 The final Atlas-Agena launch used an Atlas E/F.The earliest Agena variant was the Agena A in 1959-60, which did not have restart capability.Most of these were flown on Thor-Agena boosters for the Discoverer program and only four used Atlases (Midas 1, Midas 2, Samos 1, and Samos 2), two of which failed.