carrier-capable.Pocock, Chris. "Lockheed U-2C/TR-1/U-2R/S." spyflight.com, 6 January 2008. Retrieved: 8 March 2009. U-2R/S details The U-2R, first flown in 1967, is significantly larger and more capable than the original aircraft. A tactical reconnaissance version, the TR-1A, first flew in August 1981. A distinguishing feature of these aircraft is the addition of a large instrumentation "superpod" under each wing. Designed for standoff tactical reconnaissance in Europe, the TR-1A was structurally identical to the U-2R. The 17th Reconnaissance Wing, RAF Alconbury, England used operational TR-1As from 1983 until 1991. The last U-2 and TR-1 aircraft were delivered to USAF in October 1989. In 1992 all TR-1s were re-designated to U-2R for uniformity across the fleet. The two-seat trainer variant of the TR-1, the TR-1B, was redesignated as the TU-2R. After upgrading with the GE F-118-101 engine, the former U-2Rs were designated the U-2S Senior Year. ER-2 details A derivative of the U-2 known as the ER-2 (Earth Resources 2), in NASA's white livery, is based at the Dryden Flight Research Center (now Armstrong Flight Research Center) and is used for high-altitude civilian research including Earth resources, celestial observations, atmospheric chemistry and dynamics, and oceanic processes. Programs using the aircraft include the Airborne Science Program, ERAST and Earth Science Enterprise. Landings are assisted by another pilot at speeds exceeding in a chase car. Operators United States Air Force Strategic Air Command 9th Strategic Reconnaissance Wing – Beale Air Force Base, California 1976–1992 1st Strategic Reconnaissance Squadron 1990–1992 5th Strategic Reconnaissance Training Squadron 1986–1992 95th Strategic Reconnaissance Squadron 1991–1992 (RAF Alconbury, UK) 99th Strategic Reconnaissance Squadron 1976–1992 4029th Strategic Reconnaissance Squadron 1981–1986 9 SRW Detachment 2; Osan Air Base, South Korea 1976–1992 9 SRW Detachment 3; RAF Akrotiri, Cyprus 1970–1992 9 SRW Detachment 4; RAF Mildenhall, UK 1976–1982 9 SRW Detachment 5; Patrick AFB, FL 1976–1992 17th Reconnaissance Wing – RAF Alconbury, UK 1982–1991 95th Reconnaissance Squadron 100th Strategic Reconnaissance Wing – Davis-Monthan Air Force Base, Arizona 1966–1976 99th Strategic Reconnaissance Squadron 1972–1976 (U-Tapao Air Base, Thailand) 349th Strategic Reconnaissance Squadron 1966–1976 1700th Reconnaissance Wing (Provisional) – Al Taif Air Base, Saudi Arabia 1990–1992 1704th Reconnaissance Squadron 4080th Strategic Reconnaissance Wing – Laughlin Air Force Base, Texas 1957–1966 4028th Strategic Reconnaissance Squadron Air Combat Command 9th Reconnaissance Wing – Beale Air Force Base, California 1992–present 1st Reconnaissance Squadron 1992–present 5th Reconnaissance Squadron 1994–present (Osan Air Base, South Korea) 95th Reconnaissance Squadron 1992–1993 99th Reconnaissance