The site was originally dominated by 3 ‘Golf Balls’ which housed mechanical tracking radars. In the early 1990s, the old radars were replaced by a much more capable Solid State Phased Array Radar (SSPAR), which underwent another upgrade completed in 2007. The SSPAR was built by Raytheon and consists of a 3-sided truncated pyramid about 120 feet (40m) high. Each face is approximately 84 feet (28m) in diameter and contains an array of 2,560 transmit/receive modules, each with a circularly polarised ‘Pawsey Stub’ antenna. Each antenna has a power output of 340 watts and this gives an overall mean power output from the 3 faces of approximately 2.5 Mega Watts. The SSPAR has no big dishes that turn, indeed no moving parts at all. Instead, the SSPAR uses changes in electrical phase to steer the radar beam. Each of the 2,560 transmitters on a face can send out its pulse at a slightly different time – or more correctly in a different phase. These pulses combine together to form a wavefront which can be effectively pointed in any direction simply by altering the timing, or phasing, of the 2,560 transmitters. Although the use of this ‘phased array’ principle is well known and many radars now use this technique, Fylingdales is the only 3-faced BMEWS radar in the world, providing a full 360º of cover. The SSPAR can keep track of many hundreds of space objects per minute out to a range of 3000 nautical miles. The radar software is designed to ignore targets that do not behave like a rocket being launched or a satellite in orbit. It is little surprise, therefore, that RAF Fylingdales has never knowingly detected a UFO!