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Sea-based Anti-Ballastic Missile Intercept System (SABMIS)

Triton

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The Sea-based Anti-Ballastic Missile Intercept System (SABMIS) program, sometimes referred to as Seabourne Anti-Ballistic Missile Intercept System, was a US Navy program to develop a seabourne ICBM defense. Contracts to study the concept were awarded in 1967 to Hughes Aircraft Company, Lockheed Missiles and Spacecraft Company, and Newport News Shipbuilding and Drydock Company working in concert. The SABMIS program studied the use of submarines and surface ships as launch platforms for ABM missiles. With the ability to move these ships forward to positions around the periphery of the Soviet Union or People's Republic of China, it would be possible to detect the launch of enemy missiles and intercept them during the boost or mid-course phase of their flight trajectory.

One of the designs created by the SABMIS program was an anti-ballistic missile ship. From Jane's Fighting Ships 1969-70:

ANTI-BALLISTIC MISSILE SHIP. The Navy also is studying a Sea-based Anti-Ballistic Missile Intercept System (SABMIS). The SABMIS concept is offered by the Navy as a supplement and possibly alternate to the "thin" Safeguard/Nike-X Anti-Ballistic Missile (ABM) system proposed by the Nixon Administration. Although certain factions within the Navy and in the Congress have advocated a comparative analysis of the proposed SABMIS and Safeguard concepts, the official policy of the Departments of Defence and Navy has been to consider SABMIS only as a study for a backup or "in depth" complement to the Safeguard system. Reportedly, approximately $3,000,000 has been spent on SABMIS compared to approximately $4 billion on Safeguard Nike-X studies, research, and development. In view of the existing political situation with President Nixon's Administration firmly committed to a policy of deploying the Safeguard system, it appears unlikely that SABMIS could be developed so long as there is any interest in the Safeguard system. The proposed SABMIS ship is described on a subsequent page of the listings for Strategic Warfare Ships.
Displacement, tons 20000-30000 full load
Length. feet (metres) approx 700 (214.0)
Missiles approx 40-60 ABM
Several Point Defense Missile System (PDMS) launchers
Nuclear reactors 2 pressurised-water cooled
Main engines Geared turbines, 2 shafts

The US Navy has studied the feasibility of a Sea-based Anti-Ballistic Missile Intercept System (SABMIS) to provide an effective and relatively low cost defence against intercontinental ballistic missiles. The SABMIS - concept provides for tracking/missile ships which could be deployed to intercept enemy ICBMs early in their flight, before multiple warheads and penetration decoys break away from the launching rocket. Thus, a sea-based ABM would have one target per enemy ICBM whereas a land-based ABM system in the target area would have to cope with several re-entry packages for every enemy missile which is fired.

The radar to detect an enemy ICBM launching, the fire control computers, missile guidance, and the ABM missile launchers would all be mounted in a single ship under the SABMIS concept. It is anticipated that an extremely small number of ships could provide the capability of intercepting the approximately 40 intercontinental missiles which Communist China would be able to launch against the United States in the mid-1970s. Also, the SABMIS concept could provide a low-cost "thin" defence against an "accidental" Soviet ICBM launching of a small number of missiles against the United States. (Most authorities agree there is today no possiblity of providing defence against an all-out Soviet ICBM strike against the United States). However, even against a threat of this size a force of several SABMIS ships may be desired, to provide for survivability in the event of war and for normal overhaul and training. Still, a multi-ship SABMIS force, with nuclear powered-escort ships, is expected to cost considerably less than the $8 to 40 billion Safeguard, Nike-X "thin" ABM defence now being proposed for the United States.

A sea-based ABM would appear to offer several major advantages over a land-based system:

•The problems of detecting and destroying an ICBM' during the launch-boost stage is far less complicated than seeking to locate and destroy several re-entry packages (warheads and decoys).

• The Safeguard/Nike-X ABM is a "sector system" with each of the planned 12 missile sites defending a sector of the United States. Thus, each site must have the capability of intercepting all intercontinental missiles which China is expected to have available in the mid-1970s. However, a single SABMIS ship could be positioned to intercept virtually all missiles being fired at the United States because of the limited China-to-United States ICBM trajectory spectrum.

• A sea-based system would not increase the number of strategic targets within the United States which would be attacked in a nuclear conflict.

•The mobility of a sea-based ABM will enable the defence to be shifted as the threat changes. For example, an ABM system in the United States could not provide for defence against ICBMs aimed at Japan. A sea-based ABM could counter Chinese ICBMs being launched against virtually any Asian target.

•Should the opposition develop an anti-ABM system (in the same manner that anti-radar missiles have been developed) the sea-based ABM ships probably would be less vulnerable than the land-based ABM and enemy "misses" would not devastate the continental United States.

• Shipboard systems appear to have a longer life than do fixed weapon complexes on land, a result of the feasibility of adopting a given ship hull to changing missions and equipment.
Artist's conception of SABMIS anti-ballastic missile ship.
 

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sferrin

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Wonder what kind of missiles they had in mind.
 

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Was my question, too and enhancing the drawing only brought flying phalli....
Wouldn't be a naval adaption of the LIM-49A Spartan a logical choice, especially with regards
to the drawing of the ship ? Fixed array antennas and VLS as a shipboard equuivalent of
landbased silos ?
 

sferrin

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Jemiba said:
Was my question, too and enhancing the drawing only brought flying phalli....
Wouldn't be a naval adaption of the LIM-49A Spartan a logical choice, especially with regards
to the drawing of the ship ? Fixed array antennas and VLS as a shipboard equuivalent of
landbased silos ?
Launch would be "interesting" as those weren't cold-launched and had half-million lb thrust motors.
 

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Flight had the rather odd note in October 1971 that SABMIS would use "Spartan or Polaris
missiles to intercept incoming missiles before warhead dispersal takes place." Spartan makes sense, Polaris is downright odd.

Another reference (History of Strategic and Ballistic Missile Defense: Volume II: 1956-1972) refers to "elements simialr to those of the Nike X system", which might imply reuse or adaptation of Spartan or just development of a similar missile and associated radars.
 

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sferrin said:
Launch would be "interesting" as those weren't cold-launched and had half-million lb thrust motors.
The Navy's whole surface ship VLS effort was based on hot launch, so the US didn't regard this as an insurmountable problem. SABMIS was admittedly much larger and hotter than Mk 41 (for example), but probably didn't have to concern itself with reusing the launchers without extensive reconstruction, so a fairly direct adaptation of the land-based silo arrangement seems perfectly plausible.
 

sferrin

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TomS said:
sferrin said:
Launch would be "interesting" as those weren't cold-launched and had half-million lb thrust motors.
The Navy's whole surface ship VLS effort was based on hot launch, so the US didn't regard this as an insurmountable problem. SABMIS was admittedly much larger and hotter than Mk 41 (for example), but probably didn't have to concern itself with reusing the launchers without extensive reconstruction, so a fairly direct adaptation of the land-based silo arrangement seems perfectly plausible.
That's a pretty tall missile for VLS ship launch. (55 feet) Then the space for the exhaust plenum etc.
 

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Well, the SABMIS ships were going to be rather large (20-30,000 tons), so I don't see the sheer size of Safeguard as an absolute impediment. That said, given the era, I do think it's likely that a new missile would be developed, rather than taking Safeguard on directly. The difference between Safeguard's late mid-course/terminal intercept and SAMBIS's late boost-phase/early midcourse intercept would seem to have a significant impact on the missile design.

Even a new missile would be big and energetic, but the Navy didn't seem to mind that, necessarily. If it was a problem, well, there was plenty of expertise with hot-gas generators for Polaris, which would still work in surface ship applications.

The sketch shown above is probably only a rough estimate. The midships VLS are about 35-40 feet deep but there's another undefined machinery compartment below them, so who knows what they had in mind (exhaust plenum, generators, etc)?
 

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Such a cool concept should be revived with a converted helicopter carrier and carry anti-air, anti-missile and land attack missiles. You might even have enough room for a couple of self defense lasers.
 

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Spartan would be hopeless performance wise for the intended role, even using the much lightened Spartan II with a lower yield warhead its just too slow. It is far more likely that the desired missile was notional, like the entire ship. The fact that the ship does not have two radar systems, nor MSR like antennas suggests that it wouldn't even be using Safeguard fire control.
 

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I wonder if there wasn't some subtle misdirection in play, and SABMIS was actually intended to be equipped with a naval version of what became the Sprint missile?
 

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What on earth sense would it make to arm the ship with a weapon with such limited range?
 

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I can't see Sprint being used (range to short). Spartan is more likely, but I don't think it would have the legs as it only had 450 - 500mile range.

Based on that short description from Jane's its main target is Chinese ICBMs and it is intended to kill the ICBM during the boost phase. So, SABMIS would be cruising around in the Sea of Japan or the Sea of Okhotsk. From there, it would be a fairly long intercept for Chinese launched ICBMs heading for the USA (and possibly over Soviet territory as well). A very rough guess would be in the 1000 to 1800 mile range to try and intercept during the boost phase. So we need a missile that has two to three times the range of Spartan.

The article mentions that detecting and intercepting a launch is easier than intercepting the RV and/or decoys, and at a basic level that is correct. The ICBM is a single vehicle, with a large IR signature and is traveling at a relatively slow speed during the boost phase. However, the SABMIS is 1500 miles away. Unless it had a OTHR, it would not be able to detect a launch autonomously. Launch detection would be dependent upon the (USAF) MiDAS or from 1970 the (USAF) DSP. It would only be once the ICBM is above the horizon relative to the SABMIS that it could detect it. Then SABMIS would launch the missile for intercept.

I think somewhere, it was mentioned that the Polaris or Poseidon SLBM would be used as the basis for the SABMIS missile. This would make sense as the tubes and other launch control systems already existed within the Navy. Just change the guidance and warhead and away you go. However, the performance of these SLBM as an anti-ICBM I don't think would be there to ensure a quick intercept before the launched ICBM starts dispensing its RV (assuming its a MRV/MIRV) and decoys.

So using some of the Nike X/Spartan technology would make sense - but its an Army system, so there would be resistance from the Navy. In addition, how much of the radars etc would be able to be translated to a moving platform I am not sure. Very different enviromentals.

The more I look into it, the more I think SAMBIS was not a practical system at the time. It was possibly a last grasp at the ABM role by the Navy, but a half hearted attempt.
 

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The reason why I suggested a version of Sprint was the fact that it was originally intended to be primarily used against SLBMs of the period, which had a shallower trajectory than ICBMs.
 

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Grey Havoc said:
The reason why I suggested a version of Sprint was the fact that it was originally intended to be primarily used against SLBMs of the period, which had a shallower trajectory than ICBMs.
Sprint is only useful as a point-defender. If someone were to lob a ballistic missile at the ship, Sprint would come in handy, but otherwise it'd have virtually no chance to be useful. Even a depressed-trajectory SLBM would fly far too far overhead, unless the SABMIS ship was right on top of the launching sub. Ceiling for Sprint was about 100,000 feet.

Now, put a stage under sprint, maybe. But that's just makin' stuff up.
 

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Orionblamblam said:
Grey Havoc said:
The reason why I suggested a version of Sprint was the fact that it was originally intended to be primarily used against SLBMs of the period, which had a shallower trajectory than ICBMs.
Sprint is only useful as a point-defender. If someone were to lob a ballistic missile at the ship, Sprint would come in handy, but otherwise it'd have virtually no chance to be useful. Even a depressed-trajectory SLBM would fly far too far overhead, unless the SABMIS ship was right on top of the launching sub. Ceiling for Sprint was about 100,000 feet.

Now, put a stage under sprint, maybe. But that's just makin' stuff up.

*ahem*



:eek:
 

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Orionblamblam said:
Sprint is only useful as a point-defender.
That was the point that I rather badly made. Spartan and Sprint were intended to defend the target thus the missile was launched from your home territory. SABMIS was intended to intercept the missiles on launch, so you have to have quite a long range missile as you have to reach into enemy territory rather than launching from the territory that you are defending.

As for that artwork, that is an interesting upper stage (UPSTAGE?) put on a Sprint with probably the 1st stage of Spartan. Interesting concept.....
 

sferrin

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hark40 said:
Orionblamblam said:
Sprint is only useful as a point-defender.
That was the point that I rather badly made. Spartan and Sprint were intended to defend the target thus the missile was launched from your home territory. SABMIS was intended to intercept the missiles on launch, so you have to have quite a long range missile as you have to reach into enemy territory rather than launching from the territory that you are defending.

As for that artwork, that is an interesting upper stage (UPSTAGE?) put on a Sprint with probably the 1st stage of Spartan. Interesting concept.....
HEDI/Kite
 

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hark40 said:
I think somewhere, it was mentioned that the Polaris or Poseidon SLBM would be used as the basis for the SABMIS missile.

I've never heard that, and while its not impossible the burnout velocity of Polaris systems is still unlikely to be high enough to be effective even with a much lighter warhead. Poseidon, maybe.



However, the performance of these SLBM as an anti-ICBM I don't think would be there to ensure a quick intercept before the launched ICBM starts dispensing its RV (assuming its a MRV/MIRV) and decoys.

That issue is not not a very big problem in this context, even if RVs are released very early in flight, which is unlikely for accuracy reasons, drag rules out early release of most decoys, they'll remain in a fairly dense cloud until well after the apogee which means a single nuclear interceptor can still kill them all. This was a major part of the reason why the Spartan missile had a 5 megaton warhead itself.

The more I look into it, the more I think SAMBIS was not a practical system at the time. It was possibly a last grasp at the ABM role by the Navy, but a half hearted attempt.

I'm not sure it was practical either, but I really see no reason to assume it would not have used a custom missile. An interceptor with a megaton class nuclear warhead and burnout velocity comparable to the velocity of the threat ICBM would be effective. Its just might have to be the size of a Minuteman to do this with the technology of the time, Poseidon might work but I kind of doubt it given the need for a very large warhead to blowup a threat cloud. That ship looks more then big enough to hold several dozen Minuteman in any event. The real problem I think would be making the required high power phased array radar and computer systems work on a moving ship before the 1980s. That part is almost certain to be impossible.
 

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Just a note:
I've started to make a line-drawing based on the pictures posted earlier, as well as a possible modernization with 3 or 5inch naval guns and Phalanx CIWS
Except in quality similar to my 2nd Modernization plan Iowa
 

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Here is my view of the design based mostly on the first drawing of artist impression:

 

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Great work ! It's fitted with Sea Sparrow, I suppose. What are those other launchers ?
 

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Jemiba said:
Great work ! It's fitted with Sea Sparrow, I suppose. What are those other launchers ?
4 Sea Sparrow launchers yes. But what other launchers?
 

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Sorry, the objects besides the deckhouses probably are directors for Seasparrow ?
 

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Yep, those are the Mk 95 radars for the Mk 91 GMFCS.

My only quibble with the drawing is that the artist's impression we have of the design only shows one Mk 95 per quarter, not two. But adding a second channel on each quarter certainly makes good sense considering the high cost/value of the ship.
 

Tzoli

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Jemiba said:
Sorry, the objects besides the deckhouses probably are directors for Seasparrow ?
Those are the Mk 95 "Bug Eye" Illuminators:
 

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TomS said:
Yep, those are the Mk 95 radars for the Mk 91 GMFCS.

My only quibble with the drawing is that the artist's impression we have of the design only shows one Mk 95 per quarter, not two. But adding a second channel on each quarter certainly makes good sense considering the high cost/value of the ship.
I've thought these always installed in pairs! Well at least all the ships I've seen with these illumination radars have 2 pairs not one, for a single launcher.
 

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Smaller ships got single installations. Check out the Oslo and Lupo class frigates, for example.
 

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Hi,


By change I'm working on a 3D model of SABMIS and was wondering what the opinion of the board was on the differences between the profile view and the artists impression - I've been using the former, with some of the stylistic aspects of the latter that Tzoli has captured so well.


RP1
 

Tzoli

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I think the first artist impression is the real one, but it is too clean to me. It lacks the little details a ship would have of this size.
Such things as the smaller radars, antennas, hull objects, walkways/catwalks etc. I also found lack of any Helicopter Hanger so I've added that as well.On another forum they said the the other drawing with the Japanese text is not accurate, both in the superstructure placements as well as the funnel, as US ships were purely nuclear and not CONAS like the Soviet Kirov and other warship designs of Russia at that time.
 

TomS

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I wouldn't actually expect a hangar on a high-value ship of this era. Even ships that you'd expect to have helicopters, like the amphibious command ships, didn't have them in this era. If they were hosting a helicopter for a short whioe, they'd just park it on deck.

I would expect them to have shoehorned in a couple of twin 3-inch/50 mounts though. They were pretty much universal for ships without other gun armament in the late 60s/early 70s. In due course, they would have been replaced with CIWS, of course.
 

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You are wrong.
There were hangers on ships in 1970's era:
Virginia class CGN (Below-Deck Hanger)
Belknap class CG (Enclosed hanger)
Kidd class DDG (Enclosed hanger)
Spruance class DDG (Enclosed hanger)
Oliver Hazard Perry class FFG (Enclosed hanger)
Knox class FFG (Enclosed hanger)
Garcia class FF (Enclosed hanger)
 

RP1

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high-value ship of this era

The growth of naval helicopters into "something generally useful" had not yet occurred and they were still associated with a specific weapon or capability.


I would note that the profile has a below deck hangar as per the CGNs, though, whereas the artists impression seems to have none. FWIW I suspect that they may both be genuine, but developed at different times or for different purposes. The profile is just too worked out to be made up, IMHO.


RP1
 

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Tzioli, as RP1 noted, these helos were almsot entirely associated with specific weaopn systesm (LAMPS and ASW). Ships without specific ASW taskings (and the sonar fits that went with them) generally didn't have helos.
 

Tzoli

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I've did not said fake just not accurate.
Look at it:

It shows a VLS system in the nose, probably too forward but which the text says nothing and Anti Air weaponry only adopted to VLS cells much later.
I see an enclosed Hanger not a below deck telescopic one (hence the large empty area under the aft superstructure but above the main deck)
Also the large funnel from the engineering room meaining some sort of Steam Turbine (only boilers need funnel, turbines don't) and the rudders are also connected to these rooms. Not to mention the different arrangements of structures on this drawing and on the artist's expression.
 

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Whoops - my mistake, the hangar is in the aft superstructure. The things forward are not a VLS - they are the anchor chain pipes with the chain lockers shown under them.


I'm not sure that the presence of a funnel means anything specific for the machinery - both versions have one (there is a small one of the artists impression) and it looks to be very small so could be for auxiliary diesels. The superstructure differences could just reflect different versions of the design - for example, I suspect that the profile view has the radars in a Ticonderoga-style arrangement rather than at 45 degrees.


RP1
 
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