Popular name for the U.S. low-altitude spy satellite that combined infrared, photo, and signals intelligence (SIGINT) capabilities.
First launched on June 15, 1971, by a Titan 3D booster, the Big Bird satellite weighed 15 tons, was 55 feet long, and housed two KH-9 series cameras that were able to distinguish objects as small as eight inches from an altitude of 90 miles. This was the first U.S. reconnaissance satellite that could photograph such small objects. Each camera had two film canisters to be parachuted to earth for aerial recovery.
Five of the Big Bird missions carried a third, aerial mapping camera with one film canister. Experiments were conducted in transmitting photos by radio signal, but that effort failed.
A ferret SIGINT capability was added to the basic camera satellite as a "hitchhiker."
The Big Bird satellites were launched at the rate of about two per year from 1971 to 1984; 19 successful launches were followed by one failure, on April 18, 1986, in which the booster exploded after takeoff. The Big Bird's major limitation was its relatively short life span, which started out at some 52 days; by 1978 it was extended to 179 days (the average orbital life was 138 days with a maximum of 275 days achieved in 1983).
The satellite was developed under the project designation Code 467. Its byeman name was Hexagon.
