During firing of the apogee kick motor, contact was lost with the satellite. Syncom (Synchronous Communications) was a NASA project supported by DoD ground stations and communications experiments. Spacecraft engaged in practical applications and uses of space technology such as weather or communication (US Cat C). Four score. Last known longitude (10 March 1987) 172.58 deg E drifting at 2.429 deg E per day.

NASA's Syncom II synchronous communications satellite was placed in orbit by a Thor/Delta launched from Cape Canaveral. Experimental commsat; first geosynchronous satellite. Spacecraft engaged in practical applications and uses of space technology such as weather or communication (US Cat C). Positioned in geosynchronous orbit at 55 deg W in 1963; 26 deg W in 1965. Last known longitude (19 July 1995) 68.47 deg E drifting at 0.089 deg W per day.

NASA's Syncom III synchronous communications satellite was launched into orbit by a Thrust Augmented Thor/Delta (TAD) launch vehicle in its first use as a space booster. Also carried Star Flash experiment. Spacecraft engaged in practical applications and uses of space technology such as weather or communication (US Cat C). Positioned in geosynchronous orbit at 64 deg W in 1964; 180 deg E in 1964; 25 deg W in 1965; 165 deg E in 1966-1969. Last known longitude (6 December 1974) 6.08 deg W drifting at 0.188 deg W per day.

The Defense Department began military communications experiments between Saigon, Republic of South Vietnam, and Hawaii using the Syncom II synchronous communications satellite. These Saigon-Hawaii experiments further extended the Defense Department's usage of Syncom II that had begun several months earlier.

The transfer of Syncom II and III from NASA to the Defense Department was completed. The Defense Communications Agency (DCA) directed their use, but the Air Force Satellite Control (AFSCF) and its operating locations in the Pacific and Indian Oceans maintained precise control and positioning of the two synchronous communications satellites. The Army and Navy were responsible for the ground communications facilities that were used with the Syncom satellites.