"Viking (first model)" . . "1" . "Viking 1" . . "12" . "Viking rockets" . . "Viking 4" . "Viking 2" . . "Viking rocket" . "7" . "1949-05-03" . "Viking (rocket)#Design features" . . "1" . "RTV-N-12a Viking sounding rocket" . "Viking (rocket)" . . "Viking 3" . . "''Viking I'' (rocket)" . "4" . "RTV-N-12 Viking" . . "Viking 10" . "Viking 12 sounding rocket" . . "Viking (rocket)" . . "Retired" . . "Viking" . "Viking (second model)" . . . . "Viking 5" . . "Viking 6" . "1955-02-04" . . . . "RTV-N-12a Viking" .