The Astute class boat is a submarine attack submarine that was commissioned by the Ministry of Defense for service in the Royal Navy (nuclear-powered attack submarine). The Swiftsure class of nuclear-powered attack submarines, which the Royal Navy commissioned between 1974 and 1981 and were thus getting close to the end of their operational lifespan, were the ones that this new vessel was intended to replace. In July of 1994, the Ministry of Defense sent out invitations to tender for the building of an initial three submarines, with an option for an additional two submarines to be built later. The selection of GEC-Marconi, which is now known as BAE Systems Marine, as the prime contractor took place in 1995.

The initial order was for a first batch of three submarines, as fixed in the original invitation to tender, but the Ministry of Defense later announced that it was planning a follow-on order for another three rather than just two submarines. The lead boat HMS Astute was commissioned with the US Navy in 2010. It was followed by the HMS Ambush in 2013. In 2016 a HMS Artful boat joined the Royal Navy. In 2021 the 4th boat of the class, the HMS Audacious was commissioned. By 2022 Royal Navy plans to operate a total of 7 Astute class boats. Four boats are already in service and three more are being built.

The performance specification for the Astute class submarines is essentially a development of that which characterizes the Trafalgar Batch 1 class boats operated by the 2nd Submarine Squadron from the Royal Navy’s base at Devonport. The design requirements included a 50 percent increase in ωεɑρσռs load and a significant reduction in radiated noise levels. The design matured into what was in effect a development of the fully modernized Trafalgar class submarine with a longer fin and two Thales (originally Pilkington Optronics) CM010 optronic periscopes whose masts do not penetrate the hull.

The Astute Batch 1 class submarines are to be named HMS Astute, Ambush and Artful, and were scheduled to enter service in 2008, 2009 and 2010 respectively, however the project was dragging behind the schedule. The electronic core of the submarines’ capabilities is the ACMS (Astute Combat Management System) developed by Alenia Marconi Systems as an improved version of the SMCS (Submarine Command System) in service with all current classes of British submarines. The ACMS receives data from the sonars and other sensors and, employing advanced algorithms and data handling, displays real-time images on the command consoles.

Factory acceptance of the operational software was received in July 2002. Tied into the ACMS is the WHLS (ധҽąքօղ Handling and Launch System) created by Strachan and Henshaw. The Astute class submarines have six 533 mm torpedo tubes. Their primary shorter-range ωεɑρσռs system are BAE Systems Spearfhish torpedoes and Boeing Sub-Harpoon anti-ship missiles. The Spearfish torpedo is a wire-guided ωεɑρσռ with active/passive homing and a range of 65 km at 60 kts. The Sub-Harpoon is a sea-skimming missile with high subsonic cruising speed, a range of more than 130 km and active radar terminal guidance.

Major long-range ωεɑρσռ systems, each carrying a high explosive rather than nuclear warhead, are the Raytheon Tomahawk Block IV land-attack cruise missiles. These missiles have a range of 1 700 km and can target enemy ships as well as land targets. The Tomahawk uses an internal navigation system with TERCOM (Terrain Counter Mapping) update for accurate long-range navigation. The Block IV missile having improvements such as upgraded propulsion, enhanced terminal guidance, and improved navigation through the installation of a GPC receiver.

There is capacity for a total of 36 torpedoes and missiles. Alternatively mines can be carried in place of torpedoes. The Astute class submarines are powered by Rolls-Royce pressurized water reactor. These reactors have a service life of 25 years and are not refueled. So the lead boat should reach the end of its service life in 2035. Range and sea endurance of these nuclear-powered attack boats are limited only by food supplies.

Initially it was planned that the first Astute class boats of the first batch will cost £2.23 billion per boat. That was around $3.5 billion. However construction went significantly over the planned budget and the actual completion cost was £3.35 billion ($5.24 billion) per boat. Construction cost decreased for the follow-on boats. Completion cost of the 4th boat ended up at £1.49 billion ($2 billion). In 2021 the US MoD awarded the BAE Systems and Rolls-Royce contracts for the design work for the successor of the Astute class. The new class of submarines should replace the Astute class boats starting from 2035 when the lead boat will reach the end of its service life.