their own stealth aircraft is a telling indication of just how giant a step the development of stealth represented.
Rotary Wings and UAVs Less well known, but equally successful, was DARPA’s work on no-tail-rotor (NOTAR) helicopter technology. The agency’s support helped Hughes Helicopters mature the NOTAR concept and show its operational advantages with the NOTAR flying demonstrator in 1981. This led to a NOTAR series of military/ commercial helicopters from McDonnell Douglas after it acquired Hughes Helicopters in 1984. In 1984, DARPA began a rapid prototype program that produced the world’s first long-endurance unmanned aerial vehicle, the Amber UAV, which
DEFENSE ADVANCED RESEARCH PROJECTS AGENCY I 60 YEARS
in 1988 flew for 38 hours continuously. The technology pioneered with Amber led to the famed medium-endurance MQ-1 Predator UAV. A decade later, two more unmanned X-plane programs were up and running with DARPA support. Lockheed Martin’s RQ-3 Dark Star was developed for DARPA’s requirement for a low-observable high-altitude long-endurance (HALE) UAV. A highly survivable intelligence, surveillance, and reconnaissance (ISR) platform, Dark Star’s technology contributed to the design of the stealthy Lockheed Martin RQ-170 Sentinel, famously dubbed the “Beast of Kandahar.” The RQ-4 Global Hawk also originated as a DARPA high-altitude long-endurance program in 1994. The agency issued an Advanced Concept Technology Demonstration contract to Teledyne Ryan Aeronautical (later acquired by Northrop Grumman) in 1995, which produced several RQ-4 prototypes. The system transitioned directly to operations with the USAF. Air Vehicle Number 3 from the demonstration program flew thousands of hours of combat missions over Iraq. The demonstrator flew just 3 percent of the imagery intelligence missions over Iraq, but located 55 percent of the time-sensitive targets generated to destroy air defense equipment.
NASA PHOTO BY CARLA THOMAS
CLOCKWISE FROM TOP: Tacit Blue employed second-generation stealth shaping and materials to enable a battlefield reconnaissance and surveillance aircraft to operate near the forward edge of the battlefield with a high degree of survivability; DARPA’s Amber UAV was the world’s first long-endurance UAV, and led to the famed Predator UAV; the RQ-3 Darkstar was developed to a DARPA requirement for a low-observable high-altitude long-endurance UAV, and contributed to later stealthy UAV designs; the beginning of it all was Have Blue, the prototype for the first stealth aircraft. Note the early inward-canted twin tails, later modified to outward-canted tails on the F-117.