[3] A derivative of the Thor-Delta, it was a member of the Delta family of rockets.

[4] An Altair solid rocket motor was used as a third stage.

[1] All nine launches occurred from Cape Canaveral Air Force Station Launch Complex 17.

[3] Most of the launches carried communications satellites, including Syncom-1[2] and Syncom-2.

[5] Syncom-2 subsequently became the first geosynchronous satellite,[5] and was placed at 55° west of the Greenwich Meridian.