U.S. Navy Reveals New Plan to Extend Range of Sub-Killing Torpedoes

Weapons engineers at Aerojet Rocketdyne are now tasked with improving the engine of U.S. Mark 48 heavyweight torpedoes. The Office of Naval Research awarded the company a $2.6 million contract to improve these Soviet-era weapons, which were designed during the Cold War to sink submarines at extremely low-depths as well as surface ships.

The U.S. Mark 48 torpedo was designed at the end of the 1960s during the height of the Cold War. It has received continuous upgrades throughout the decades. The swashplate piston engine on the rear of the missile is fueled by a monopropellant called Otto Fuel II. Thrust is generated by the propulsor assembly. (Image courtesy of the U.S. Navy.)

News of this contract comes on the heels of a $676.4 billion House Appropriations Committee bill, which was part of the annual defense authorization measure approved by the House last month after a quick midday meeting between the Pentagon and the House Appropriations Committee’s defense panel. This massive spending bill falls short of the defense budget request made by the White House in February by $1 billion. U.S. military weapons are going to receive a wholesale upgrade over the next couple of years as a result, which means companies like Aerojet Rocketdyne and the engineers they employ will get more business.

Why Extend the Range of the U.S. Mark 48 Torpedo?

The premise driving the request to extend the range of the U.S.Mark 48 torpedoes is simple: defer the communications workload of the torpedo’s targeting system to those of nearby aircraft. This allows the valuable submarine to keep a greater distance between the itself and its target.

With third-party targeting, the U.S. Mark 48 becomes a standoff weapon capable of attacking enemy submarines from an extended range, matching the capabilities of the surface Navy, which employs aircraft like the E-25 or F-35 to detect a hostile track using data captured by the surface ship, which can then counterattack and neutralize long-range missiles, like an SM-6. This gives the surface ships cover because they can leave their giant air radars off, instead relying on airborne sensors.

This is what a direct hit from a U.S. Mark 48 torpedo looks like when it hits a decommissioned U.S. destroyer during a training exercise. (Video courtesy of YouTube.)

But torpedoes travel through water, not air, and they do not reach high speeds. Increase their range, and the torpedoes take even longer to hit their targets. This means the U.S. Navy and Aerojet Rocketdyne face one important problem: how can they relay navigation updates to the torpedo’s targeting system?