Operation Greenhouse - Nuclear Test Series 1951

Much of the post war period that was the Cold War, was spent attempting to build a bigger, more powerful, and more accessible nuclear/thermonuclear weapon to deter the enemy from attacking. The Cold War saw the establishment of Churchill's famous "Iron Curtain" dividing the world between the Eastern Bloc and the Western Bloc.

In 1951 the United States conducted its 5th Nuclear test series, code named Operation Greenhouse. As with any scientific test, the United States began experimenting with the concept of thermonuclear weapons, more commonly known as Hydrogen Bombs. This series of tests took place at the newly established Pacific Proving Ground. The test series would encompass four detonations, each mounted on steel towers to simulate areal detonations.

The four tests of Greenhouse represented a new aggressive design of nuclear weapons, looking to take the ultimate weapon one step further. Traditional nuclear weapons were very large in size, weight and required a high amount of fissile material. The ideas behind Greenhouse were to reduce each of the above traditional requirements to build more powerful weapons with less material, making them more operational.

A year and a half before Operation Greenhouse, on August 29 1949, the Soviet Union detonated RDS-1, nicknamed "Joe-1." The test yielded 22 Kilotons, and surprised the world. The United States only detected radioactive fission products days after the blast, and traced them back to the USSR. On September 23rd 1949, President Harry Truman announced to the world that the Soviet Union had successfully detonated an atomic bomb. This statement is considered by many to be the official beginning of the Cold War, as both the United States and the Soviet Union began working on the first Hydrogen Bomb.

The first two tests of Greenhouse, were of traditional nuclear weapons with minor adjustments to the firing mechanism. "Dog" tested on April 8th 1951 yielded 81 kilotons, and "Easy" tested on April 21st 1951 yielded 47 kilotons. It was the last two tests of this series that took major steps forward to designing a Hydrogen Bomb.

"George" was tested on the 9th of May 1951 and was the first recorded thermonuclear experiment conducted by the United States.  "George" was actually considered a thermonuclear burn, due to the addition of a small amount of heavy isotopes of liquid hydrogen (deuterium and tritium) that were injected into the core of the bomb. "George" acted more liked a boosted nuclear bomb than a Hydrogen bomb. The findings from "George" validated the theories that brought about the ideas of a thermonuclear weapon, and would be used when designing "Ivy Mike." "George" yielded 225 kilotons.

"George" Test shot mushroom cloud. nuclearweaponarchive.org

The final test of Operation Greenhouse was "Item." Like "George," "Item" was a test of a boosted fission weapon. "Item" was injected with deuterium-tritium gas into the uranium core.The heat of the gas produced a thermonuclear fusion reaction, but not enough to be fully considered a fusion bomb. The planning behind "George" and "Item" was from the great mind of Dr. Edward Teller in 1947. Teller has designed the idea of a booster to create a more powerful reaction, causing a larger detonation. While much smaller than "George", "Item" yielded 45.5 kilotons, but proved effective in pumping the booster gas into the weapon before detonation. The test was primarily a test of the nuclear principles involved and to gain valuable research data. It was never considered a design for weaponizing a device.

The nuclear discoveries that Operation Greenhouse provided helped the United States design and successfully test "Ivy Mike" in November 1952.  Thermonuclear Weapons would change the face of the Cold War, as would bigger and larger nuclear bombs.

Remembering History - Operation Greenhouse

Starfish Prime - Nuclear Test July 9, 1962

In July of 1962, visitors to the Island of Honolulu, Hawaii where treated to the visual show of a lifetime. It was in July of 1962, when the U.S. decided to perform a exoatmospheric (in space) Nuclear Test, in response to the Soviet Unions decision to end a three year ban on nuclear testing.

Code named, Starfish Prime, it was to be one of five planned high altitude nuclear tests as part of Operation Fishbowl, within the larger Operation Dominic. These Operations where designed to test the viability of nuclear weapons in space. 

In 1958 the U.S. had conducted other high altitude nuclear testings, but decided that "Previous high-altitude nuclear tests: Yucca, Teak, and Orange, as well as the three Argus tests were poorly instrumented and hastily executed."  (Defence Atomic Support Agency. Project Officer's Interim Report: STARFISH Prime. Report ADA955694. August 1962 )

Before the successful Starfish Prime test, the U.S. had some minor complications with Operation Fishbowl. The first planned high altitude test, Bluegill, was on a perfect trajectory when it was lost by the radar tracking facility, and was ordered destroyed on June 2, 1962. On June 19, the second test proceeded, codenamed Starfish. The Thor rocket launched went according to plan, when the missile stopped at between 30,000 and 35,000 feet and began to break apart. The missile was ordered destroyed.

On July 9, the W49 thermonuclear warhead was loaded on to a third Thor missile, and launched and exploded at 9am (CUT) Starfish Prime was launched. It was 11pm local time (on July 8th) in Honolulu, where hotel patrons raced to the rooftops of their hotels, or the beaches. Wherever they could get a sight of the night sky over Johnston Island, despite the fact that they were a mere 1,400 km away.

At 400 kilometres above the island, the explosion caused an aurora effect on the night sky, and created an electromagnetic pulse (EMP), a pulse much larger than anticipated, and caused the measurement equipment to fail, as well as thousands of electronics on the surrounding islands, including TVs, radios, home alarms, and street lights.  The 1.4 Megaton detonation caused the immediate failure of several low orbit satellites, and within the coming days, the radiation Field would cause the malfunction of 1/3 of low orbit satellites.

 The aurora was visible for approximately ten minutes, before beginning to fade, and was silent. There was no fireball or mushroom synonymous with nuclear explosions created by the Starfish Prime test, as there was no oxygen for the weapon to ignite.

The lasting effects of the test, created a series of man made radiation belts circling the earth, causing further problems for the low orbit satellites. The radiation affected their solar panels, and electronic components.  It was estimated by Journal of Geophysical Research that these radiation belts remained for at least 5 years.

It was not all for nothing, the Thor rocket also carried a cadmium (109) tracer that helped scientists predict the seasonal mixes of polar and tropical air, as well as led to better understanding of the EMP effect of nuclear weapons.

Operation Fishbowl would see another 2 failed attempts at atmospheric tests, before finishing on a high note, with 4 successful tests.

Remembering History - Starfish Prime Nuclear Test