Supersonic torpedo

It operates through a multi-stage process. Once a submarine is detected, its location is relayed to the launch platform. SMART is fired from a canister-based launcher using a solid-fuel rocket motor. The missile then flies toward the target area, guided by an inertial navigation system and supported by mid-course updates through a two-way data link.

As it reaches the target area, the missile’s nose section separates and deploys a velocity reduction mechanism, including a parachute system, allowing the torpedo to reduce speed and enter the water safely.

Once released, the torpedo activates its onboard systems and begins an autonomous hunt, using acoustic sensors to search, track and strike the target submarine.

Stressing that submarine warfare occurs at close range even today, Commodore Abhay Singh (retired), a research fellow at the Manohar Parrikar Institute for Defence Studies and Analyses, said SMART seeks to engage submarines at extended ranges.

The weapon is designed to receive target information from maritime patrol aircraft, helicopters, unmanned systems, warships or other surveillance assets.

The system could prove to be vital for India as it faces a challenge from the growing presence of Chinese submarines and vessels in the Indian Ocean Region, and Pakistan inducting a Hangor-class submarine.

Singh said that underwater detection remains far more difficult than tracking surface ships or aircraft as even after a submarine is located, a weapon must still search for and engage a moving target underwater.

The challenge has grown as submarines themselves have evolved into bigger and more sophisticated systems.

“The submarines earlier had only weapons which were torpedoes. Now these are equipped with missiles, meaning the submarines themselves now have a standoff capability to launch,” Singh said, emphasising on the need for a standoff weapon system “to prosecute a submarine.”

Singh said that engaging submarines at a stand off range requires that they are tracked first, as long-range ASWs are only effective if “you have a long-range ASW surveillance capability in real time.”

“Fundamentally, your long-range ASW tools are your sonobuoys laid by your maritime surveillance aircraft,” he said, adding that unmanned aerial systems can also deploy and monitor sonobuoy fields to track and listen to submarine activity.

A sonobuoy is a small expendable sonar buoy dropped from aircraft or ships into the water to detect, classify, and track submarines.

Singh noted that SMART is built around a network-centric warfare concept, where the platform detecting the submarine need not be the one launching the weapon.

“Target data can come from somewhere else,” he said.

He added that the system’s mid-course update capability could improve accuracy against a moving target like a submarine.

However, experts caution that the weapon’s effectiveness will ultimately depend on its ability to overcome the challenges of tracking and engaging a constantly manoeuvring underwater target.

The DRDO did not respond to the programme’s status and the roadmap towards its induction in the Indian Navy till the time the story was sent for publication.

Captain Sarabjeet Singh Parmar, distinguished fellow at the New Delhi-based think tank United Service Institution of India and a retired naval officer, said that the central challenge in hunting a submarine is not distance but time.

According to him, ASW is a race between detection and engagement, where even a few minutes can determine whether a submarine is destroyed or not.

“The problem I foresee with this SMART system is that whatever distance you fire this thing from, it is going to reach the area much later. Every minute that is delayed means the submarine has chances to evade,” Parmar said.

He added that once a submarine is detected and positively classified, operators generate a firing solution by calculating the target’s position, movement, depth and likely course it is taking. These parameters are then programmed into the torpedo, which begins searching for the target after entering the water and switches to homing mode once it acquires the submarine.

Parmar said that the delay between detection and the torpedo’s arrival in the target area could give the submarine sufficient time to manoeuvre away from the predicted location.

“It is not a question of distance, it is a question of time. You can have 1,000 km or you can have 200 km. The question is how soon will the torpedo reach,” Parmar said.

He argued that helicopters, maritime patrol aircraft and warships carrying torpedoes may continue to offer advantages because they are already operating close to the suspected submarine’s location.

“If there is a helicopter or a P-8I (maritime surveillance aircraft) in the area, they carry their own torpedoes. Those, to my mind, are much better poised to prosecute because they are in the area,” Parmar said.

He explained that modern ships and aircraft can launch a torpedo almost immediately after getting the location, leaving less time for a submarine to alter course or disappear beneath the ocean depth.

The Indian Ocean presents its own set of challenges for ASW as its warmer waters create thermal layers that affect the way sound travels underwater, giving submarines an acoustic advantage over their hunters.

“The warmer the temperature, the thermocline or the way the sound moves is beneficial to the submarine, not to the ship,” Parmar said.

He added that the ability to react quickly after detection often matters more than the maximum range advertised for a weapon system in such an environment.

“The submarine will always hear the ship well before the ship can hear the submarine. That is why it is important that when you get submarine contact, you should be able to fire immediately”, Parmar said.

While the system marks an important leap for the navy, possibly providing long-range anti-submarine deterrent and the ability to engage hostile vessels far from the fleet, the question remains over how effectively such a capability can be employed effectively while racing against time and a moving target.