The Lockheed SR-71 Blackbird first flew in 1964 and entered service in 1966. Designed by Kelly Johnson’s Skunk Works, it cruised at Mach 3.2 at 85,000 feet—higher and faster than any interceptor or surface-to-air missile of its era. If a missile launch was detected, the standard procedure was to simply speed up. On July 28, 1976, an SR-71 set absolute records for altitude (85,069 feet) and speed (2,193 mph, Mach 3.3) that still stand. The aircraft was built largely of titanium to withstand skin temperatures reaching 600°F. Its fuel tanks were designed to leak on the ground until thermal expansion sealed them in flight. Thirty-two were built; twelve were lost to accidents, none to enemy action. The program was retired in 1990, briefly revived in the mid-1990s, and finally closed in 1998.