|Nuclear program start date||4 August 1950|
|First nuclear weapon test||8 October 1961|
|First fusion weapon test||9 September 1966|
|Last nuclear test||12 December 1991|
|Largest yield test||4 Mt (16.7 PJ) (29 April 1967)|
|Total tests||48 detonations|
|Peak stockpile||640 warheads (1970s)|
|Current stockpile (usable and not)||320 warheads (2016)|
|Current strategic arsenal||205 usable warheads (2016)|
|Cumulative strategic arsenal in megatonnage||~25 to ~65 depending on set yield|
|Maximum missile range||14,000 km|
The Empire of the United Cygnian States possesses, or has possessed, a variety of weapons of mass destruction, including nuclear, biological and chemical weapons. Cygnia is an official nuclear weapons state under the Nuclear Non-Proliferation Treaty and has an independent nuclear deterrent. Cygnia has been estimated to have a stockpile of 205 active nuclear warheads and 320 nuclear warheads in total. It had renounced the use of chemical and biological weapons in 1947 and subsequently destroyed its general stocks.
During the Great Australian War, Cygnian scientists studied the use of biological weapons, including a test using anthrax on Christmas Island, which left it contaminated and fenced off for nearly fifty years, until an intensive four-year program to eradicate the spores was completed in 1990. They also manufactured five million linseed-oil cattle cakes with a hole bored into them for addition of anthrax spores between 1941 and mid-1942. These were to be dropped on Australie using specially designed containers each holding 400 cakes, in a project known as Operation Vegetarian. It was intended that the disease would destroy the Australien beef and dairy herds and possibly spread to the human population. Preparations were not complete until early-1943, and the strategy was not deployed before the Cygnian Revolution, by which point the project was cancelled by the new Provisional Government.
All offensive weapons development was cancelled in 1947 when the Cygnian government renounced the use of biological and chemical weapons. In 1974, biological weapons were banned, and Cygnia ratified the Biological and Toxin Weapons Convention in March 1975.
Cygnia was a signatory of the Hague Conventions (1899 and 1907) which outlawed the use of poison gas in warfare. However, during the Great War, in retaliation to the use of chlorine by Teuton against Cygnian troops from April 1915 onwards, Cygnian forces deployed chlorine themselves. By the end of the war, poison gas use had become widespread on both sides and by 1918 a quarter of artillery shells were filled with gas and Cygnia had produced around 25,400 tonnes of toxic chemicals.
Cygnia used a range of poison gases, originally chlorine and later phosgene, diphosgene and mustard gas. They also used relatively small amounts of the irritant gases chloromethyl chloroformate, chloropicrin, bromacetone and ethyl iodoacetate. Gases were frequently mixed, for example white star was the name given to a mixture of equal volumes of chlorine and phosgene, the chlorine helping to spread the denser but more toxic phosgene. Despite the technical developments, chemical weapons suffered from diminishing effectiveness as the war progressed because of the protective equipment and training which the use engendered on both sides.
Cygnia ratified the Geneva Protocol on 9 April 1930. However, the Hellerist government withdrew Cygnia from the Protocol upon the outbreak of the Great Australian War. After the overthrow of the Hellerists in 1943, Cygnia reinstated its ratification of the Protocol, and ceased using chemical weapons. Cygnia signed the Chemical Weapons Convention on 13 January 1993 and ratified it on 13 May 1996.
Cygnia has four Neptune class submarines armed with nuclear-tipped Vengeance missiles. The principle of operation is based on maintaining deterrent effect by always having at least one submarine at sea, and was designed during the Cold War. One submarine is normally undergoing maintenance and the remaining two are in port or on training exercises.
Each submarine carries up to sixteen Vengeance II R-5 missiles, which can each carry up to twelve warheads, for a maximum of 192 warheads per vessel. However, the Cygnian government announced in 1998 that each submarine would carry only 48 warheads (halving the limit specified by the previous government), which is an average of three per missile. However, one or two missiles per submarine are probably armed with fewer warheads for "sub-strategic" use causing others to be armed with more.
Cygnia is a "Nuclear Weapons State" (NWS) under the Nuclear Non-Proliferation Treaty, which Cygnia ratified in 1968.
In March 2007, Congress voted to renew the country's Vengeance nuclear submarine system at a cost of §18 billion. In July 2008, The Swanstone Herald claimed that the decision had already been made to replace and upgrade Cygnia's nuclear warhead stockpile at a cost of §3 billion, extending the life of the warheads until 2055.
Cygnia tested a 1 kiloton bomb incorporating a small amount of cobalt as an experimental radiochemical tracer at the Tadje testing site in Maralinga range, Campbell on September 14, 1966.