The ATDA (Augmented Target Docking Adapter) had been prepared as a back-up target in case of an GATV (Gemini Agena Target Vehicle) failure. The ATDA was a short cylinder consisting of a target docking adapter cone mounted on front and containing a communications system, a guidance and control system, and a reaction control system. It also had running lights, but unlike the GATV, the ATDA had no propulsive capabilities for orbit changes.
The Atlas SLV-3, or SLV-3 Atlas was an American expendable launch system derived from the SM-65 Atlas / SM-65D Atlas missile. It was a member of the Atlas family of rockets.
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