CASTOR (A-21) class

 2 CASTOR-class SURVEY SHIPS (AGS)

 Name       Pendant No.   Launched        Commissioned    Status

 CASTOR     A-21          Nov. 5, 1964    Dec. 1, 1966    Stricken
 POLLUX     A-22          Nov. 5, 1964    Dec. 15, 1966   Stricken
 ANTARES    A-23          March 5, 1973   Nov. 21, 1974   Active
 RIGEL      A-24          March 5, 1973   Nov. 21, 1974   Active

The four ships then active were reclassified in 1986 from AH-21 through AH-24.