The Lockheed A-12, produced from 1962 to 1964 at the Skunk Works in Burbank, California, made its first flight at the Groom Lake test facility at Area 51 on April 25, 1962.
The aircraft was made mostly of titanium, with radar-absorbing composite materials added on. The A-12 was based on designs by Clarence “Kelly” Johnson.
Commissioned by the CIA, it bridged the gap between the U-2 program and the conversion to satellite surveillance. It was the 12th in the “Archangel” design series. The A-12 was sometimes called “Oxcart,” the code name for the program, but crews called it the “Cygnus.”
Advances in Soviet tracking and missile technology put the A-12 at risk. The program was ended in December 1966.