OSCAR 3 was the first active amateur radio satellite, that he was endowed with a linear transponder. He was also the first amateur radio satellite with solar cells.

The satellite was launched on 9 March 1965 as secondary payload along with seven satellites of the U.S. Air Force with a Thor - Agena rocket at Vandenberg Air Force Base. The transponder was 18 days in operation, the two beacons sent several months. The uplink and downlink were both in the 2- meter band.

OSCAR 3 followed the first active communication satellite Courier 1B (1960 ) and the first active civilian communication satellites Telstar 1 (1962). The first two-way communication via amateur radio satellite came a day after the launch between a ham radio operator in Germany (Alfons Häring, call sign DL6EZA ) and Switzerland (Hans -Rudolf Lauber HB9RG ) in Morse code about. The first connection in radio also (Karl Meinzer DJ4ZC and HB9RG ) took place between these countries.

His COSPAR designation 1965 - 016F.