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 the Lockheed Skunk Works (also responsible for the U-2). It flew from 1964?1998. 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. Twelve aircraft are known to have been lost, all through non-combat causes.