Thor-Able

The Thor-Able was an American expendable launch system used for a series of re-entry vehicle tests and spacecraft launches between 1958 and 1960.

It was a two-stagerocket, consisting of a ThorIRBM as a first stage and a Vanguard-derived Able second stage. For satellite or space probe launches, an Altairsolid rocket motor was added as a third stage. It was a member of the Thor family and an early predecessor of the Delta.

The Able upper stage name represents its place as the first in the series, from the Joint Army/Navy Phonetic Alphabet.

The Thor-Able vehicle had a stronger airframe than the standard Thor IRBM and had the inertial guidance system replaced by a radio guidance package mounted on the Able stages.