Introduction to UAV Systems by 
Military Robots and Drones by In the 1950s, the Battlefield Surveillance Department of the Army Electronic Proving Ground at Fort Huachuca began pursuing Unmanned Aerial Vehicles (UAVs), particularly the SD-1, for the photo surveillance mission. The SD-1 weighed 430 pounds, had a 12-foot wingspan and could reach airspeed of 228 mph, an altitude of 23,000 feet and stay aloft for one hour before being recovered by parachute.It was flown by a ground controller who tracked it on radar, sending it simple commands by radio. The SD-1 carried a KA-20A daylight camera or a KA-39A night camera.
This particular drone became known as “Old Faithful” after successfully completing 50 flights and parachute landings. More often, these drones would crash in the Arizona desert when their chutes failed to work properly. Training for the SD-1 was conducted by the US Army Combat Surveillance School Training Center at the US Army Electronic Proving Ground, Fort Huachuca.
The name SD-1, or “surveillance drone,” is actually the name of the whole drone surveillance system, including its ground equipment. The aircraft itself was called the RP-71 Falconer, made by Radioplanein 1955 as a derivative of the earlier series of target drones. The SD-1 t was replaced by the improved SD-2, and then by jet-powered models.