Today, submarines have no way to defend themselves against air threats. Submarine forces worldwide have an increasing need to operate close
to shores in shallow waters. (As an example during the campaign in Libya, submarines were conducting intelligence missions close to shores). In such situation submarines are an easy target for helicopters and maritime patrol aircraft (MPA). When detected in shallow waters, there is no possibility for the submarine to escape, contrary to deep sea where they can employ various tactics and disappear. Up until now, submarines were harmless against air threats, while significantly cheaper and less complex naval platform like small Fast Attack Craft (FAC) may be fitted with a SAM solution.
It is this gap that DCNS and MBDA are looking to fill. The doctrine of use is not for the submarine to attack first. The submarine will keep trying to escape when faced with an air threat as it has always been the case. However the submarine will shoot it down if escape is not possible.
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For target designation, the submarine crew needs some of the following data from the target: its bearing, its range, its speed or its course. When submerged the crew will use acoustic detection to acquire this data. If faced with a helicopter with dipping sonar, the crew will get its bearing, its speed (virtually 0) and its approximate altitude which is enough aquire the target with accuracy. If faced with an MPA, the crew will know a threat is in the area. If the submarine is detected it will employ tactics to go to periscope depth and acquire the MPA with its optronics systems.
This is all consistent with current submarine missions: When a helicopter dips its sonar, its behavior is considered aggressive by the submarine. Same thing when a MPA detects the submarine thanks to its active sonobuoys.
DCNS offers two solutions to give the choice to its customers. The mast version has shorter range but doesn't impact the maximum payload of the submarine. It is the suggested choice for smaller platforms such as the Andrasta which has provision for only 6 weapons. The mast version would actually increase the payload of Andrasta.
There are no US submarines that carry any sort of anti-aircraft missle. The Germans are developing an anti-helicopter missle for their new class of diesel boats (IDAS) and the US did test an anti-aircraft (helicopter) missile a long time ago and abandoned it. I think it was called SLAAM - submarine Launched Anti-Aircraft Missile - and it was launched vertically from the sail near where the periscopes come out.
With anti-aircraft missiles, you'd need a radar to find and track targets - submarines don't carry that sort of radar (just surface search radar). An encounter between a submarine and an anti-sub helicopter would almost always be fatal to the sub, unless the conditions we such that the sub could "hide" in a temperature gradient under the sea that prevents the helo dipping sonar from finding it. Helo's also carry magnetic detectors that can localize a submarine very precisely underwater. The SLAAM missile was sort of a last ditch attempt to destroy a helo with a heat seeking missile launched from a sub. Might have worked on the first helo, but I think I'd run or hide as a better approach.
Anti-ship missiles on submarines have very long ranges - both the encapsulated Harpoon missile and the Tomahawk Anti-Ship variants - can attack ships well beyond the range of the subs owns sensors. Those weapons mostly depend on Over the Horizon targeting to give the sub coordinates of ships to attack with these types of weapons. Those targets may be important to the safety of a battle group, but probably don't directly threaten the launching sub itself.
The US submarine fleet (attack subs) are primarily an anti-submarine weapon. While their torpedoes and anti-ship missiles can easily disable or destroy a surface ship, their sensors are not optimized to detect these targets precise enough for attach with anti-ship missiles. Most submarines now also carry Tomahawk land attack missiles as well, designed to attack land targets from very long ranges when provided with targeting coordinates via radio link. These weapons are carried for launch in horizontal torpedo tubes and the vertical launch tubes carried just outside the pressure hull forward on some newer SSN and converted OHIO class (former Trident) SSBNs.
IDAS (Interactive Defence and Attack System for Submarines) is a short-range missile currently being developed for the new Type 212 submarine class of the German Navy.
IDAS (based on the IRIS-T air-to-air missile) is primarily targeted against air threats, such as ASW helicopters, but also against small or medium-sized surface vessels or coastal land targets. It is currently being developed by Diehl BGT Defence and HDW, which is a part of thyssenkrupp Marine Systems (TKMS), to be fired from Type 212's torpedo tubes. IDAS will be fibre-optic guided and officially has a range of approx. 20 km.[2] Four missiles will fit in one torpedo tube, stored in a magazine. First deliveries of IDAS for the German Navy and operational service were planned from 2014 on.[3]
The IDAS system is also the world's first missile which gives submarines the capability to engage air threats whilst submerged, and the first tube-launched missile that does not emerge in a capsule, but is fired directly from the torpedo tubes.
Alternatively, IDAS could be in theory fired from the Gabler Maschinenbau TRIPLE-M mast system, but, at least in the new Type 216 submarine currently under development, IDAS will be fired as normal from the torpedo tubes, while the Muraena will be the primary weapons option for its TRIPLE-M system.
On May 2013, the Turkish company Roketsan and the German IDAS Consortium formed by thyssenkrupp Marine Systems and Diehl BGT Defence signed a cooperation agreement to develop and supply the submarine-launched IDAS (= Interactive Defence and Attack System for Submarines) missile.
The underwater vehicle version comprises a torpedo-like capsule (the VSM) containing a medium-range (20 km) Mica missile that is tube-launchable at any depth. The capsule is similar to the type developed for submarine-launched SM 39 Exocet anti-ship missiles, a proven system which exists for 35 years now. The missile is based on VL Mica (launched from surface vessels) which has already been procured by several navies. MICA covers Beyond Visual Range situations offering additionally 2 guidance systems with its 2 interoperable seekers:
• RF MICA with radar seeker providing all weather shoot-up / shoot down capability
• IR MICA with dual waveband imaging infrared seeker
VL Mica has a range of up to 20 Km and reaches speeds in excess of Mach 3. A3SM underwater vehicle version with Mica missile can be considered a medium range solution to be deployed when submerged.
For submarine launch, MBDA selected the IR version because of the characteristics of the threats: Helicopters and MPAs have low Doppler signature and IR is a better match against these types of targets. The 12 Kg warhead of the Mica guarantees a "full kill" capability against both types. Fitted with thrust vectoring, Mica has very high maneuverability (proven against anti-ship missiles) which leaves little to no escape opportunities for slow moving targets such as ASW helicopters and MPAs. The thrust vectoring of Mica allows it to be fired when the submarine is cruising away from the threat. In addition the VSM (torpedo-like capsule holding the Mica) is powered by a rocket engine and has the ability to maneuver underwater, meaning the Mica may attack its target from any angles and catch the helicopter or MPA crew off guard.
The VSM was adapted to provide the same launch environment as when a VL Mica is launched from a vertical launch system. All the other steps (launch from the submarine, underwater step, breach of the surface and air step) remain exactly the same as for the SM39 therefore are already validated. MBDA basically merged 2 existing concepts into a single one: SM39 + VL Mica. The only modifications are found inside the VSM. Some adaptation work was conducted to fir the Mica which is a smaller missile than Exocet. The other focus is behavior at the launch: Mica accelerates very quickly therefore exhaust gas management is different.
The mast version comprises a missile housing (that remains watertight throughout the submarine’s operating range and down to maximum diving depth) mounted on a hoistable mast and containing three short-range MBDA Mistral 2 missiles that can be fired from periscope depth. DCNS is in charge of developing the launching system. Mistral 2 is a lightweight, fully digital, heat seeking missile with a maximum range of 6.5 Km and maximum speed of Mach 2.5. An Infra-Red camera from SAGEM is fitted in the missile housing to act as optronic aiming sight. A3SM Mast version with Mistral missile can be considered a short range solution to be deployed from periscope depth.
Contrary to Mica missile, the Mistral requires to be locked on target before launch. The Mistral's homing guidance with an infra-red seeker is reported to be the best solution against helicopters and MPAs. A3SM mast version may shoot on the move and in any directions which is an important feature as reaction time is key for self defence. Thanks to its compact nature (less than 20 Kg, less than 2 meters) three Mistrals can be fitted in the mast. When back in port, the whole canister may be replaced by a new one. Loading of the Mistrals in the canister occur in a dedicated facility.
Mistral is fitted on most vessels of the French Navy, from the aircraft carrier to patrol boats. It has shown its capability against many types of targets: anti-ship missiles, helicopters and fast jets. MBDA has extensive experience integrating the Mistral on many platform and launchers (fixed, vehicles, helicopters, ships...) and see no difference in integrating the Mistral to the DCNS launcher. DCNS goal with the existing mast.
A3SM: A Game changer
DCNS and MBDA insist there is no missile development required as both missiles are already proven solution, which significantly reduces risk and cost. Both versions will be fully integrated with Subtics combat systems.
DCNS and MBDA already submitted offers to several potential customers and stand ready to finalize the development once they get a contract. They estimate it could take as little as 2 to 3 years between contract signature and IOC.
A3SM weapon systems for submarines can be considered a game changer because the rules of anti--submarine warfare are indeed about to change. While submarines will certainly not start conducting anti--helicopter or anti-MPAs patrols, they will soon have means to take action and defend themselves in case of absolute necessity while in the past ASW helicopters and MPAs could keep on engaging a detected submarine over and over again without fear of retaliation. A3SM will act as deterrence for submarines and keep ASW helicopters and MPAs at bay in the near future
Other more elaborate concepts exist where short-range air-to-air missiles are mounted inside existing cruise missile designs. The submarine launches the missile which then performers a pre-selected low-level patrol pattern in the area of the submarine, giving it a form of top cover. If its radar or electronic sensor suite picks up an aerial contact, it pursues it and launches missiles at it.
Although this type of concept is highly intriguing, it is also very expensive, complex and calls into question the ethical issues of unmanned weapon system autonomy that the DoD is struggling with today. Not just that but the presence of the missile is a great sign that an enemy submarine is nearby. There are no clear indications that this type of submarine-launched counter-air capability is actively being developed at this time, but that could change considering how the marketplace is evolving.
Pros and cons
There’s clearly development and investment within the global defense industry for SLAM systems, so there has to be a strengthening demand for them right? Well, don't consider the case for them to be overwhelming. Think of these systems as a last line of defense for submarines that have been located, and are facing imminent death from an aerial asset above. Using them as an offensive weapon is highly unlikely and tactically bankrupt in almost all circumstances.
This is especially true for systems like the A3SM, which require the sub to come very near the surface for a shot on a helicopter operating low, slow, and relatively close by. This leaves the submarine vulnerable, and likely results in a showdown between the ASW aircraft and submarine itself—one in which the first to fire might be pulling the trigger on a major conflict as well.
There is also the question of if naval commanders would want this type of weapon on their submarines at all, as it gives a submarine commander a possible out once detected. The whole idea of submarine warfare centers around not being detected in the first place—such a weapon system may have a hard time fitting into that proven concept of operations.
Who needs it most, if anyone?
So are submarine-launched air missiles really a capability we’ll find widespread on submarines in the future? Maybe: But there will be a clear delineation in the motives of the countries that deploy them.
These systems might prove most valuable on diesel-electric submarines, especially those that are not air-independent propulsion (AIP) equipped, and have to surface far more often to recharge their batteries. With the window for undersea operations narrowed, a SLAM at least gives air-breathing subs a shot at defending themselves from an imminent attack.
These boats spend much of their operational careers close to shore in littoral combat environments where hiding places are prevalent, but once detected, escape options may be limited. But even then, SLAMs would be a weapon of last resort—used under extreme circumstances due to its massive implications.
Another hindrance is that diesel electric subs have less space for weaponry and sensor masts than their larger and more complex nuclear counterparts. Taking up valuable real estate with a questionable last line of defense weapon may prove unpalatable. IDAS, with its potential land and surface attack capability, would at least exchange multi-role flexibility for the space it takes up and the cost of integration and training.
Considering China’s large fleet of diesel-electric submarines, shallow operating areas in the South China Sea, and the prevalence of American, Japanese and other navies in the region operating high-quality anti-submarine warfare capabilities, a Chinese SLAM may become a reality in the near future. In fact, the PLAN has worked on various submarine-based anti-aircraft weapons concepts in the past.
Photo via AP
Israel’s Dolphin class diesel-electric boats are used as second-strike nuclear deterrents when outfitted with nuclear-tipped Popeye Turbo cruise missiles. During these patrols, it’s the boat’s job to go hide for long periods of time. Leveraging AIP technology, they can do this for days or even weeks at a time. Considering they could be called upon to enact nuclear revenge at any moment, adding a counter-air missile to their quiver may be just a logical step in ensuring that their mission will succeed, no matter the circumstances.
Nuclear submarine-equipped countries like the UK, France and especially the US may end up fielding SLAMs—or they may already have—because it’s just another integrated capability to have at the submarine commander’s fingertips. These boats cost billions of dollars each. Spending a comparatively small amount on additional capabilities, even capabilities with very narrow use, is not out of the question, especially since we already spend billions on other capabilities that have a low probability of use. Also keeping in mind where these big stealth vessels go, having a new tool to get away alive from a prowling ASW helicopter may be a better solution for a boat filled with a nation’s most guarded military technology secrets than getting sunk deep in enemy territory. Finally, there’s more room on these boats to deploy new capabilities compared to their relatively tiny diesel-electric cousins. Giving up one vertical launch tube—if even that—for a submarine derringer pistol of sorts is not such a huge sacrifice.
http://www.navyrecognition.com/index.php?option=com_content&view=article&id=1100
