Article snapshot taken from Wikipedia with creative commons attribution-sharealike license.
Give it a read and then ask your questions in the chat.
We can research this topic together.
Atlas-Able
The Atlas-D Able rocket carrying Pioneer P-3, sitting on Cape Canaveral's Launch Complex 14.
The Atlas-Able was an American expendable launch system derived from the SM-65 Atlas missile. It was a member of the Atlas family of rockets, and was used to launch several Pioneer spacecraft towards the Moon. Of the five Atlas-Able rockets built, two failed during static firings, and the other three failed to reach orbit.
The Atlas-Able was a three-and-a-half-stage rocket, with a stage-and-a-half Atlas missile as the first stage, an Able second stage, and an Altair third stage.
The first Atlas-Able used an Atlas C as the first stage, and was intended to carry Pioneer P-1, but exploded during a static fire test on 24 September 1959.
The remaining Pioneer launches used Atlas D missiles. Launches were conducted from Launch Complexes 12 and 14 at the Cape Canaveral Air Force Station. One launch was planned from Launch Complex 13; this became the second Atlas-Able to be destroyed during a static firing, and hence never launched.
This template lists historical, current, and future space rockets that at least once attempted (but not necessarily succeeded in) an orbital launch or that are planned to attempt such a launch in the future
Symbol indicates past or current rockets that attempted orbital launches but never succeeded (never did or has yet to perform a successful orbital launch)