Register here

Author Topic: Sea-based Anti-Ballastic Missile Intercept System (SABMIS)  (Read 23637 times)

Offline Triton

  • Senior Member
  • CLEARANCE: Top Secret
  • **
  • Posts: 9704
  • Donald McKelvy
    • Deep Blue to Wild Blue
Sea-based Anti-Ballastic Missile Intercept System (SABMIS)
« on: November 14, 2009, 01:30:04 pm »
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:

Quote
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.


Quote
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.
« Last Edit: November 14, 2009, 02:08:45 pm by Triton »

Offline Triton

  • Senior Member
  • CLEARANCE: Top Secret
  • **
  • Posts: 9704
  • Donald McKelvy
    • Deep Blue to Wild Blue
Re: Sea-based Anti-Ballastic Missile Intercept System (SABMIS)
« Reply #1 on: November 14, 2009, 02:04:42 pm »
Inboard profile and dorsal view of SABMIS anti-ballastic missile ship.
« Last Edit: November 14, 2009, 02:32:33 pm by Triton »

Offline Triton

  • Senior Member
  • CLEARANCE: Top Secret
  • **
  • Posts: 9704
  • Donald McKelvy
    • Deep Blue to Wild Blue
Re: Sea-based Anti-Ballastic Missile Intercept System (SABMIS)
« Reply #2 on: November 14, 2009, 05:03:08 pm »
In a "Draft Memorandum From Secretary of Defense Clifford to President Johnson" dated July 28, 1968, Secretary of Defense Clark Clifford recommended that the President reject the Joint Chiefs of Staff recommendation for Contract Definition on a ballastic missile ship in FY 1970. The research and development and operating costs of eight ships over ten years was estimated at $5.9 billion.
http://webdoc.sub.gwdg.de/ebook/p/2005/dep_of_state/www.state.gov/r/pa/ho/frus/johnsonlb/x/9101.htm
« Last Edit: November 17, 2009, 09:59:52 am by Triton »

Offline sferrin

  • Senior Member
  • CLEARANCE: Top Secret
  • **
  • Posts: 11251
Re: Sea-based Anti-Ballastic Missile Intercept System (SABMIS)
« Reply #3 on: March 27, 2013, 07:10:23 pm »
Wonder what kind of missiles they had in mind.
"DARPA Hard"  It ain't what it use to be.

Offline Jemiba

  • Global Moderator
  • CLEARANCE: Top Secret
  • ****
  • Posts: 7936
Re: Sea-based Anti-Ballastic Missile Intercept System (SABMIS)
« Reply #4 on: March 27, 2013, 10:32:11 pm »
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 ?
It takes a long time, before all mistakes are made ...

Offline sferrin

  • Senior Member
  • CLEARANCE: Top Secret
  • **
  • Posts: 11251
Re: Sea-based Anti-Ballastic Missile Intercept System (SABMIS)
« Reply #5 on: March 28, 2013, 05:31:13 am »
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. 
"DARPA Hard"  It ain't what it use to be.

Offline TomS

  • Senior Member
  • CLEARANCE: Top Secret
  • **
  • Posts: 2935
Re: Sea-based Anti-Ballastic Missile Intercept System (SABMIS)
« Reply #6 on: March 28, 2013, 05:35:56 am »
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. 

Offline TomS

  • Senior Member
  • CLEARANCE: Top Secret
  • **
  • Posts: 2935
Re: Sea-based Anti-Ballastic Missile Intercept System (SABMIS)
« Reply #7 on: March 28, 2013, 05:43:04 am »
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.

Offline sferrin

  • Senior Member
  • CLEARANCE: Top Secret
  • **
  • Posts: 11251
Re: Sea-based Anti-Ballastic Missile Intercept System (SABMIS)
« Reply #8 on: March 28, 2013, 06:21:40 am »
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. 
« Last Edit: March 28, 2013, 06:24:32 am by sferrin »
"DARPA Hard"  It ain't what it use to be.

Offline TomS

  • Senior Member
  • CLEARANCE: Top Secret
  • **
  • Posts: 2935
Re: Sea-based Anti-Ballastic Missile Intercept System (SABMIS)
« Reply #9 on: March 28, 2013, 07:27:30 am »
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)? 



Offline bobbymike

  • CLEARANCE: Top Secret
  • ***
  • Posts: 8522
Re: Sea-based Anti-Ballastic Missile Intercept System (SABMIS)
« Reply #10 on: March 28, 2013, 09:25:14 am »
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.
Books are the quietest and most constant of friends; they are the most accessible and wisest of counselors, and the most patient of teachers.

Charles W. Eliot

Offline eshelon

  • CLEARANCE: Confidential
  • *
  • Posts: 68
  • unconventional solutions
    • Fire-At-Will
Re: Sea-based Anti-Ballastic Missile Intercept System (SABMIS)
« Reply #11 on: March 28, 2013, 01:33:46 pm »
Today's approach is Ballistic Missile Defence variant of LPD Flight II (modified LPD 17/San Antonio Class).

Offline Sea Skimmer

  • CLEARANCE: Secret
  • **
  • Posts: 394
Re: Sea-based Anti-Ballastic Missile Intercept System (SABMIS)
« Reply #12 on: March 28, 2013, 03:48:40 pm »
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.

Offline Grey Havoc

  • Senior Member
  • CLEARANCE: Top Secret
  • **
  • Posts: 8107
  • The path not taken.
Re: Sea-based Anti-Ballastic Missile Intercept System (SABMIS)
« Reply #13 on: March 30, 2013, 02:20:51 am »
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?
The sole imperative of a government, once instituted, is to survive.

Offline Sea Skimmer

  • CLEARANCE: Secret
  • **
  • Posts: 394
Re: Sea-based Anti-Ballastic Missile Intercept System (SABMIS)
« Reply #14 on: March 30, 2013, 04:57:18 am »
What on earth sense would it make to arm the ship with a weapon with such limited range?