.1404°N -116.134°W	1411m (4,629feet) – 153.04m (502.1feet)	underground shaft, peaceful research			Venting detected, 0.5Ci		Project Plowshare - excavation device development.	- ! Rovena	13:16:00.07	PST (–8 hrs)	NTS Area U10s 37.1686°N -116.0486°W	1278m (4,193feet) – 195.25m (640.58feet)	underground shaft, weapons development			Venting detected, 2Ci			- ! Tangerine	15:36:00.05	PST (–8 hrs)	NTS Area U3eb 37.0463°N -116.0301°W	1199m (3,934feet) – 87.88m (288.32feet)	underground shaft, safety experiment						- ! Derringer	15:30:00.54	PST (–8 hrs)	NTS Area U5i 36.876°N -115.9514°W	1013m (3,323feet) – 255.12m (837.01feet)	underground shaft, weapon effect			Venting detected off site, 12kCi			- ! Daiquiri	18:00:00.04	PST (–8 hrs)	NTS Area U7o 37.1033°N -116.0366°W	1260m (4,130feet) – 561.15m (1,841.04feet)	underground shaft, weapons development						- ! Newark	14:45:30.09	PST (–8 hrs)	NTS Area U10u 37.1686°N -116.0469°W	1279m (4,196feet) – 228.63m (750.1feet)	underground shaft, weapons development			Venting detected, 290Ci			- ! Khaki	19:00:00.05	PST (–8 hrs)	NTS Area U3et 37.047°N -116.0177°W	1202m (3,944feet) – 232.55m (762.96feet)	underground shaft, weapons development						- ! Simms	14:45:00.0	PST (–8 hrs)	NTS Area U10w 37.1699°N -116.0481°W	1279m (4,196feet) – 198.15m (650.1feet)	underground shaft, peaceful research			Venting detected, 11Ci		Plowshare - evaluate clean nuclear explosives for excavation.	- ! Ajax	12:00:00.14	PST (–8 hrs)	NTS Area U9al 37.1345°N -116.051°W	1254m (4,114feet) – 238.45m (782.32feet)	underground shaft, weapons development			Venting detected on site, 1Ci			- ! Cerise	15:02:00.04	PST (–8 hrs)	NTS Area U3eu 37.0427°N -116.0113°W	1202m (3,944feet) – 211.09m (692.55feet)	underground shaft, weapons development			I-131 venting detected, 0			- ! Vigil	15:00:00.13	PST (–8 hrs)	NTS Area U10ad 37.1693°N -116.0492°W	1278m (4,193feet) – 93.68m (307.35feet)	underground shaft, safety experiment			Venting detected on site, 0.0014Ci			- ! Sterling	12:15:00.05	CST (–6 hrs)	Salmon Site, near Lumberton, Mississippi 31.1423°N -89.57°W	74m (243feet) – 830m (2,720feet)	underground shaft, joint verification					Project Vela Uniform/Dribble. Exploded inside the cavity created by Whetstone/Salmon in Tatum salt dome.	- ! Sidecar	17:50:00.04	PST (–8 hrs)	NTS Area U3ez 37.0348°N -116.0075°W	1195m (3,921feet) – 240.27m (788.29feet)	underground shaft, weapons development			Venting detected on site, 0.041Ci			- ! New Point	21:00:00.08	PST (–8 hrs)	NTS Area U11c 36.8772°N -115.9388°W	1003m (3,291feet) – 243.84m (800feet)	underground shaft, weapon effect			Venting detected on site, 3Ci			- ! Greeley	15:30:00.08	PST (–8 hrs)	NTS Area U20g - 37.3023°N -116.4097°W	1945m (6,381feet) – 1214.63m (3,985.01feet)	underground shaft, weapons development					Test of Spartan warhead (W71).^[12]	- ! Rivet 1	14:55:00.0	PST (–8 hrs)	NTS Area U10aa 37.1651°N -116.0474°W	1276m (4,186feet) – 152.1m (499feet)	underground shaft, weapons development						- ! Nash	16:45:00.14	PST (–8 hrs)	NTS Area U2ce 37.1437°N -116.1362°W	1425m (4,675feet) – 363.78m (1,193.5feet)	underground shaft, weapons development			Venting detected off site, 69kCi			- ! Bourbon	17:40:04.41	PST (–8 hrs)	NTS Area U7n 37.0998°N -116.0047°W	1306m (4,285feet) – 559.72m (1,836.35feet)	underground shaft, weapons development						- ! Rivet 2	16:30:00.0	PST (–8 hrs)	NTS Area U10z 37.1648°N -116.0489°W	1274m (4,180feet) – 197.78m (648.88feet)	underground shaft, weapons development			Venting detected on site, 0.1Ci			- ! Ward	15:15:00.13	PST (–8 hrs)	NTS Area U10x 37.1675°N -116.048°W	1277m (4,190feet) – 257.25m (844feet)	underground shaft, weapons development						- ! Persimmon	18:34:00.04	PST (–8 hrs)	NTS Area U3dn 37.0176°N -116.0166°W	1184m (3,885feet) – 299.11m (981.33feet)	underground shaft, weapons development						- ! Agile	18:50:00.13	PST (–8 hrs)	NTS Area U2v 37.1268°N -116.0673°W	1270m (4,170feet) – 731.52m (2,400feet)	underground shaft, weapons development						- ! Rivet 3	15:00:00.0	PST (–8 hrs)	NTS Area U10y 37.1658°N -116.0496°W	1275m (4,183feet) – 271.27m (889.99feet)	underground shaft, weapons development			Venting detected			- ! Mushroom	15:19:00.04	PST (–8 hrs)	NTS Area U3ef 37.0395°N -116.0109°W	1198m (3,930feet) – 179.55m (589.07feet)	underground shaft, weapons development			Venting detected on site, 0.4Ci			- ! Fizz	15:00:00.04	PST (–8 hrs)	NTS Area U3fr 37.0461°N -116.0307°W	1199m (3,934feet) – 117.73m (386.25feet)	underground shaft, safety experiment						- ! Oakland	14:20:00.15	PST (–8 hrs)	NTS Area U2bi 37.162°N -116.0831°W	1321m (4,334feet) – 165.35m (542.49feet)	underground shaft, weapons development			Venting detected, 100Ci			- ! Heilman	15:00:00.12	PST (–8 hrs)	NTS Area U2cg 37.1373°N -116.1336°W	1405m (4,610feet) – 152.7m (501feet)	underground shaft, weapons development			Venting detected on site, 8Ci			- ! Fawn	15:00:00.04	PST (–8 hrs)	NTS Area U3eo 37.0544°N -116.023°W	1206m (3,957feet) – 271.06m (889.3feet)	underground shaft, weapons development						- ! Chocolate	15:09:00.04	PST (–8 hrs)	NTS Area U3es 37.0193°N -116.0382°W	1186m (3,891feet) – 240.45m (788.88feet)	underground shaft, weapons development						- ! Effendi	14:45:00.0	PST (–8 hrs)	NTS Area U2ap 37.1387°N -116.0641°W	1279m (4,196feet) – 219.29m (719.46feet)	underground shaft, weapons development						- ! Mickey	13:40:00.041	PST (–8 hrs)	NTS Area U7m 37.0778°N -115.9962°W	1278m (4,193feet) – 499.63m (1,639.21feet)	underground shaft, weapons development						- ! Commodore	15:00:00.2	PST (–8 hrs)	NTS Area U2am 37.1301°N -116.0652°W	1271m (4,170feet) – 746.46m (2,449.02feet)	underground shaft, weapons development			Venting detected, less than 1Ci			- ! Scotch	14:00:00.04	PST (–8 hrs)	NTS Area U19as 37.275°N -116.3709°W	2034m (6,673feet) – 977.39m (3,206.66feet)	underground shaft, weapons development						- ! Absinthe	12:30:00.03	PST (–8 hrs)	NTS Area U3ep 37.045°N -116.0198°W	1199m (3,934feet) – 118.65m (389.27feet)	underground shaft, safety experiment						- ! Knickerbocker	15:00:01.5	PST (–8 hrs)	NTS Area U20d 37.2479°N -116.4811°W	1878m (6,161feet) – 630.63m (2,069feet)	underground shaft, weapons development			Venting detected, 110Ci			- ! Switch	13:10:00.0	PST (–8 hrs)	NTS Area U9bv 37.1255°N -116.0295°W	1277m (4,190feet) – 301.75m (989.99feet)	underground shaft, peaceful research			Venting detected off site, less than 1Ci		Project Plowshare - evaluate clean nuclear explosives for excavation.	- ! Midi Mist	16:00:00.08	PST (–8 hrs)	NTS Area U12n.02 37.2021°N -116.2087°W	2200m (7,200feet) – 374.9m (1,230feet)	tunnel, weapon effect			Venting detected, 4.5kCi			- ! Umber	11:25:00.04	PST (–8 hrs)	NTS Area U3em 37.0285°N -116.0233°W	1188m (3,898feet) – 310.24m (1,017.85feet)	underground shaft, weapon effect			Venting detected off site, 26kCi

Notes and References

Los Alamos Scientific Laboratory. Persimmon: A Nuclear Physics Experiment. 2022-09-25. November 9, 2022. https://web.archive.org/web/20221109053437/https://www.youtube.com/watch?v=wXmUVRD_OVk&gl=US&hl=en. live.
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.
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. All historical time zone data are derived from here:
Web site: Time Zone Historical Database. iana.com. March 8, 2014. March 11, 2014. https://web.archive.org/web/20140311224729/http://www.ietf.org/timezones/. live.
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.
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.
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.
Include weapons development, weapon effects, safety test, transport safety test, war, science, joint verification and industrial/peaceful, which may be further broken down.
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.
Estimated energy yield in tons, kilotons, and megatons. A ton of TNT equivalent is defined as 4.184 gigajoules (1 gigacalorie).
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.
Robert McNamara. Production and Deployment of the Nike-X. Secretary of Defense McNamara Memorandum for the President. 2022-06-24. 1966-12-02. 24. January 21, 2022. https://web.archive.org/web/20220121005834/https://nsarchive2.gwu.edu/nukevault/ebb281/4A.pdf. live.