This article is about the supersonic aircraft. For the music band, see SR-71 (band).
The Lockheed SR-71, unofficially known as the Blackbird and by its crews as the Habu, was an advanced, long-range, Mach 3 strategic reconnaissance aircraft developed from the Lockheed YF-12A and A-12 aircraft by Lockheed's Skunk Works (also responsible for the U-2 and many other advanced aircraft). The legendary "Kelly" Johnson, in particular, was the man behind many of the design's advanced concepts. The SR-71 was one of the first aircraft to be shaped to have an extremely low radar signature. The aircraft flew so fast and so high that if the pilot detected a surface-to-air missile launch, the standard evasive action was simply to accelerate. No SR-71 was ever shot down.
The A-12 Oxcart, designed for the CIA by Kelly Johnson at the Lockheed Skunkworks, was a precursor of the SR-71. Lockheed used the name "Archangel" for this design, but many documents use Johnson's preferred name for the plane, "the Article". As the design evolved, the internal Lockheed designation went from A-1 to A-11 as configuration changes occurred. The A-11 model was the first to fly as a test vehicle and was equipped with less powerful Pratt & Whitney J75s because development of the Pratt & Whitney J58s intended for the Oxcart was delayed. When the J58s finally arrived at the "Ranch" (Groom Lake's Area 51) and were installed as the 12th configuration change, the Article was renumbered the A-12, which it retained throughout production and operational usage. Eighteen were built, of which three were converted into YF-12As, prototypes of the planned F-12 interceptor version, and two were reconfigured as the M-21 variant (see below).
The Air Force reconnaissance version was originally called the R-12 (see the opening fly page in Paul Crickmoore's book SR-71, Secret Missions Revealed, which contains a copy of the original R-12 labeled plan view drawing of the vehicle). However, during the 1964 presidential campaign, Senator Barry Goldwater continually criticized President Lyndon B. Johnson and his administration for falling behind the Soviet Union in the research and development of new weapon systems. Johnson decided to counter this criticism with the public release of the highly classified A-12 program and later the existence of the reconnaissance version.