Category Archives: Cold War

Before and after a nuclear attack on the UK

A set of posters produced by the Home Office Civil Defence department in 1958. The posters showed the effects of a nuclear attack on British cities. The posters were printed by the Hydrographic Supplies Establishment and sold for one pound, seven shillings and six pence.

The posters are 29 inches by 23 inches.









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Nuclear war by accident

Eric Schlosser has a fascinating and frightening article [World War Three, by Mistake] in the New Yorker  which describes how close we came to accidental annihilation during the Cold War, and how close we are to it now.

When the US public see their military idiots prodding the bear by posturing around Europe and wingnuts like Senator John McCain describe Putin as “a thug, a bully, and a murderer” they might want to think about what will happen if things go wrong and they prod too much.

The photo below shows a Russian Voevoda R-36M2 missile being loaded into a silo somewhere in Russia. Each missile carries up to ten warheads and up to 40 penetration aids to overwhelm enemy defences. Russian missile technology is much superior to that of the US and their missiles have a greater throw weight than US missiles like the Minuteman.  That technical superiority is why the US has to buy rocket engines from Russia.

There are at least 46 R-36M2  complexes. Probably the US knows where most of  are and could destroy most of them in a first strike. I very much doubt if it knows where all of them are and could destroy them all. If even one or two of them got out of their silos the US would become a third world country with ten or twenty of its largest cities destroyed. Don’t worry though, US senators and military commanders would be safe underground when the warheads arrived. Nobody important would be harmed.


This post describes what would happen if a 800 kiloton warhead detonated over Manhattan.


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Cold War Calculator for Radiation Contaminated Food

A rare British Cold War calculator. Presumably intended for use  by civil defence after a nuclear attack.




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Nuclear Proving Grounds and stick charts

After WW2 the USA needed to develop and test its nuclear technology. It set up two proving grounds.

Nevada Proving Ground

The Nevada Proving Ground was only 65 miles from Las Vegas and gamblers could watch the mushroom clouds from the casinos and hotels. Most of the 928 tests were under ground but 100, including the notorious ‘Dirty Harry;’ test, were atmospheric. and winds  carried the fallout of these  to the west. The town of St. George was particularly badly affected and there were  increases in  leukaemia, lymphoma, thyroid cancer, breast cancer, melanoma, bone cancer, brain tumours, and gastrointestinal tract cancers. Over 200,00 cases of thyroid cancer were believed to have been caused [see this post].  Nuclear Test Participation certificates were issued to the people who took part in testing [see post]

Pacific Proving Ground

Only low yield weapons were tested in Nevada. Most of the big bangs took place in the Pacific Proving Ground [1946-62], on the Enewetok and Bikini Atolls in the Marshall Islands. A few of the later tests were conducted on Christmas Island and Johnston Atoll.


A total of 105 atmospheric and underwater tests were conducted in the Marshall Islands. This was only 14% of the total number of tests but accounted for 80% of the megatonage, The estimated total yield of the Marshall Islands tests was about 210 megatons, including the 15 Mt Castle Bravo shot on Bikini in 1954. The Castle Bravo bomb got out of control and produced over twice the expected yield, spreading radioactive contamination over several of the Marshall Islands atolls and a large area of the Pacific.


An atomic stick chart

The Marshall Islands are known for the stick charts charts their navigators created to help them sail between their 29 atolls and 5 islands. These are spread over a huge area of sea and navigation was a non trivial problem. I have made a stick chart to clarify the geography and identify the atolls that the USA used for military purposes. There is  more about stick charts in a separate post.


The Enewetok and Bikini [the swimsuit was named after the atoll] atolls were the ones used for testing. Kwajalien is still used by the USA as the the Ronald Reagan Ballistic Missile Defense Test Site. Majuro is the capital of the Marshall Islands. To give some idea of scale; it is 539 miles from Bikini to Ebon, the same distance as from London to Leipzig. The circular calculator in the bottom left is a Time Conversion Computer [see this post].

Testing began on Bikini  in 1946 with the Crossroads tests Two 21 kiloton atomic bombs were detonated. ‘Able’ was an atmospheric test [video] and ‘Baker” an underwater test [video]. The Baker bomb was exploded at a depth of 27 meters in the middle of a small fleet of ex WW2 vessels. The dangers of radioactivity were not fully understood then and sailors were sent to try a scrub ‘clean’ the highly contaminated vessels.

Testing then moved to Enewetok Atoll for the Sandstone, Greenhouse and Ivy series of tests. After that testing took place on both Enewetok and Bikini until  Operation Dominic in 1962 which involved 36 bombs being detonated above and near Johnston Atoll and Christmas Island.

Both Enewetok and Bikini remain heavily contaminated. Bikini is now a UNESCO World Heritage site. The natives of the Marshall Islands suffered form American operations in the Pacific Proving Ground, but not as badly as the natives of Utah and the mid west suffered from the operations in the Nevada Proving Ground.

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The DNA Multi-sigma Damage Prediction Rule MSIG – 1 Cold War slide rule

The MSIG – 1  Multi-sigma slide rule was produced by the US Defense Nuclear Agency to assist military planners in calculating the probability of damage resulting from a nuclear detonation.

DNA MSIG-1 Multi-Sigma Damage Prediction Rule 2

The rule is 8″ [205 mm] in diameter and  produced by Perrygraf. It was designed by the DNA and is dated April 1987. This rule is very collectable but the hardest to find of all the DNA slide rules. The one shown was never issued and is in mint condition.

DNA MSIG-1 Multi-Sigma Damage Prediction Rule 3

DNA MSIG-1 Multi-Sigma Damage Prediction Rule 4

The MSIG -1 was the last slide rule to be produced by the DNA. After that they only supplied software for use on desktop and hand held machines. A list of the slide rule and software can be found in this post.

The complete package as issued consisted of a binder, hard cover, documentation, slide rule and two floppy disks.

DNA MSIG-1 Multi-Sigma Damage Prediction Rule 1

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The Defense Nuclear Agency’s Cold War calculators

The Defense Nuclear Agency was an offspring of the Manhattan Project and is now part of the Defense Threat Reduction Agency. In its various guises it had many responsibilities connected with America’s nuclear weapons programmes.

In the 1980s and 1990s it produced a series of calculators to help the military plan its nuclear attacks on targets in the USSR and other countries. The US had a list of target Vulnerability Numbers [see this post].  Planners could use these numbers and the DNA calculators to decide whether  a bomber, a submarine launched missile or a ground launched missile be used against a target [they had different levels of accuracy] to achieve a specified level of damage and probability of success.

Vulnerability Numbers 1The first calculators were circular slide rules, designed by the DNA and produced by Perrygraf. These rules are now both very collectable and very rare. A list of these rules is below.

Defense Nuclear Agency Cold War slide rules and software 4This blog has posts on all these. The list is incomplete because the DNA produced a Damage Prediction Rule VN – 1 in 1982 [see this post].

As soon as a introduction of the IBM PC created a technical standard for personal computers the DNA began producing nuclear targeting software programs.  Some of the DNA’ss programs duplicated the functionality of the above slides rules. The Multi-sigma Damage Prediction Rule was produced as both a physical slide rule and as  software programs for hand held and desktop machines.  Programs for a long list of other targeting functions were added to the DNA catalogue.

Defense Nuclear Agency Cold War slide rules and software 2

Defense Nuclear Agency Cold War slide rules and software 3

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Defending Chicago [Part 1] – A New Threat

Nike missile batteries 02

During the 1950s the USA military started to worry that Russian bombers might fly over the Arctic and Canada and drop nuclear bombs on American cities.

The decision to drop atomic bombs on Japanese cities did little to shorten the war but it did create an existential threat to the USA.  Several things  followed from the American’s demonstration that  nuclear bombs worked, that they had some and were prepared to drop them on civilian targets.

1   Other countries would have to have such bombs or be prepared to obey America. Sure enough, in 1949 The Soviet Union detonated Joe -1, its first atomic bomb. Five years before the CIA expected the Soviet Union to have a A bomb.  The bomb was about Hiroshima size.

2   Bombs would get more powerful. In 1952 the USA tested a 10.4 megaton hydrogen bomb, but it was too heavy to be deliverable. In 1953 the Soviet Union tested a hydrogen bomb which had a much lower yield but was deliverable.  Soon both sides had multimegaton hydrogen bombs which were deliverable.

Until the US introduced the world to the nuclear age America had been effectively immune to aerial bombing. Now it wasn’t and the bombs were a lot more powerful. A successful attack could turn the USA into a third world country.


The US military realised that America was almost defenceless.  In a simulated Soviet attack [Operation Tailwind], 94 SAC bombers tested the air defence system of the continental USA by flying over Canada at night, and using electronic countermeasures to simulate a Soviet raid. Only 7 of the planes were spotted by radar and “shot down.

America had no reliable way of detecting approaching Soviet bombers. If incoming bombers were detected there was no good way of destroying them.

It might not even know  it had been attacked. If Los Angeles was destroyed or the SAC base at Homestead in Florida, how long would it take for Washington and SAC at Omaha to realised what had happened?  Probably too long. Even more worrying; what if the USA wrongly believed it was being attacked and started WW3?

In 1961, when tensions were very high during the Berlin Crisis, SAC headquarters in Omaha lost contact with the  Thule radar base in Greenland. A SAC officer called NORAD headquarters in Colorado Springs to find out what was wrong. The line was dead. Both Thule and NORAD were considered key bases that were likely to be hit very early in any Soviet attack. That they were both offline strongly suggested that an attack was in progress. A technical fault seemed unlikely since one base was east of Omaha and the other to the west.

It later emerged that a single AT & T switch in Black Forest, Colorado had failed and cut most of SAC and NORAD’s communications circuits. AT & T had not provided redundant switches, despite have told the US government that it had done so.

General LeMay of SAC thought that spending money on defence was a waste of time since some Russian bombers would always get through. He believed that all the money should be spent on offensive weapons. ‘ If the Soviets launched an attack with 200 bombers and American forces somehow managed to shoot down 90 percent of those planes, the United States would still be hit by at least 20 H-bombs, if not more.’  [Quoted in the excellent  Command and Control. by Eric Schlosser 2013]. Being a psychopath he did not realise that saving even a single American city was worthwhile.

LeMay’s arguments did not prevail and the USA began building its defences.

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