Royal Air Force Fylingdales or more simply RAF Fylingdales is a Royal Air Force station on Snod Hill in the North York Moors, England. Its motto is "Vigilamus" (translates to "We are watching"). It is a radar base and is also part of the Ballistic Missile Early Warning System (BMEWS). As part of intelligence-sharing arrangements between the United States and United Kingdom (see, for example, the UKUSA Agreement), data collected at RAF Fylingdales are shared between the two countries. Its primary purpose is to give the British and US governments warning of an impending ballistic missile attack (part of the so-called four minute warning during the Cold War). A secondary role is the detection and tracking of orbiting objects; Fylingdales is part of the United States Space Surveillance Network. As well as its early-warning and space-tracking roles, Fylingdales has a third function – the Satellite Warning Service for the UK. It keeps track of spy satellites used by other countries, so that secret activities in the UK can be carried out when they are not overhead. The armed services, defence manufacturers and research organisations, including universities, take advantage of this facility. History Cold War The station was sited on a former wartime mortar range on Snod Hill, which had to be comprehensively cleared by RAF Bomb Disposal before building could begin. The station was built by the Radio Corporation of America (RCA) in 1962, and was maintained by RCA (Great Britain), now Serco Group plc. RAF Fylingdales consisted of three diameter 'golfballs' or geodesic domes (radomes) containing mechanically steered radar. Operation of the Fylingdales Site transferred to RAF Fighter Command on 15 January 1964 although the site became operational on 17 September 1963. It became a local tourist attraction as a result. Between 1989 and 1992, Raytheon, the US defence contractor, completed a contract that saw the domes replaced by the current tetrahedron ('pyramid') structure, housing the AESA phased array radar. The site is above sea level and the structure is nine floors high rising from its ground level to high. National Missile Defence In the late 1990s, the United States decided to pursue a National Missile Defense plan fully, and RAF Fylingdales attracted further publicity. To improve tracking capabilities (for launches from Africa and the Middle East) the United States wanted the use of Fylingdales as part of its NMD network. After receiving a formal request from the US,