19" (48.3 cm) Mark 45
Ship Class Used On Submarines
Date Of Design 1957
Date In Service 1963
Weight Mod 0:  2,330 lbs. (1,057 kg)
Mod 1:  2,213 lbs. (1,004 kg)
Overall Length Mod 0:  225 in (5.715 m)
Mod 1:  227 in (5.766 m)
Explosive Charge Nuclear
Range / Speed 11,000 to 15,000 yards (10,000 to 13,650 m) / 40 knots
Power Sea-water Battery

Two solutions to the high speed, deep diving submarine problem were implemented.  The first was the nuclear warhead incorporated in the Mark 45 (ASTOR).  The torpedo itself was relatively conventional except for the use of a seawater activated battery to power a 160 hp electric motor.  Guidance was by a gyro, depth gear, wire combination using the attacking submarine's sonar to track the target.  There was no homing capability.  The warhead was detonated only by a signal sent along the wire; there was no contact or influence exploder in the torpedo.  The wire guidance and command detonation were not only important in getting the torpedo to the target, they also satisfied the requirement for positive control of the nuclear warhead.  Development of the Mark 45 was completed in FY60, it was approved for service use in FY61 and production deliveries began in FY63.  It was withdrawn from service in 1976 when the Mark 48 had demonstrated its capability and the advisability of using tactical nuclear weapons for ASW purposes became questionable.  The basic Mark 45 torpedo was modified by Westinghouse to make a conventional torpedo for foreign military sales, the so-called Freedom torpedo.  A few demonstration models were built but none were sold.