The OV1 (Orbiting Vehicle 1) were small research satellite to be launched piggy back on Atlas ICBM test flights. They consisted in general of the OV1 satellite and the OV1-PM propulsion module (or upper stage) to reach orbit.
The SM-65D Atlas, or Atlas D, was the first operational version of the U.S. Atlas missile. Atlas D was first used as an intercontinental ballistic missile (ICBM) to deliver a nuclear weapon payload on a suborbital trajectory. It was later developed as a launch vehicle to carry a payload to low Earth orbit on its own, and later to geosynchronous orbit, to the Moon, Venus, or Mars with the Agena or Centaur upper stage.
Convair, previously Consolidated Vultee, was an American aircraft manufacturing company that later expanded into rockets and spacecraft. The company was formed in 1943 by the merger of Consolidated Aircraft and Vultee Aircraft. In 1953 it was purchased by General Dynamics, and operated as their Convair Division for most of its corporate history.WIKI