Atlas-Agena

The Atlas-Agena was an American expendable launch system derived from the SM-65 Atlas missile and a member of the Atlas family of rockets that Convair built. It was launched 109 times between 1960 and 1978. A stage-and-a-half Atlas missile served as first stage, topped by an RM-81 Agena second stage, so it counted as a two-and-a-half-stage rocket; the early flights used Atlas D missiles redesignated LV-3, which were later replaced by the standardised Atlas SLV-3 and its SLV-3A and SLV-3B derivatives, and the final launch used an Atlas E/F. It launched the first five Mariner probes to Venus and Mars and the Ranger and Lunar Orbiter probes to the Moon, and its Agena stage served as the uncrewed target vehicle on which Gemini crews practised rendezvous and docking, although most launches carried classified Defense Department payloads. Launch sites were Cape Canaveral Launch Complexes 12, 13 and 14 and Point Arguello, now Vandenberg Space Launch Complexes 3 and 4.