Editing Astute-class submarine (section)

===Batch 2 ''Trafalgar'' class===
The ''Astute''-class programme began in February 1986 when the [[Ministry of Defence (United Kingdom)|Ministry of Defence]] (MOD) launched a number of studies intended to determine the capabilities and requirements for the replacement of its ''Swiftsure'' and ''Trafalgar''-class fleet submarines.<ref>{{cite hansard |jurisdiction=Parliament of the United Kingdom |title=Nuclear-Powered Submarines |url=https://hansard.parliament.uk/Commons/1991-07-04/debates/5912ce42-44b7-47e8-9ca9-de3bd8450495/Nuclear-PoweredSubmarines?highlight=ssn20#contribution-ffcb9a53-a6eb-4c6c-aae9-e93138230430 |house=House of Commons |date=4 July 1991 |column=214 |speaker=Mr. Kenneth Carlisle |position= }} {{Webarchive|url=https://web.archive.org/web/20210309054931/https://hansard.parliament.uk/Commons/1991-07-04/debates/5912ce42-44b7-47e8-9ca9-de3bd8450495/Nuclear-PoweredSubmarines?highlight=ssn20#contribution-ffcb9a53-a6eb-4c6c-aae9-e93138230430 |date=9 March 2021 }}</ref><ref name="RAND">{{cite book|title=Lessons from the United Kingdom's Astute Submarine Program|publisher=RAND National Defence Research Institute|location=United States|edition=Learning From Experience: Volume III|url=http://www.rand.org/content/dam/rand/pubs/monographs/2011/RAND_MG1128.3.pdf|access-date=27 July 2016|archive-date=21 October 2014|archive-url=https://web.archive.org/web/20141021094622/http://www.rand.org/content/dam/rand/pubs/monographs/2011/RAND_MG1128.3.pdf|url-status=live}}</ref> These studies, called project SSN20, were conducted during the [[Cold War]], when the Royal Navy maintained a strong emphasis on [[anti-submarine warfare]] to counter increasingly capable [[Soviet Union|Soviet]] submarines. To match this growing threat, the studies concluded that project SSN20 should be a revolutionary design, with significantly enhanced nuclear propulsion and firepower, and a more sophisticated "integrated sonar suite" and combat systems.<ref name="RAND"/> Similarly, the [[United States Navy]], which was facing the same threats, went on to design and build the {{sclass|Seawolf|submarine|4}}. The estimated costs of project SSN20, although great, were not considered a "constraint".<ref name="RAND"/>

However, by 1990 the [[Berlin Wall]] had fallen and the Cold War came to an end. Project SSN20 was promptly cancelled and a new set of design studies were started, this time, with "cost control" as a key objective.<ref name="RAND"/> The ''Trafalgar'' class had been an evolved derivative of the preceding ''Swiftsure'' class, and in order to reduce cost and technical risk it was concluded that this new class of fleet submarine should "build upon" the ''Trafalgar'' design. This became known as the Batch 2 ''Trafalgar'' class (B2TC), with approval for the studies phase given in June 1991.<ref name="RAND"/> While the philosophy behind B2TC was that of a modern and improved ''Trafalgar'', early design concepts of B2TC were also heavily influenced by the then under construction {{sclass|Vanguard|submarine|4}}, in particular its nuclear steam raising plant (NSRP).<ref name="RAND"/>