Mark 45 torpedo

Mark 45 torpedo
Mark 45 torpedo

The Mark 45 anti-submarine torpedo (aka ASTOR) was a submarine-launched wire-guided nuclear torpedo designed by the United States Navy for use against high-speed, deep-diving, enemy submarines. The 19-inch (480 mm)-diametre torpedo was fitted with a W34 nuclear warhead: the need to maintain direct control over the warhead meant that a wire connection had to be maintained between the torpedo and submarine until detonation. Wire guidance systems were piggybacked onto this cable, and the torpedo had no homing capability. A joke at the time was "That the Mk-45 was the worlds only torpedo with a kill probability of 2! The target and the launching submarine!"[citation needed] There was absolutely no danger that the small nuclear warhead would damage the launching sub, even at less than half the normal range.[citation needed] The design was completed in 1960, and 600 torpedoes were built between 1963 and 1976, when ASTOR was replaced by the Mark 48 torpedo.



This electrically propelled, 19-inch (480 mm)-diametre torpedo was 227 inches (5,800 mm) long and weighed 2,400 pounds (1,100 kg).[1][2] The W34 nuclear warhead used in ASTOR had an explosive yield of 11 kilotons.[citation needed] [3] The requirement for positive control of nuclear warheads meant that ASTOR could only be detonated by a deliberate signal from the firing submarine, which necessitated a wire link. Because of this, the torpedo was only fitted with wire guidance systems (transmitted over the same link), and had no homing capability.[citation needed] The torpedo had a range of 6.2 to 8.5 miles (10.0 to 13.7 km).[2]at 40 Knots. By replacing the nuclear warhead and removing the wire guidance systems, the torpedo could be reconfigured for unguided launch against surface targets.[1]


Development of ASTOR was completed in 1960 and it entered service in 1963.[citation needed] Approximately 600 torpedoes were built by 1976, when the torpedo was replaced by the Mark 48 torpedo.[citation needed] The ASTORs were collected, fitted with conventional warheads and wake homing guidance systems, then sold to foreign navies as the Mark 45 Mod 1 Freedom Torpedo.[2]


  1. ^ a b Kurak (September 1966) p.147
  2. ^ a b c Polmar (November 1978) p.160
  3. ^ Preston, Anthony (1998). Submarine Warfare: an illustrated history. San Diego, CA: Thunder Bay Press. pp. 86. ISBN 1571451722. OCLC 40602917. 


  • Kurak, Steve (September 1966). The U. S. Navy's Torpedo Inventory. United States Naval Institute Proceedings. 
  • Polmar, Norman (November 1978). The Ships and Aircraft of the U.S. Fleet: Torpedoes. United States Naval Institute Proceedings.