Greenhouse Item was an American nuclear test conducted on May 25, 1951, as part of Operation Greenhouse at the Pacific Proving Ground, specifically on the island of Engebi in the Eniwetok Atoll in the Central Pacific Ocean.
 This test explosion was the first test of a boosted fission weapon.
 In this test deuterium-tritium (D-T) gas was injected into the enriched uranium core of a nuclear fission bomb.
 The extreme heat of the fissioning bomb produced thermonuclear fusion reactions within the D-T gas, but not enough of them to be considered a full nuclear fusion bomb.
 This fusion reaction released a large number of free neutrons, which greatly increased the efficiency of the nuclear fission reaction.
 The explosive yield of this bomb was 45.5 kilotons, about twice the yield of the unboosted bomb.
Yucca Flat is a closed desert drainage basin, one of four major nuclear test regions within the Nevada Test Site (NTS), and is divided into nine test sections: Areas 1 through 4 and 6 through 10.
 Yucca Flat is located at the eastern edge of NTS, about 10 mi north of Frenchman Flat, and 65 mi from Las Vegas, Nevada.
 Yucca Flat was the site for 739 nuclear tests – nearly four of every five tests carried out at the NTS.
Frenchman Flat is a hydrographic basin in the Nevada National Security Site south of Yucca Flat and north of Mercury, Nevada.
 The flat was used as an and has a 15 km2 dry lake bed (Frenchman Lake) that was used as a 1950s airstrip before it was chosen after the start of the Korean War for the Nevada Proving Grounds.
 Nellis Air Force Base land 12 x was transferred to the Atomic Energy Commission on which Site Mercury was constructed on the flat for supporting .
 The 1951 Operation Ranger "Able" test (ground zero at UTM Coordinates 923758 on the flat) was the first continental US nuclear detonation after the 1945 Trinity test, and Frenchman Flat also had the only detonation of an American artillery-fired nuclear projectile in the 1953 Upshot-Knothole Grable test using the M65 Atomic Cannon.
Vihtori Vesterinen (27 January 1885, Kivijärvi - 28 June 1958) was a Finnish farmer and politician.
 He served as Deputy Minister of Agriculture from 31 March 1925 to 13 December 1926 and again from 17 December 1927 to 16 October 1928, Deputy Minister of Transport and Public Works from 7 October 1936 to 13 December 1937, Minister of Agriculture from 9 November 1945 to 29 July 1948, Deputy Minister of Social Affairs from 17 March 1950 to 17 January 1951, Deputy Minister of Transport and Public Works from 31 March 1950 to 17 January 1951 and Minister of Social Affairs from 17 January to 20 September 1951.
 He was a member of the Parliament of Finland from 1919 to 1951, representing the Agrarian League.
 He was the father of Paavo Vesterinen.
Operation Buster–Jangle was a series of seven (six atmospheric, one cratering) nuclear weapons tests conducted by the United States in late 1951 at the Nevada Test Site.
 "Buster-Jangle" was the first joint test program between the DOD (Operation "Buster") and Los Alamos National Laboratories (Operation "Jangle").
 As part of Operation "Buster", 6,500 troops were involved in the Operation Desert Rock I, II, and III exercises in conjunction with the tests.
 The last two tests, Operation "Jangle", evaluated the cratering effects of low-yield nuclear devices.
 This series preceded "Operation Tumbler-Snapper" and followed "Operation Greenhouse".
The Halfpint Range is a low arcuate mountain range in eastern Nye County and extending into southwest Lincoln County, Nevada.
 The western portion of the range lies within the Nevada Test Site.
 Yucca Flat and Plutonium Valley lie to west and Frenchman Flat to the south.
 The Buried Hills, the Papoose Range and Papoose Lake lie to the east.
 French Peak (5280 ft ) is at the south end and Banded Mountain (5336 ft ) lies at the north end of the range.
The Nevada National Security Site (N2S2),(though the abbreviation NNSS is still used), previously the Nevada Test Site (NTS), is a United States Department of Energy reservation located in southeastern Nye County, Nevada, about 65 miles (105 km) northwest of the city of Las Vegas.
 Formerly known as the Nevada Proving Grounds, the site was established on 11 January 1951 for the testing of nuclear devices, covering approximately 1,360 square miles (3,500 km) of desert and mountainous terrain.
 Nuclear weapons testing at the Nevada Test Site began with a 1-kiloton-of-TNT (4.2 TJ) bomb dropped on Frenchman Flat on 27 January 1951.
 Many of the iconic images of the nuclear era come from the NTS.
 NNSS is operated by National Security Technologies, LLC, a joint venture of Northrop Grumman, AECOM, CH2M Hill, and Babcock & Wilcox.
Upshot–Knothole Harry (UK#9) was a nuclear weapons test conducted by the United States as part of Operation Upshot–Knothole.
 It took place at the recorded time of 04:05 (05:05 hrs ) hours, on the May the 19th, 1953 in Yucca Flat, in the Nevada Test Site.
 The sponsor of the test was the National Laboratory of the United States of America located at Los Alamos.
596, originally named by the US intelligence agencies Chic-1, is the codename of the People's Republic of China's first nuclear weapons test, detonated on October 16, 1964, at the Lop Nur test site.
 It was a uranium-235 implosion fission device made from weapons-grade uranium (U-235) enriched in a gaseous diffusion plant in Lanzhou.
 The bomb had a yield of 22 kilotons, comparable to the Soviet Union's first nuclear bomb RDS-1 in 1949 and the American Fat Man bomb dropped on Nagasaki, Japan in 1945.
 With the test, China became the fifth nuclear power.
 This was the first of 45 total nuclear tests China has conducted to date, all of which occurred at the Lop Nur test site.
Operation Teapot was a series of fourteen nuclear test explosions conducted at the Nevada Test Site in the first half of 1955.
 It was preceded by "Operation Castle", and followed by "Operation Wigwam".
 "Wigwam" was, administratively, a part of "Teapot", but it is usually treated as a class of its own.
 The aims of the operation were to establish military tactics for ground forces on a nuclear battlefield and to improve the nuclear weapons used for strategic delivery.

Question: Which operation was conducted at a test site which began with a 1-kiloton-of-TNT (4.2 TJ) bomb dropped on Frenchman Flat on 27 January 1951?
Answer: Operation Teapot