Operation HARDTACK II Nuclear Events, 1958 (Continued)
Event
Date
Type
Yield
(kilotons)
LOGAN
16 October
Tunnel
5
DONA ANA
16 October
Balloon
0.037
RIO ARRIBA
18 October
Tower
0.090
SOCORRO
22 October
Balloon
6
WRANGELL
22 October
Balloon
0.115
RUSHMORE
22 October
Balloon
0.188
SANFORD
26 October
Balloon
4.9
DE BACA
26 October
Balloon
2.2
EVANS
29 October
Tunnel
0.055
MAZAMA
29 October
Tower
NMY*
HUMBOLDT
29 October
Tower
0.0078
SANTA FE
30 October
Balloon
1.3
BLANCA
30 October
Tunnel
22
*No measurable yield
4.17.1
Background and Objectives of Operation HARDTACK II.
HARDTACK II was the last nuclear test series before the United States
adopted a nuclear test moratorium, which had originally been intended to last
1 year but continued until 1961.
The nuclear weapons tests were conducted to
evaluate the yield and efficiency of newly developed nuclear devices (21: 1,7).
Concern about nuclear weapon proliferation intensified throughout the
1950s, particularly after the BRAVO test of Operation CASTLE and the heavy
fallout resulting from this shot.
India proposed a cessation of tests.
At that time, Prime Minister Nehru of
The call for a test ban figured
repeatedly in disarmament discussions, most importantly, those of the
Disarmament Subcommittee of the U.N. Disarmament Commission,
18 March to 6 September 1957.
in session from
Continuing pressure on the nuclear powers to
reach an agreement on limiting testing resulted in the Conference on
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