Submarine Anti-Air Capability

The Navy is looking to develop an anti-air missile for use in submarines (and surface ships).
 

The U.S. Navy has shared details about its vision for a new family of modular surface-to-air missiles that is expected to include a version that will arm future variants of the Virginia class submarine.[1]

The War Zone website has an interesting article about this with a decent discussion of the weapon and some of the benefits and drawbacks.[1]  The weapon is presented as a modular miracle that can include hypersonic versions, various ranges, and various packaging options and will be capable of destroying everything that flies, from drones to hypersonic ballistic missiles.  Truly a miracle weapon … as all new weapons are.
 
Will this be a common sense, evolutionary development or enhancement of an existing, proven weapon?  No!  It will be revolutionary!
 

The United States Navy (USN) is seeking a new, modular interceptor to serve as the basis for the Naval Modular Missile (NMM) program, a next-generation initiative designed to revolutionize surface naval capabilities … [1]

How many weapon systems just over the last few years have promised to revolutionize naval warfare?  Dozens!
 
How many weapon systems have actually revolutionized naval warfare?  None!
 
And yet we keep making the claim.  Hmm …
 
But, let’s get back to the specifics on this particular system.
 
The article describes the potential use by submarines to shoot down ballistic missiles in the launch/boost stage, at any point in flight, or for terminal defense as well as for use in providing AAW protection for carriers and, of course, for shooting down local ASW helos and patrol planes. 
 
To be fair, the article does briefly mention a few potential issues with this and we can think of others.
 
A submarine operating tactically close enough to a surface group to provide anti-air protection is subject to the ages old problem of blue-on-blue friendly fire.  No surface ship is going to allow an unknown submarine to operate near it on the possibility that it might be friendly.  Submarines are a sink-on-sight target, no questions asked.  It is the responsibility of the submarine to not operate near any other friendly submarine or ship because of the inability to distinguish friend from foe.
 
Every subsurface to air missile cuts into the very limited missile inventory of the submarine and reduces its offensive capability which is, of course, the submarine’s entire reason for being.  A submarine’s need for subsurface to air (SSAM) capability would be extremely rare.  Let’s face it, if you’re a submarine captain and you find you need SSAM very often then you’re not doing your job correctly!
 
A submerged missile launch requires the submarine to come to a shallow depth – generally the opposite of what a submarine wants to do in combat.
 
A missile launch creates a great deal of noise, heat, and visual display.  In other words, it likely gives away the submarine’s position.
 
Most obviously, the major issue is targeting.  A submerged submarine has extremely limited air search capabilities so where is the targeting for all these wondrous anti-air scenarios coming from?  Even the local anti-air scenario presents difficulties in targeting.  You may be able to hear a helo and have a general direction but that’s not enough for an anti-air launch.  Surface ships with exact radar pictures have a hard time establishing exact targeting for SAMs and a submerged submarine has far less chance.  Simply launching a SSAM and hoping it can find a target somewhere in the hemisphere around the sub is a recipe for wasting missiles. 
 
As far as receiving targeting from a remote platform, it is challenging, at best, to send real time targeting data to a submerged submarine without unacceptable risk to the submarine.  This also ignores the practical question of what platform could survive long enough to produce targeting data deep inside enemy waters.
 
 
Discussion
 
The SSAM inventory on a submarine would be very small unless someone wanted to abandon the submarine’s primary mission and instead perform AAW.  Is a very small inventory, meaning a very small AAW contribution, worth risking the submarine and compromising its main role?  I think not.  This smacks of yet another example of the Navy’s misguided attempts to make every platform a single-handed war winner.  We have ships designed specifically for the AAW role.  Let them do their job and let submarines do theirs which is offensive operations.  Do we want to risk (due to friendly or unfriendly fire) a several billion dollar sub trying to shoot down a million dollar missile when there are surface ships (Aegis) designed and suited exactly for that task?
 
Some might say that a submarine could be the unseen, forward AAW “shooter” with targeting provided by some other platform in a scenario analogous to the unmanned USV “shooter” vessel being placed far in front of a surface group and cued by a Burke or patrol plane .  Of course, that ignores the problem of how to communicate real time targeting data to a far distant, submerged submarine (as well as the blue-on-blue issue).  As far as I know, that’s a practical impossibility.
 
That said, it might be worthwhile having a half dozen or so SSAMs for the local defense scenario (anti-ASW helo) if the targeting issue can be solved.
 
There’s a reason why there has not been wide spread adoption of this technology among world navies.
 
 
 
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[1]The War Zone website, “U.S. Navy Is Seeking A Submarine Launched Anti-Air Missile”, Joseph Trevithick, 31-Jul-2026,
https://www.twz.com/sea/u-s-navy-is-seeking-a-submarine-launched-anti-air-missile