Operation Hardtack II - 1958 Sorocco - 22/10/1958 1958 was a very busy year for nuclear weapons testing by the U.S., with a total of 77 tests, more than the three previous record setting years combined. This burst of testing activity was partly due to building pressure for an imminent test moratorium, leading the weapons labs to rush as many device types to the test range as possible, and partly due to the accelerating momentum of the arms race of the 1950s. 1958 was exceeded only by the 96 tests in 1962, sandwiched as it was between a testing moratorium followed by a surprise moratorium breakout by the Soviet Union in 1961, and the imminent prospect of a permanent atmospheric testing ban. This second phase of Operation Hardtack was originally to be called Millrace. On 29 August 1958, by AEC directive, the name of the continental portion of the test series was changed to Operation Hardtack Phase II. The Los Alamos (LASL) shots had names taken from New Mexico counties. The Livermore (UCRL) shots had names of North American mountains, Roman gods and goddesses, and the fairies of A Mid-Summer Night's Dream. Hardtack II included 37 tests, the largest test series so far, exceeding the 35 tests of the just completed Hardtack I. Hardtack I had focused primarily on high yield proof or developemental tests of complete thermonuclear weapons, which necessitated it be conducted in the distant Pacific. In contrast, Hardtack II consisted exclusively of low yield tests, many of them attempted zero-yield one-point safety tests which could be conducted in relative safety in Nevada. Only 45.8 kt total was fired in Hardtack II, and of this only 18.5 kt was fired above ground. This was a dramatic turnaround from the previous Nevada test series, Plumbbob, in which the above ground Hood shot by itself was 74 kt. Concern about the effects of fallout on the U.S. was certainly making itself felt. Because of the accelerated testing timetable, as many as four detonations were held on one day, and all 37 tests being conducted within just 49 days. De Baca - 26/10/1958 Most of the tests were efforts to prove the safety and effectiveness of new "sealed pit" fission primaries and tactical weapons. This task proved extremely difficult, caught between the Scylla of safety (ensuring that accidental detonation of the explosive could not create even a small nuclear yield) and the Charybdis of effectiveness (ensuring that the weapon reached its design yield). Effective designs often proved unsafe, and modifications made to achieve safety often led to fizzles. As a result, despite the large number of tests, only a fairly small number of application systems were actually under development. For example, at least 10 shots were conducted to verify the safety and effectiveness of a primary for the XW-54 warhead. No more than 7 design types account for at least 29 of the tests. This series included tests of what is probably the lightest nuclear system feasible - the XW-51 Davy Crockett warhead - weighing only 16 kg in its tested form. The world's first underground nuclear test had been fired in the previous NTS series (Plumbbob Ranier), this series introduced underground testing as a routine procedure. The intention was to reduce the fallout effects of the testing, which were raising great concern, but the "underground" testing procedures were still relatively primitive. Many of these shots were conducted in "unstemmed" holes, that is, holes not back-filled and sealed prior to testing. These shots were called "roman candles" since the incandescent gas from the fireball was ejected as a jet from the mouth of the shaft. Obviously fallout containment was much less than perfect, but most of the fission product was nonetheless deposited in the shaft instead of escaping, and the radiation that did escape was not lofted so that it could travel far downwind. Hardtack Phase II still released some 3,140 kilocuries of radioiodine into the atmosphere (about equal to the Trinity test), and only 5% as much as the previous test series (Plumbbob). This radiation also did not spread nearly as far, only about one-millionth as much radiation exposure occurred to civilians. One of the weapons-related events, a 460 meter balloon shot called Adams, was scheduled for detonation on 31 October. The device was lowered and disarmed after midnight, however, because it had been determined that extensive overpressure damage to the nearby town of Indian Springs would have resulted from the detonation. Santa Fe - 30/10/1958 Test Shots Video Name Yield Date |UTC| Type Warhead Location LONG/LAT - Otero 0.038 Kt 20:00 12/09/1958 Shaft @-150m XW-54 NTS Area 3q 37.05000 -116.03190 - Bernalillo 0.015 Kt 19:30 17/09/1958 Shaft @-150m - NTS Area 3h 37.04940 -116.03300 - Eddy 0.083 Kt 14:00 19/09/1958 Baloon @150m - NTS Area 7b 37.08670 -116.02360 - Luna 0.0015 Kt 19:00 21/09/1958 Shaft @-150m XW-54 NTS Area 3m 37.04920 -116.03360 - Mercury 0 Kt 22:00 23/09/1958 Shaft @-55m XW-47 NTS Area 12f 37.19310 -116.20060 - Valencia 0.002 Kt 20:00 26/09/1958 Shaft @-150m XW-42 NTS Area 3r 37.04970 -116.02970 - Mars 0.013 Kt 00:00 28/09/1958 Tunnel @-42m XW-48 NTS Area 12f 37.19310 -116.20060 - Mora 2 Kt 14:05 29/09/1958 Baloon @460m XW-54 NTS Area 7b 37.08670 -116.02360 - Hidalgo 0.077 Kt 14:10 05/10/1958 Baloon @110m - NTS Area 7b 37.08670 -116.02360 - Colfax 0.0055 Kt 16:15 05/10/1958 Shaft @-150m - NTS Area 3k 37.04890 -116.03420 - Tamalpais 0.072 Kt 22:00 08/10/1958 Tunnel @-124m XW-48 NTS Area 37.19530 -116.20030 - Quay 0.079 Kt 14:30 10/10/1958 Tower @30m XW-50 NTS Area 7c 37.09470 -116.02360 - Lea 1.4 Kt 13:20 16/10/1958 Baloon @460m XW-54 NTS Area 7b 37.08670 -116.02360 - Neptune 0.155 Kt 18:00 14/10/1958 Tunnel @-30m XW-47 NTS Area 12c 37.19390 -116.19970 - Hamilton 0.0012 Kt 16:00 15/10/1958 Tower @15m XW-51 NTS Area 5 36.80220 -115.93220 - Logan 5 Kt 06:00 16/10/1958 Tunnel @-283m - NTS Area 12e 37.18420 -116.20110 Dona Ana 0.037 Kt 14:20 16/10/1958 Baloon @150m - NTS Area 7b 37.08670 -116.02360 - Vesta 0.024 Kt 23:00 17/10/1958 Surface XW-47 NTS Area 9e 37.12250 -116.03470 - Rio Arriba 0.090 Kt 14:25 18/10/1958 Tower @20m Mk-7 NTS Area 3s 37.04110 -116.02580 - San Juan 0 Kt 14:30 20/10/1958 Shaft @-70m XW-42 NTS Area 3p 37.04470 -116.02970 - Socorro 6 Kt 13:30 22/10/1958 Baloon @460m XW-54 NTS Area 7b 37.08670 -116.02360 Wrangell 0.115 Kt 16:50 22/10/1958 Baloon @460m XW-47 NTS Area 5 36.79810 -115.92890 - Oberon 0 Kt 20:30 22/10/1958 Tower @8m XW-47 NTS Area 8a 37.20000 -116.10000 - Rushmore 0.188 Kt 23:40 22/10/1958 Baloon @150m XW-47 NTS Area 9a 37.13470 -116.04080 - Catron 0.021 Kt 15:00 24/10/1958 Tower @20m - NTS Area 3t 37.04310 -116.02690 - Juno 0.0017 Kt 16:01 24/10/1958 Surface - NTS Area 9f 37.12330 -116.03780 - Ceres 0.0007 Kt 04:00 26/10/1958 Tower @8m XW-48 NTS Area 8b 37.18140 -116.06860 - Sanford 4.9 Kt 10:20 26/10/1958 Baloon @460m XW-47 NTS Area 5 36.79810 -115.92890 - De Baca 2.2 Kt 16:00 26/04/1958 Baloon @460m - NTS Area 7b 37.08670 -116.02360 - Chavez 0.0006 Kt 14:30 27/10/1958 Tower @16m - NTS Area 3u 37.05000 -116.00000 - Evans 0.055 Kt 00:00 29/10/1958 Tunnel @256m XW-47 NTS Area 12b 37.19470 -116.20470 - Mazama 0 Kt 11:20 29/10/1958 Tower @15m - NTS Area 9 37.10000 -116.05000 Humbodt 0.0078 Kt 14:45 29/10/1958 Tower @10m XW-51 NTS Area 3v 37.04780 -116.02470 - Santa Fe 1.3 Kt 03:00 30/10/1958 Baloon @460m - NTS Area 7b 37.08670 -116.02360 - Ganymede 0 Kt 11:00 30/10/1958 Surface W-45 NTS Area 9g 37.10000 -116.05000 - Blanca 22 Kt 15:00 30/10/1958 Tunnel @-254m W-47 NTS Area 12e 37.18580 -116.20190 - Titania 0.0002 Kt 20:34 30/10/1958 Tower @8m W-47 NTS Area 8c 37.17720 -116.06920