Thor-Delta

Thor-Delta, also called Delta DM-19 or simply Delta, was an early American expendable launch system used for twelve orbital launches in the early 1960s. It was a derivative of the Thor-Able and a member of the Thor family of rockets, and it was the first member of the Delta family. The first stage was a Thor missile in the DM-19 configuration, the second stage was the new Delta stage with an AJ-10-142 engine derived from the earlier Able stage, and an Altair solid rocket motor served as a third stage. The Delta stage added cold gas attitude control jets so it could be stabilised in orbit for restarts and more precise burns. Its payloads included Echo 1A, the first communications satellite, Ariel 1, the first British satellite, and Telstar 1, the first active direct-relay communications satellite. All twelve launches flew from Cape Canaveral, and all succeeded except the first, which failed to place Echo 1 into orbit.