In the late 1960s, NATO commanders recognized the need to provide an improved early warning and detection capability against the emerging low-altitude penetration threat posed by the Warsaw Pact. The most effective way to solve this air-defense problem is to use an airborne early warning (AEW) system that possesses radar with long-range and ìlook downî capability. The latter provides the ability to detect and track targets amidst the ground-clutter returns that degrade and confuse other air-defense radars. After a series of NATO-sponsored studies from 1971 through 1975, the Conference of National Armaments Directors selected the U.S. Air Force E-3 from the candidate AEW systems as offering the best operational solution. This led to establishment of a multinational provisional Airborne Early Warning and Control (AEW&C) Program Office by the NATO defense ministers in 1975. NATO then carried out a series of configuration, cost and performance studies that included the E-3 and its integration with the air-defense ground-environment systems. The intent was to maximize the "force-enhancing" effect inherent in these air-defense elements. The European environment required several modifications to the U.S. Air Force E-3, and these were combined with planned U.S. Air Force enhancements to form the basis of the "standard" configuration. The program featured a single development program, with both the U.S. Air Force and NATO utilizing the same basic configuration. This provided economies of production and met the objectives of industrial collaboration, standardization and interoperability. In 1978, development was initiated on the standard-configuration E-3 by the alliance, while the national governments performed an in-depth review of the proposal and came to an agreement on acquisition and cost-sharing arrangements. The defense ministers met in December 1978 and signed a multilateral memorandum of understanding to acquire a NATO-owned Airborne Early Warning and Control System. The NATO AEW&C Program Management Organization (NAPMO) was established to manage the acquisition program of the 18 aircraft and supporting equipment and trainers. Additional NAPMO responsibilities included modifying the NATO air-defense ground-environment system necessary to provide data exchange and interoperability; activating the Main Operating Base at Geilenkirchen, Germany, and other operating facilities in northern- and southern-flank nations; constructing maintenance and repair facilities at the MOB; and establishing a training center to assist the multinational force that operates the NATO E-3 fleet. This office continues to manage the modernization of the NATO aircraft and supporting elements. AWACS Configuration The NATO E-3 was built upon the successfully developed and deployed U.S. Air Force E-3. The original U.S. Air Force E-3, often referred to as the "Core E-3," uses an electronically sophisticated radar able to detect high- and low-flying aircraft. Its range extends beyond 400 kilometers when the E-3 is flying at 9,000 meters, and its surveillance volume is scanned by the identification friend or foe (IFF), thus providing a means of sorting friendly from hostile aircraft. The antennas for both of these mission systems are housed in a 9.1-meter-diameter rotating radome that is carried atop the AWACS. The structure rotates every 10 seconds, providing 360-degree surveillance coverage. Coupled with the modern surveillance systems are extensive avionics equipment for navigation, communications, data processing and display. These are integrated into a Boeing 707-320B, modified to accommodate the mission equipment and crew of 17, and powered with four Pratt & Whitney TF-33 turbofan engines. Standard Configuration All NATO and U.S. E-3 systems delivered in and after December 1981 were in the "standard" configuration. This configuration built upon the core E-3 by enhancing the radar not only to detect airborne targets in clutter, but also to detect maritime vessels operating in such areas as the North Sea and Mediterranean Sea. The already versatile communication links on the E-3 were improved further by the addition of the newly developed JTIDS (Joint Tactical Information Distribution System). JTIDS allows a large volume of information to be transmitted in seconds to many users. The system uses special technology and techniques for protection against electronic jamming and enemy eavesdropping. Additionally, the AWACS computer was enhanced to increase capacity and speed. This allows the operational computer programs to expand their functions and to provide increased track-handling and communications processing. The first standard E-3 was delivered to the U.S. Air Force in December 1981 after an extensive test and qualification period. NATO took delivery of its first production E-3 in January 1982. The 18th system was delivered April 25, 1985, ahead of schedule and below the contract price agreed upon five years earlier. Improvements Since its initial deployment, the E-3 has been continually modernized to meet its evolving mission requirements. Boeing was awarded a U.S. Air Force contract in May 1987 to begin a long-term improvement program for the AWACS. The largest effort of this integration contract (ICON) will be full-scale development and integration of an Electronic Support Measures (ESM) system into U.S. and NATO E-3s. The ESM system will reduce the risk of attack by allowing the E-3 to detect signals emitted by both hostile and friendly targets and to help identify them. ESM represented the first system upgrade to the NATO E-3 fleet and was the first U.S. Air Force/NATO cooperatively developed E-3 enhancement. In January 1993, Boeing was awarded a $294.6 million contract for the Mod Block 1 phase of the NATO E-3 modernization program. Under this contract, Boeing, with subcontractor support, worked on the design, integration, production and installation of three major enhancements: new color displays improve the form and usability of incoming situational information and Have-Quick radios add secure and anti-jam features to the UHF communication system. A version of the JTIDS, called Link 16, increases the amount of information that can be collected and shared between two AWACS allied aircraft. Boeing completed trial installation of Mod Block 1 equipment in February 1995. In November 1997, the Boeing Operations International (BOI)/Daimler-Benz Aerospace (Dasa) team in Manching, Germany, completed retrofit of all 17 E-3 aircraft with Mod Block 1 and ESM systems. NATO also has joined the Radar System Improvement Program (RSIP), a multinational cooperative effort. RSIP will improve the E-3ís radar by increasing the sensitivity of the pulse Doppler radar so the aircraft can detect and track smaller stealthy targets over a longer range. It will also improve the radarís electronic counter-countermeasures capability (making it harder to jam the system), upgrade the radar operatorís console, replace the radarís existing computer with a new high-reliability multiprocessor and rewrite the radar software to make it easier to maintain and enhance in the future. RSIP Initial Operation Test and Evaluation (IOT&E) flight testing on board a NATO E-3 was completed in September 1996. Later that year, Boeing was authorized by the U.S. Air Force, NATO and the United Kingdom to begin production of radar enhancements to their AWACS fleets. The installation of NATO kits began in late 1997 by the BOI/Dasa team. Retrofit of all 17 aircraft will be completed in 1999. In November 1997, Boeing received a contract worth approximately $450 million to develop and test the next mission systems upgrade for the NATO E-3 fleet. Under the Mid-Term engineering, manufacturing and development (EMD) contract, which runs through 2001, Boeing -- supported by subcontractors from participating NATO nations -- will integrate major system-related enhancements to computers, displays, communications, navigation and target identification. Retrofit of the entire fleet will be implemented during a follow-on contract. Studies currently are under way to define the next phase of NATO AWACS enhancements, which will enable the alliance to respond to changing missions and the political environment in the European Theater. NATO and U.S. E-3 Specifications