July 29, 2015

Submarine Launched Airflight Missile (SLAMs)

There are many emerging technologies that could be placed in or on a submarine. One technology is Submarine Launched Airflight Missile (SLAMs) or Submarine SAMs. These may normally be intended for SSK use but they may also be on Russian SSNs.

Unlike torpedos SLAMs have generally not been seen as essential equipment. Projects to develop SLAMs have risen and fallen for at least 45 years. In 1972 the UK tested a Blowpipe SLAM system on HMS Aeneas (P427) in 1972. This consisted of a cluster of four missiles on a mast that  could be raised from a submarine's sail/fin. This system was then installed on an Israeli Gal class (modified UK built HDW 206) submarine.

Reasons why SLAMs have not been adopted may include difficult and slow operation making for low effectiveness and need for the submarine to expose itself to the attacking helicopters or maritime patrol aircraft (MPAs). However advances in SLAM technology may be making them a more worthwhile inclusion in a submarine.

Factors that may encourage submarine captain to use a SLAM include:

-  whether it is a wartime emergency situation where the submarine has been detected, or detection is imminent, by a helicopter/MPA? Detection might be by helicopter dipping-active sonar or fixed wing maritime patrol aircraft (MPA) dropped sonobouy.

-  whether the SLAM can be deployed in such a way that minimises submarine exposure? 

-  could increasing long range, or stealthier, SLAMs be arguments for greater use?

-  by what mode is the missile deployed?
   :  from a mast or the sail (likely to lead to detection of sub)
   :  float-up container or
   :  by missile carried by torpedo (may be quickest method and less likely to lead to sub's detection)

-  how quick is that mode? (the quicker the better to defeat the helicopter/MPA's actions or countermeasures).

-  does the SLAM armed submarine (eg. a Kilo)  have a major anti-aircraft role in support of other higher value submarines (eg. SSBNs)? 

-  does the missile carry added benefits/fuctions like anti-missile, anti-shipping or light land attack capabilities?

France and Germany have been marketing SLAM solutions. Russia is thought to have developed Strela-3 and Igla SLAMs and no doubt US companies have developed SLAM ideas at times.  It is difficult to gauge how mature the technologies are.

DCNS has been marketing a mast launched Mistral SLAM concept known as A3SM (above). The Mast version comprises a missile housing (that remains watertight throughout the submarine’s operating range and diving depth) mounted on a hoistable mast and containing several short-range Mistral missiles that can be fired from periscope depth. 

A mast mounted MICA missile has also been tested but slower reaction-vulnerability shortcomings of the mast mounted concept were apparent.

DCNS is also marketing a underwater vehicle version above. It comprises a torpedo like capsule containing just one medium-range (20 km) Mica missile that is torpedo tube launchable at any depth. The capsule is similar to the type developed for submarine launched Exocet anti-ship missiles.
A test rig (above) for an IDAS system launch canister intented to be mounted in a torpedo tube. The system may carry 4 to 8 missiles per torpedo tube. (Courtesy defense govr fr). See possible targets of IDAS below.

Germany's TKMS has been developing the Interactive Defence and Attack System for Submarines (IDAS) SLAM system for Type 212 subs. It is described as 4 missiles housed in a launch canister in the torpedo tube using a IR seeker, fiber-optic data link between the control console and a single-stage, rocket motor providing a range of 20km. The operator on board the submarine may alter the course of the mission at any time. In addition, reconnaissance results and target images obtained by means of the seeker can be evaluated in the submarine. 

It remains a point of contention whether IDAS has been actually fitted to Germany's latest Type 212 submarines. There is no mention of IDAS on latest commissioned  https://de.wikipedia.org/wiki/U_35_(Bundeswehr) or on not yet commissioned  https://de.wikipedia.org/wiki/U_36_(Bundeswehr) .

My view is that IDAS is still not operational on 212s. An IDAS missile was tested in the Baltic on Type 212A U33 in May 2008 and did hit a simulated air target. The IDAS consortium indicates it is  conducting the Initial Development Program aiming at verification of the system with firings from a submerged submarine against real targets - see http://www.diehl.com/en/diehl-defence/products/guided-missiles/idas.html .

Alternatively, the IDAS could, in theory, be fired from the Gabler Maschinenbau TRIPLE-M mast system. However the TRIPLE-M mainly features the "Muraena" RMK 30mm recoiless "autocannon" as the preferred solution for nosey helicopters or MPAs. The Muraena can also be used against small pirate boats (eg. trawler sized) that are not worth a torpedo.

These French and German concepts can only be fully assessed and compared when they are mature, tested and operational technologies.

Meanwhile Russia may have developed a more mature SLAM system. Kilo submarines as well as Akula or Yasen SSNs can be fitted with launchers for missiles from the broad Igla family (perhaps  "Strelets Igla-S" SA-N-24) missiles. They come in 1 to 3 shot containers for sail-surface firing. There are also 8 shot containers that may be torpedo tube mounted. Their range may be up to 6km. 

The US, with its all nuclear sub force and only nuclear sub production, may value maintaining submarine stealth more highly - to the exclusion of developing SLAM systems.



Anonymous said...

Hi Pete

I do not think that submarine can aim its sights on the plane which flies at high speed. Conventional submarine is extremely powerless, it can move only for quite short period at maximum speed (max. 1 hour at 20knot/h). Enemy can easily estimate location of the submarine after SLAM launch, but the submarine cannot escape from enemy’s counterattack. That’s why Soryu submarine loads one or two (or no) Harpoon.


Peter Coates said...

Hi Anonymous

All of the missiles (except for the old, no longer used Blowpipe) have mainly automatic targeting features so - especially for torpedo tube launched missiles - there is no stage that a submarine has to physically see an aircraft or guide it using a periscope.

An example is infra-red seeker for the IRIS-T missile used for the IDAS https://en.wikipedia.org/wiki/IRIS-T#IDAS. These missiles would fly up to Mach 3 so able to handle a marine patrol aircraft and of course a helicopter. May not be able to shoot down an ASROC type missile.

You are right that subs become easier to detect and track when they use SLAMs. SLAM seem more a weapon that is used when a sub is already detected - with perhaps just 5 seconds to use a SLAM before an aircraft's own ASW weapon hits the sub.

Yes Harpoons have huge IR signatures.



MHalblaub said...

Dear Pete,

the IDAS missile was tested on U33 in May 2008 and did hit a simulated air target.

The French first tried a PR-version with a mast mounted MICA but then realized that this was a bad idea. Then DCNS came up with a tube launched version but only one missile will replace one torpedo. The IDAS system can carry at least 4 missiles for one torpedo: http://www.defense.gouv.fr/var/dicod/storage/images/base-de-medias/images/ema/sitta/navdex-2015/stand-tkms_missile-soum-air-idas/5213559-1-fre-FR/stand-tkms_missile-soum-air-idas.jpg
(According to missile size 6 or 8 units per torpedo might be possible. The picture is of a test rig.)

The IDAS system is already implemented in the second batch of German Type 212A submarines and operational since the end of 2014.

The system is also capable to attack land and sea objects. Many sea based anti-air systems may have a problem with a rocket popping up out of nowhere within 2 km of a ship at a slow speed.

The missile is propelled by a rocket engine. So the use would be rather noise and a last action to prevent a helicopter attack. The missile is also a low energy weapon compared to a Harpoon missile (warhead weight 220 kg vs. 11.4 kg IRIS-T).

The rocket engine is built buy a Turkish company. Well, Turkey also buys German submarines...


Peter Coates said...

Hi MHalblaub

Thanks for the information. I have used some of it in the text.

You'll see that I am still searching for proof that IDAS is actually operational on the latest 212s (eg. U35 and U36). According to http://www.naval-technology.com/projects/type_212/ U33 is the platform for a series of flight tests of IDAS - with U33 conducting the 2008 test.



MHalblaub said...

Dear Pete,

I read or even heard it in the news somewhere that the missile system was officially introduced. The news was related to the communications buoy but it was also mentioned that the missile system did work.

On the other side the official distributor Diehl writes: "Currently the IDAS consortium is conducting the Initial Development Program aiming at verification of the system with firings from a submerged submarine against real targets."

There is also an old PDF of 2008 with a small picture on front page of the original missile test.

Norway is also interested in the IDAS missile:
"An Ula-class submarine will conduct Norway's first IDAS test launch in 2015"http://www.janes.com/article/48379/norwegian-submarine-poised-for-idas-test

Another interesting point is this:
"[...],according to an officer from Germany's naval headquarters, who also told IHS Jane's that the German Federal Ministry of Defence (MoD) is expected to decide soon whether to initiate an acquisition programme for an IDAS-like missile system."

That might be the reason why the missile is not officially introduced. The system was not bought by German Navy!

I did not heard about any tests according to the MICA missile.


Peter Coates said...

Hi MHalblaub [at August 1, 2015 at 2:23 AM]

Looks like the whole IDAS issue is "up in the air" - pardon the pun :)

Thanks for http://www.janes.com/article/48379/norwegian-submarine-poised-for-idas-test which also says:

"A German Navy requirement could pitch IDAS against France's A3SM system".

So Germany and France may eventually choose just one system. Pooling development and supply resources for just one NATO-EU system certainly makes sense.

I suppose the increasing threat from Russian MPAs in the Baltic may justify Norway buying SLAMs for Norway's Ulas.



Anonymous said...

Can submarines detect MPA when they are submerged. If yes then generally who first detects the other - the sub or the MPA ?