This calculator surfaced in Greece but is probably of US origin. No author information is shown but its reference number is 6LS-2820. Its purpose is to calculate the amount of a chemical agent required to saturate a target using a number of different delivery systems [e.g. 4.2″ mortar, howitser, rocket or 100 gallon airborne spray tank].
The back of the calculator refers to agent GB. That is the nerve gas Sarin.
The directions also refer to agent HD. This is mustard gas. Agent VX is the VX nerve gas. Under the UK’s Rainbow Code system VX had the code name “Purple Possum”.
The disk refers to the US Honest John and Sergeant missiles as possible delivery vehicles. Honest John was first deployed in 1953 [and remained in the NATO arsenal until 1985] but the M139 chemical weapon warhead was not available for the Honest John until the 1960s.
M139 warhead containing Sarin bomblets
The Sargeant missile was deployed in Europe from 1963. A chemical weapon warhead option was considered but the development project was cancelled in 1970.
The calculator consists of three disks. The largest is made of card and is just under 5″ [125mm] in diameter. It is fairly crudely made compared to the very high quality Cold War calculators later produced by Perrygraf.
Please leave a comment if you have any more information on this calculator.
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.
The 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.
This 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.