and a forward looking infrared turret under the starboard wing. Operational history Introduction to service The Nimrod first entered squadron service with the RAF at RAF St Mawgan in Cornwall in October 1969. These initial aircraft, designated as Nimrod MR1, were intended as a stop-gap measure, and thus were initially equipped with many of the same sensors and equipment as the Shackletons they were supplementing. While some improvements were implemented on the MR1 fleet to enhance their detection capabilities, the improved Nimrod MR2 variant entered service in August 1979 following a lengthy development process. The majority of the Nimrod fleet operated from RAF Kinloss in Scotland. Operationally, each active Nimrod would form a single piece of a complex submarine detection and monitoring mission. An emphasis on real-time intelligence sharing was paramount to these operations; upon detecting a submarine, Nimrod aircrews would inform Royal Navy frigates and other NATO-aligned vessels to pursuit in an effort to continuously monitor Soviet submarines. The safeguarding of the Royal Navy's Resolution-class ballistic missile submarines, which were the launch platform for Britain's nuclear deterrent, was viewed as being of the utmost priority. Falklands War Nimrods were first deployed to Wideawake airfield on Ascension Island on 5 April 1982, the type at first being used to fly local patrols around Ascension to guard against potential Argentine attacks, and to escort the British Task Force as it sailed south towards the Falklands, with Nimrods also being used to provide search and rescue as well as communications relay support of the Operation Black Buck bombing raids by Avro Vulcans. As the Task Force neared what would become the combat theatre and the threat from Argentine submarines rose, the more capable Nimrod MR2s took on operations initially performed by older Nimrod MR1s. Aviation author Chris Chant has claimed that the Nimrod R1 also conducted electronic intelligence missions operating from Punta Arenas in neutral Chile. The Chilean government allowed an RAF Nimrod R1 to fly signals reconnaissance sorties from the Desventuradas Islands, gathering information on Argentine Air Force movements. The addition of air-to-air refuelling probes allowed operations to be carried out in the vicinity of the Falklands, while the aircraft's armament was supplemented by the addition of 1,000 lb (450 kg) general-purpose bombs, BL755 cluster bombs and AIM-9 Sidewinder air-to-air missiles. The use of air-to-air refuelling allowed extremely long reconnaissance missions to be mounted, one example being a 19-hour 5-minute patrol