Chevaline Penetration Aid Carrier (warhead platform) on display at RAF Kemble.

The Chevaline project was a secret project to improve the penetrability of the British Polaris missile system. The exact length and cost of the project was unknown for many years, but recently published research shows that it was first proposed in Nov 1966 by Defence Minister Denis Healey in a letter to the Prime Minister Harold Wilson, and before Polaris became operational in 1968 during the first Wilson government. The beginnings of the project can be traced to 1958 studies at the RAE (Royal Aircraft Establishment) to harden Blue Streak warheads because of concerns about future ABM capabilities. After Blue Streak cancellation these studies transferred to the Skybolt warheads that the RAE at Farnbrough also believed vulnerable. These studies transferred yet again to Polaris after Skybolt cancellation, and the RAE produced a study (HR.169) in 1964 that can be said to be the first appearance of what became the basis of the later Chevaline project. Image File history File links Chevaline2. ... Image File history File links Chevaline2. ... RAF Kemble was a Royal Air Force airfield that was linked for many years with the Red Arrows, the RAF Aerobatic display team which operated Hawk trainers from there. ... The Polaris Missile was a submarine-launched ballistic missile (SLBM) carrying a nuclear warhead developed during the Cold War for the United States Navy. ... Denis Winston Healey, Baron Healey, PC (born 30 August 1917), is a British Labour politician, regarded by some (especially in the Labour Party) as the best Prime Minister we never had. He was born in Keighley, Yorkshire. ... Sir Robert Walpole, the first Prime Minister of the United Kingdom. ... James Harold Wilson, Baron Wilson of Rievaulx, KG, OBE, FRS, PC (11 March 1916 – 24 May 1995) was one of the most prominent British politicians of the 20th Century. ... 1968 (MCMLXVIII) was a leap year starting on Monday (the link is to a full 1968 calendar). ... This article needs cleanup. ... The Blue Streak missile was a British ballistic missile development programme of the mid to late-1950s, the initial design being based on licensed U.S. technology. ... An anti-ballistic missile (ABM) is a missile designed to counter ballistic missiles. ... The Douglas GAM-87A Skybolt was an air-launched ballistic missile (ALBM) developed during the late 1950s. ...

The first costings identified specifically for Chevaline appeared in 1967 when approved by a Nuclear Policy Committee. As Super Antelope the early Chevaline programme was continued by the Heath Conservative government in 1973, and the final decision to commit to the production phase was taken by the Labour government in 1975. Test launches were conducted by 1977 [3], but the project was unknown to the general public until a government announcement in 1979 after a General Election in which the Labour Party administration lost power. The incoming administration of Margaret Thatcher felt obliged to disclose the project's existence because the project costs were now so large that parliamentary approval had to be sought for the project to be financed. Sir Edward Richard George Heath, KG, MBE (9 July 1916 – 17 July 2005), soldier and politician, was Prime Minister of the United Kingdom from 1970 to 1974 and leader of the Conservative Party from 1965 to 1975. ... The Conservative Party is the second largest political party in the United Kingdom in terms of sitting MPs, and the largest by of public membership. ... The Labour Party has, since the early twentieth century, been the principal left wing political party in the United Kingdom (see British politics). ... This page refers to the year 1979. ... Margaret Hilda Thatcher, Baroness Thatcher, LG, OM, PC, FRS (born 13 October 1925) was Prime Minister of the United Kingdom from 1979 to 1990. ...

Military and political requirements

The impetus to upgrade the system came about long before the Soviet deployment around Moscow of the Galosh ABM system. The Soviets were confirmed as working on an ABM system by 1961 when they made their first successful exo-atmospheric interception of an ICBM. An American response was to develop Antelope, a system designed to 'swamp' the ABM defence with decoys, penetration aids or 'penaids' but then the U.S. shelved Antelope because they concluded that with their very large stockpile of warheads, especially with the development of MIRVs, they could 'swamp' the ABM defences without penaids. The MIRVed U.S. Peacekeeper missile, with the re-entry vehicles highlighted in red. ...

The British did not possess a large stockpile of warheads, nor had they developed MIRV technology, and concluded that they had not the resources to do so for some time. However, they had a distinct national requirement for Polaris to be capable of the guaranteed destruction of Moscow. That was a capability that was not an essential requirement of the U.S.Navy Polaris missile, because the U.S. had large numbers of other systems also, that together as a team could obliterate the Soviet Union, swamping any defences. But British military planners required the small British Polaris force to be capable of being used alone without support from their allies; and as the only member of the team. To destroy the Soviet machinery of government centralised on Moscow, the British force used alone would need to be qualitatively improved, because by the early 1960s simple calculations showed that the probability of the small British Polaris force penetrating the Moscow defences and destroying the highly centralised machinery of Soviet government not likely, and with realistic system failures included, unlikely, even with more than one submarine on station. The outrageously crowded Woodstock festival epitomized the popular antiwar movement of the 60s. ...

The origins of that requirement grew from the conclusion of several British governments that in the event of a Soviet nuclear attack on the UK alone, as had been threatened on at least one occasion by Khruschev during the Suez crisis, and even with the UK a glowing heap of ashes, it was unrealistic to expect that the U.S. would retaliate against the Soviet Union and risk the destruction of most major American cities. That conclusion by sucessive British governments was the basis of their justification given to the British people for an independent nuclear retaliatory capability, although many people dissented at the time, as they still do. That conclusion also provided the impetus to improve penetrability of the British nuclear deterrent. Several options were considered over a protracted period of time, but the final choice fell on the Chevaline project, although there were dissenters, including the Navy who preferred to upgrade to Poseidon and maintain commonality with the U.S. Navy. State motto (Russian): Пролетарии всех стран, соединяйтесь! (Transliterated: Proletarii vsekh stran, soedinyaytes!) (Translated: Workers of the world, unite!) Capital Moscow Official language None; Russian (de facto) Government Federation of Soviet republics Area  - Total  - % water 1st before collapse 22,402,200 km² Approx. ... (Russian: , Nikita Sergeevič Hruščëv; surname commonly romanized as Khrushchev, IPA: ; April 17, 1894 – September 11, 1971) was the leader of the Soviet Union after the death of Joseph Stalin. ... Combatants United Kingdom, Israel, France Egypt Commanders Moshe Dayan (CoS of the IDF) General Sir Charles Keightley (C-in-C), Vice-Admiral Pierre Barjot (Deputy) Gamal Abdel Nasser Strength 45,000 British, 34,000 French, 175,000 Israeli 300,000 Egyptians Casualties 189 Israelis KIA, unknown number WIA, 16 British... Poseidon missile The Poseidon missile was the second US Navy ballistic missile system, powered by a two-stage solid fuel rocket. ...

Domestic political considerations at this time in the U.K. were secondary because of the thick veil of secrecy that surrounded the nuclear establishment, and as his predecessor Prime Minister Attlee had done with the early nuclear bomb programme, Prime Minister Wilson was careful to restrict knowledge of the project to a small inner group of his Cabinet, and especially away from the eyes and ears of its troublesome left-wing and anti-nuclear members. Even so, the project was bedevilled in its early years by an election manifesto pledge by Prime Minister Wilson that the U.K. would not produce another generation of nuclear weapons. Although a prime reason why Chevaline was deemed necessary was that the warhead fission element, the thermonuclear primary, was believed vulnerable to the Galosh system and would have to be replaced in toto, further hardening being deemed ineffective. How Wilson's pledge was circumvented is for another place. Clement Richard Attlee, 1st Earl Attlee, KG, OM, CH, FRS (January 3, 1883 - October 8, 1967) was Prime Minister of the United Kingdom from 1945 to 1951. ... An induced nuclear fission event. ... At the end of the 20th century, Thermonuclear has came to imply anything which has to do with fusion nuclear reactions which are triggered by particles of thermal energy. ...

Technical solutions.

After the U.S. discarded the Antelope decoy system they passed it to the British who adapted it as Super-Antelope, then KH.793, later re-labelled as Chevaline during the Edward Heath administration. In French, Chevaline translates as a dealer in horse flesh for human consumption; a common practice in France, but possibly an ill-advised label for a nuclear missile system, and a choice that generated much hilarity in the U.K. at the poor language skills of the Heath government. Binomial name Equus caballus Linnaeus, 1758 The horse (Equus caballus or Equus ferus caballus) is a large odd-toed ungulate mammal, one of ten modern species of the genus Equus. ...

The response to the threat of interception by Galosh was to deploy an upgraded or Improved Front End (IFE) to Polaris A3T using the Antelope/Super Antelope/Chevaline technology. Other solutions such as upgrading to the Poseidon system, increasing submarine availability or launcher reliability were either not practical, or thought too expensive. Upgrading to the Poseidon missile (Option M) was offered by the United States and was favoured by the Navy and the Combined Chiefs of Staff. With hindsight that is now seen to be a less costly option than Chevaline. A further consideration was that the submarine hulls had a further fifteen years expected life, and re-arming the boats with a suitable system effectively limited choice to Chevaline or Poseidon. The Poseidon missile was the second US Navy ballistic missile system, powered by a two-stage solid fuel rocket. ...

The Chevaline solution was to decrease the number of warheads carried by the Polaris system from three to two, using the space and weight to carry numerous decoys, and increase the likelihood of warhead survival by substituting a new super-hardened thermonuclear primary for the warhead contained in a new super-hardened RV. This was to be core of the Chevaline project, the tactic being to saturate the Moscow defences with multiple apparent threats, only two of these being real warheads. The simpler Option M Poseidon solution carried no decoys; it would merely use multiple warheads and high-speed RVs mounted on a de-MIRVed Poseidon missile to 'drench' the Galosh defences. This was offered by the U.S. as the best long-term solution to defeat the threat of terminal-defence ABMs that the Soviet Union seemed likely to develop whilst still in compliance with the ABM Treaty. With its blunt-nosed RV design and low terminal speed after re-entry, Chevaline was vulnerable to terminal-defence ABMs if they were ever deployed. For other uses, see Moscow (disambiguation). ...

The Chevaline project involved building a penetration aid carrier (PAC) which mounted one of the two hardened RVs, and a series of deployable penetration aids. The second RV was mounted directly on the end of the second-stage booster as the earlier Polaris warheads had been mounted, and suggests that this RV was targetted by the missile trajectory rather than the manouverable PAC. The PAC dispensed one RV but the principal purpose of its manouvering capability was to dispense the 27 decoys into a 'threat tube' surrounding the RVs, which also had a 'disguise' to match their radar appearance to the decoys. The system was not a MIRVing system because the target of both warheads was one location, about which the two warheads were spread, as in the earlier MRV system of Polaris A3T. Wikipedia does not yet have an article with this exact name. ...

The project was carried out in extreme secrecy by a team consisting of the Atomic Weapons Establishment (AWE) at Aldermaston, the Royal Aircraft Establishment (RAE) at Farnborough, and Hunting Engineering at Ampthill, Sperry Gyroscope at Bracknell, Lockheed Aerospace in the United States, and others too numerous to mention, both in the U.S. and the U.K. The system was tested at the US Eastern Test Range, Cape Canaveral, and the warheads were tested with two full scale underground nuclear tests (Fallon UGT and Banon UGT) at the Nevada Test Site. There were also numerous weapon effects tests to prove the RV/warhead resistance to the radiation-effects of the Galosh warhead; and there were numerous missile tests at the Woomera Missile Range, Australia, to develop various aspects of the RVs, the PAC and decoys. Recent declassifications of official files show that more than half the total project costs were spent in the United States, with industry and government agencies. AWE plc logo The Atomic Weapons Establishment, Aldermaston (formerly the Atomic Weapons Research Establishment, Aldermaston) is situated in the UK, just 7 miles north of Basingstoke and approximately 14 miles south-west of Reading, Berkshire, near a village called Aldermaston, bordering with Tadley. ... View of Aldermaston village circa 1959 Aldermaston is a village in the English county of Berkshire, two miles north of Tadley. ... This article needs cleanup. ... Farnborough is a town in the Rushmoor borough of Hampshire in South East England. ... INSYS is a British defense contractor, located in Ampthill. ... Location within the British Isles Ampthill is a small town in Bedfordshire, England, between Bedford and Luton, with a population of about 6,000. ... Sperry Corporation was a major American equipment and electronics company whose existence spanned more than seven decades of the twentieth century. ... Map sources for Bracknell at grid reference SU870693 Charles Square, Bracknell Bracknell is a town in the Bracknell Forest borough of Berkshire, England. ... The Lockheed SR-71 was remarkably advanced for its time and remains unsurpassed in many areas of performance. ... Cape Canaveral from space, August 1991 Cape Canaveral (Cabo Cañaveral in Spanish) is a strip of land in Brevard County, Florida, United States, near the center of that states Atlantic coast. ... November 1951 nuclear test at Nevada Test Site. ...

Range of the "Improved" Chevaline system was 22% less than the "Unimproved" Polaris A3T reduced from 2'500 nautical miles to 1'950 nm, and this was the source of continuing pressure on the development team from the Naval Staff, who had set the minimum requirement at 2'000 nm, and who were deeply concerned at intelligence reports of improving Soviet ASW (anti-submarine-warfare). Reduced missile range due to the increased weight of Chevaline and poor weight control by the developers had the effect of reducing the sea-room in which the British submarines could hide. Efforts were made to reduce warhead weight by substituting a new, smaller, high-yielding thermonuclear primary tested at Fondutta UGT and Quargel UGT, and although these tests were deemed successful, the delays involved in preparing them for Chevaline were thought to risk further unacceptable delays to the in-service date planned, and they were not used. This thermonuclear primary was by then being referred to in official documents as a "trigger device" and some suspect that this new description was a sleight-of-hand to circumvent the pledge given by Prime Minister Wilson of "no new generation of nuclear weapons". The thermonuclear (or fusion) secondary for Chevaline and known to AWRE by the codename Reggie, is known from these declassified documents to be recycled from the "Unimproved" Polaris A3T warhead. It seems that AWRE were in the recycling business before it became fashionable in the wider world. Anti-submarine warfare is a term referring to warfare directed against submarines. ...

The integrated upgraded Polaris system was called A3TK. This system was in service from 1982 to 1996, when it was replaced by Trident. The Trident missile, named after the trident, is an intercontinental ballistic missile (ICBM) which is armed with nuclear warheads and is launched from submarines (SSBNs), making it a SLBM. The Trident was built in two variants: the I (C4) UGM-96A and II (D5) UGM-133A. The C4 and D5...

Further political developments.

As stated above, the Chevaline project was kept secret by a succession of UK governments, both Labour and Conservative. This included the governments of Harold Wilson, Edward Heath, Harold Wilson's second term and James Callaghan. The project was finally revealed by Margaret Thatcher's then defence minister Francis Pym. The reasons for revelation were both political and practical. The cost over-runs of the project were now so enormous (approx £1billion in 1979) that the secret inner cabinet spending approvals could not continue. The Thatcher government did not terminate the project. The key decision to proceed had been taken in 1975 four years previously, and cancellation would be unlikely to save money, while leaving a huge void in Britain's defence capability. Britain would effectively cease to have a strategic nuclear deterrent force, leaving France as the only European nuclear power, and that was a powerful factor in the government's motives for continuing; and the point where an essential decision was required about a successor to Chevaline had also arrived. Shortly afterwards the Thatcher government decided that the successor system should be the Trident system and ordered the C4 variant. James Harold Wilson, Baron Wilson of Rievaulx, KG, OBE, FRS, PC (11 March 1916 – 24 May 1995) was one of the most prominent British politicians of the 20th Century. ... Sir Edward Richard George Heath, KG, MBE (9 July 1916 – 17 July 2005), soldier and politician, was Prime Minister of the United Kingdom from 1970 to 1974 and leader of the Conservative Party from 1965 to 1975. ... James Harold Wilson, Baron Wilson of Rievaulx, KG, OBE, FRS, PC (11 March 1916 – 24 May 1995) was one of the most prominent British politicians of the 20th Century. ... The Right Honourable Leonard James Callaghan, Baron Callaghan of Cardiff, KG, PC (March 27, 1912 – March 26, 2005), was Labour Prime Minister of the United Kingdom from 1976 to 1979. ... Margaret Hilda Thatcher, Baroness Thatcher, LG, OM, PC, FRS (born 13 October 1925) was Prime Minister of the United Kingdom from 1979 to 1990. ... Francis Leslie Pym, Baron Pym, PC, (born February 13, 1922) is a UK politician and former member of the Cabinet. ... The Trident missile, named after the trident, is an intercontinental ballistic missile (ICBM) which is armed with nuclear warheads and is launched from submarines (SSBNs), making it a SLBM. The Trident was built in two variants: the I (C4) UGM-96A and II (D5) UGM-133A. The C4 and D5...

The Naval Staff angst that had been a feature of the Chevaline project surfaced here too. For several reasons the Navy had not wanted Chevaline and had actively lobbied against it. Their preference for Poseidon was in large part based on commonality of equipment. Polaris was being phased out of use by the U.S.Navy and supplies of spares and repair facilities were becoming unavailable. To keep the Polaris missile in use in the U.K. meant that some production lines had to be re-opened at great cost to supply a very small force. A missile common to both navies was desirable, and the Naval Staff strongly argued against Chevaline. Although the papers will not be declassified for some time yet, it seems likely that the Naval Staff made the same case with Trident with some success when their influence was at its height after the Falklands War. The Thatcher government then changed its Trident order to the larger D5 variant, and agreed a deal whereby the U.S. and British combined missile stock is serviced at a single location at the U.S. Navy facility at King's Bay, Georgia, and from there missiles are issued to both U.S. and British submarines. Only the warheads (added later to British missiles) are different. Combatants United Kingdom Argentina Casualties 255 killed 777 wounded 1 taken prisoner 649 killed 1,068 wounded 11,313 taken prisoner The Falklands War (Spanish: Guerra de las Malvinas) was an effective state of war in 1982 between Argentina and the United Kingdom over the Falkland Islands (also known in...

Finally, recently published recollections from senior members of the development team are explicit in stating that Chevaline was not the best, or with hindsight, the cheapest choice the British could have made from the many options available. But the choices were never simple but overlaid with what was politically possible, what was in the best interests of U.K. industry and its scientific base. In the end, the alternatives were "between Chevaline or nothing at all; a decision which could easily have meant withdrawal of the U.K. from the military political nuclear scene" and that option was unthinkable to the military staffs and government alike.

External references

• http://www.skomer.u-net.com/projects/chevaline.htm (now dated obsolete inaccurate source).
• http://www.astronautix.com/lvs/polrisa3.htm (now dated obsolete inaccurate source).
• http://www.fas.org/nuke/guide/uk/slbm/chevaline.html(now dated obsolete inaccurate source).
• http://www.mcis.soton.ac.uk/Site_Files/pdf/nuclear_history/glossary.pdf
• Dr Richard Moore. Prospero/Journal of the BROHP, 2004.
• Dr Frank Panton. The Unveiling of Chevaline. Prospero/Journal of the BROHP, 2004.
• Dr Frank Panton. Polaris Improvements and the Chevaline Programme. Prospero/Journal of the BROHP, 2004.
• Dr Peter Jones, Director, AWE (Ret). The Chevaline Technical Programme. Prospero/Journal of the BROHP, 2005.
• Numerous authors and papers published as Proceedings of a Royal Aeronautical Society Symposium held Oct 2004. Published as ISBN 1-185768-109-6. An abridged version is available as an email download from User:Brian.Burnell. Contact via Talk page.
• The National Archives, London. Numerous declassified Ministry of Defence, Ministry of Aviation, AWRE and Prime Minister's files. All public domain.
• Chuck Hansen. Swords of Armageddon. 1995.