THE NUCLEAR WEAPONS OF THE UNITED STATES NAVY

1945 – 2013

Don G. BoyerHaleiwa, Hawaii

March 2013

SECTION PAGE

Part 1: The Early Days 2

Part 2: The Beginning of the Navy's Nuclear Weapons Program 7

Part 3: The First "New" Bomb 12

Part 4: More Bombs 15

Part 5: The Beginning of the Megaton Era 17

Part 6: Still More Bombs 20

Part 7: Anti-Submarine Warfare Weapons 27

Part 8: Rockets and Missiles 32

Part 9: Ballistic Missiles 39

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THE NUCLEAR WEAPONS OF THE UNITED STATES NAVY 1945 – 2012

Part 1: The Early Days

This article is a general history with some operational details on all the nuclear weapons that have appeared in the inventories and aboard the ships of the US Navy since the end of WWII. While there is much material on shipboard weapons from the days of sail to yesterday, little is covered concerning the feared (and often overlooked) arena of the nuclear arsenal that came to be after 1945. The fact that not much is known about the nuclear weapons program because of deep security classifications doesn't help matters either. (Attached to this article is a table for a quick reference on the entire nuclear arsenal of the United States for those who may be interested. I make no claims that it is all-inclusive and comprehensive. For those with an interest in how the navy trained itself up for the nuclear weapons role, there are some good articles on the subject on the Navy Nuclear Weapons Association website. For weapons in general, the prime source is Chuck Hansen's “Swords of Armageddon” publication available on a very expensive CD.)

Since the incredible shock delivered to the world in the skies over Hiroshima and Nagasaki, no weapon has been so historically significant, reviled, and generally the subject of so much hysteria and myth over the potential fate of mankind than have nuclear weapons, and this includes chemical and biological threats that have the potential to create similar death tolls. The looming presence of potential total nuclear destruction has colored the politics of the late

20th

century to an incalculable degree and has significantly altered history even with the weapons never having actually been used again. The potential of nuclear weapons by the thousands deployed or locked away in secret bunkers around the world thousands of miles from any actual conflict has touched all our lives in many ways.

Before July of 1945, only the Good Lord had held the keys to the potential destruction of mankind. While saying a lot about God's obvious forbearance, not much thought was given to the possibility of something like that actually happening, except by the extreme religious zealots who pointed (futilely) at every portent such as rock and roll and short skirts as the preamble to human dissolution. With the early morning flash of light in the New Mexico desert in July of 1945, suddenly the Good Lord, in what some would consider a Promethean gesture of considerable humor and insight, handed one of the keys to humanity, possibility with a view to seeing how well mankind handled such power, considering the endless propensity of humans for declaring their intent to reach god-like levels of benign and enlightened consciousness toward their fellow man on the one hand, while on the other hand continuously slaughtering each other by the tens of thousands on the flimsiest of pretexts, and for thousands of years to boot. Sort of like the adage of putting your money where your mouth is. Some wake-up call, what?

This article sticks strictly to published source material now in the public domain.

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This first section discusses the four initial weapons available to the military following the end of the Second World War and is less about the Navy than it is about the Air Force and the weapons themselves, but that's just the way the history of these weapons unfolded. The Navy will enter, stage left, in the next section.

While the initial delivery capability for nuclear weapons rested entirely with the U.S. Army Air Forces (to become the U.S. Air Force in 1947) from the end of WWII to the early 1950s, early weapons were capable of delivery by two naval aircraft, neither of which were ideal for the situation – The P2V Neptune and the slightly later AJ Savage, of which only the latter (with great difficulty) could be accommodated on the Midway and Essex class aircraft carriers. Both these aircraft were twin engine propeller aircraft (the AJ also had a small turbojet for burst speed) and neither was particularly suitable to the role, particularly (in my opinion) in the area of being able to survive the delivery of a weapon, but that would quickly change as the Navy gained a larger role as part of America's nuclear deterrence capability, against the constant initial resistance of the U.S. Air Force. Navy experiments with the P2 and AJ and weapons casings were conducted in the early 1950s, but no weapons deployed from naval carriers at this time.

The United States' (and potentially the US Navy's, should the ultimate emergency arise) first deliverable atomic weapons were the two initial derivatives of the Fat Man (Model 1561) weapon used on Nagasaki on August 6, 1945. The Model 1561 was the deliverable weapon version of the implosion "Gadget" first tested at the Trinity site in New Mexico in July of 1945. The bomb was 10' 8" long, 5' in diameter and weighed 10,300 lbs. Based on the Nagasaki blast, the yield was officially calculated at 23 kilotons (kt – equivalent to 23,000 tons of TNT). This first implosion weapon utilized about 13.5 lbs of plutonium surrounded by a complex array of layered high explosive "lenses" that burned at different speeds in order to create a spherical implosion shock wave that would compress the plutonium into a critical mass. The implosion would also crush a small polonium/beryllium initiator, creating the flux of neutrons necessary to begin the chain reaction. About 5000 lbs of the weapon was devoted to the high explosives and the extremely complex wiring harness and detonators needed to create an even implosion shock wave. The detonators and wiring harness were specifically designed as a safety factor against accidental detonation. The high explosives package more than anything else was what made the Fat Man "fat."

(To backtrack a little, a word or two on the other bomb of the first nuclear weapons era, the "Little Boy." The Little Boy was a gun-type nuclear device weighing in at 9,700 lbs. and measuring 10' long by 2' 4" in diameter. The gun principle was a very simple and straightforward way of creating a nuclear detonation (by comparison to implosion): a section of fissile material was fired from one end of a tube (thus "gun") into another section of fissile material at a speed sufficient to create a critical mass and also crush an initiator. Smaller than the Fat Man, it also had a smaller yield, the Hiroshima detonation being calculated at 13 – 15 kt. Little Boy used almost ten times as much fissile material (approximately 141 lbs. of enriched uranium) for less yield than the Fat Man and was thus considered from a pure physics standpoint highly inefficient as a bomb compared to the implosion device. As a result, although

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some five weapons assemblies were made of this type of weapon, it was never put into production or stockpiled; it would be the Fat Man derivatives that led the way to the enormous nuclear arsenal eventually produced by the United States (some 72 deployed weapon types and around 64,000 weapons – see the attached table. Note that the Little Boy was never officially designated “MK 1”, the term was applied retroactively when the military began numbering weapons.)

About nine "Fat Man" type weapons (designated MK 2) were hand-manufactured at Los Alamos, two of which were expended in the 1946 Bikini Atoll tests, but the design was almost immediately replaced by its two production derivatives, the Mk 3 and Mk 4. At first, these two weapons were only deliverable by the Air Force's B-29 Superfortress and its upgraded sister, the B-50. (Weapons were not then under the direct control of the military, however; the newly created civilian Atomic Energy Commission had all the early weapons under their control.) Since the Air Force had the only delivery capability, they used this fact to the nth degree in the bitter and divisive internecine post-war squabbling between the American armed services over primacy and budgets, with the Air Force politically maneuvering to control nuclear weapons strategic delivery systems, existing and potential (realizing, of course, that this was impractical – it was all part of the post war re-adjustment of the American military to the realities of the post-war political necessity of having to face off against communism). This squabble resulted in the infamous B-36/super-carrier tiff between the navy and air force that saw the funding committed to the B-36 very long range bomber and the first super-carrier design (the abortive USS United States) cancelled by President Truman. It also led to the creation of the Department of Defense and the separate United States Air Force. The new Department of Defense and the political leadership were quick to recognize that the exclusive use of nuclear weapons by the Air Force was unrealistic, strategically or tactically, and soon developed programs for the development of weapons suited to the roles of the Army, Air Force, Navy and Marine Corps, a policy that paid huge dividends in the Cold War and also resulted in trillions of dollars spent on a multiplicity of weapons systems, many of them fairly short-lived, as scientific progress rapidly advanced during

the latter half of the 20th

century. Whether the expense was worth the results is still under hot debate today. Fortunately, world leaders have to date shown no real propensity for suicide by employing any of these weapons in combat since 1945 when they were most justifiably used to convince the most obdurately stupid military junta known to man to quit the war they had started despite the resulting loss of face that would accrue – a loss of face they considered of more consequence than the destruction of their entire nation and its people.

The first of the Fat Man-derived weapons was the almost identical Mk 3 bomb. One of the major differences was a re-designed tail assembly on the bomb, which was apparently prone to failure. The Bikini Atoll test Able bomb in 1946, dropped from the B-29 Dave's Dream, missed the target ship (the former USS Nevada) by 2,130 feet – a significant error with such a low-yield weapon. This was officially blamed on tail fin failure, although Colonel Paul Tibbets (still with

the 509th

Bomb Group) and his crew made statements to the effect that the crew of Dave's Dream were at least partially responsible for the wide miss due to miscalculating the drop mathematics and navigation parameters, which Tibbets' staff had double-checked themselves

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and disagreed with, but were ignored. Regardless, the Mk 3 was an improvement on the Model 1561 in several areas, including improved fusing and other internal features. The major difficulties with these early weapons were related to the time and manpower it took to get one assembled and ready to go (ten hours and up to 19 personnel) and the "shelf-life" of the weapon once assembled. The early type of batteries used in the weapons (necessary to provide the electrical firing of the weapons HE detonators) could only last nine days, and had to be recharged twice during that period, requiring partial disassembly of the weapon to replace old batteries with fresh, and thus "downing" the weapon for a period. Additionally, alpha particle decay of the plutonium core would eventually damage bomb components due to radiated heat, so the fully assembled bomb could not remain so for extended periods.

The Mk 3 bomb was in the inventory until about 1950, and about 120 weapons were manufactured in three "Mods" (modifications) 0, 1 and 2. Its successor was the Mk 4 bomb, the first nuclear weapon to be built on the "assembly line" principle and the first to be stockpiled in significant numbers. With the deployment of the Mk 4 beginning in 1949, the Air Force began operating its first truly functional and readily available nuclear bomb. In addition to having the improvements of the Mk 3, the Mk 4 benefited from an improved aerodynamic shape and more efficient and compact fusing. The Mk 4 also had the first composite core using both uranium and plutonium, increasing fissile efficiency and additionally had a variety of cores available that would change the yield of the weapon (uranium, plutonium and composite). The Mk 4 also utilized the first really secure safety device on these weapons in the form of "in-flight insertion" (IFI). This kept the nuclear core of the weapon separate from the weapon and its explosives until the bomb was in flight and ready to deliver. Inserting the core into the weapon was not a simple procedure, requiring opening the weapon up, removing some of the explosive lenses, inserting the core and closing the weapon back up and then testing the weapon to ensure all was correctly done and electrically viable. The reverse procedure could be used prior to landing if the weapon was returned. Ground preparation time for the weapon was still lengthy at about 8 hours for assembly and 2 for testing before the weapon was loaded on an aircraft.

The Mk 4 was of the same basic dimensions as its predecessors as it was based on the Mk 3 Mod 1, but was some 500 lbs heavier at 10,800 lbs. due to the differing cores and the IFI assemblies. The most significant feature of the weapon was the variable yield at 1, 3.5, 8, 14, 21 and 31 kt, the latter yield due to the composite core with its more efficient nuclear burning. Operational tests of the Mk 4 core were conducted at Eniwetok Atoll in April and May of 1948 (Operation Sandstone) and the first weapons themselves were in the AEC inventory by late 1948. A total of about 550 MK 4s were produced between 1948 and its withdrawal from service in 1953.

The Mk 4 was the first nuclear weapon deployed outside the United States when nine Mk 4 assemblies were forward deployed to Guam, presumably along with their nuclear cores, during the Korean War. The plan was to deploy ten, but the tenth weapon was lost when the B-29 carrying the weapon crashed at Fairfield-Suisan Air Force Base outside San Francisco on 5 August 1950. The plane suffered an engine failure during takeoff, a second engine failure while attempting to return to the runway and an electrical failure as well. The plane's pilot, Captain

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Eugene Steffes through a magnificent effort got the plane on the ground in a more or less controlled crash and the plane broke apart and burned. Captain Steffes escaped the forward

section of the aircraft and survived; Brigadier General Robert F. Travis, commander of the 5th

Strategic Reconnaissance and 9th

Bombardment Wings was badly injured in the crash; he was removed from the cockpit area but died en route to the hospital. Eighteen other men, both crew and rescue personnel, were killed when the Mk 4's high explosives detonated in the fire. Fairfield-Suisan was renamed Travis Air Force base later that same year.

Four other Mk3/4 incidents involving the loss of the weapon occurred, all in 1950, resulting in much practice and training on the part of the Air Force in handling and flying with nuclear weapons, since much bad PR within the military had occurred. None of the incidents resulted in any radiation hazards to personnel or the public although the weapons were lost or destroyed. With the retirement of the last Mk 4 in 1953, the legacy of the Fat Man ended and newer, smaller, more efficient weapons began to enter the inventory. It was at this point that the US Navy was able to really begin developing its role in nuclear deterrence.

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Part 2: The Beginning of the Navy's Nuclear Weapons Program

When the Second World War ended in September of 1945, the United States navy was the largest and most powerful sea-going fighting force in human history, a force that – caught unprepared at Pearl Harbor – had stopped cold a tenacious and vicious enemy's plans for imperial expansion within a year, mostly with the equipment they had on hand at the time, and then had built itself up to the point where it could successfully fight a two-ocean war against two evil empires and, with the support of the US Army and especially the Marine Corps, wrest any piece of turf away from the enemy without fail. In the case of the actions in the Pacific, the US fleet had almost destroyed the enemy's entire fighting and merchant navy in the process. (Had it not been for the two atomic bombs stopping the process, it would not have been “almost” as far as the fighting fleet would have been concerned.) The navy learned the lessons of sea battle, amphibious assault, air attack and at-sea logistics and applied them as no fighting force ever had before. At the dawn of the nuclear age, the US Navy reigned supreme at sea all over the world.

But once the surrender documents and peace treaties had been signed and the warriors and ships returned home, the navy faced huge problems concerning its future, and not just the reductions in force and personnel faced by all the services. Probably the most worrisome as far as the future of the navy was concerned was nuclear weapons. The navy had no capacity to handle them or deliver them yet, no policy as to their integration into naval matters and no real idea as to their potential future roles in naval matters. Hand in hand with nuclear weapons was the advent of jet aircraft. Compounding these two problems were the ones related to post-war military politics alluded to earlier, with the brash and aggressive Army Air Force's push for independence and their lock on the use of nuclear weapons, which at that time existed only in the form of large, heavy and complex bombs that could only be delivered by the B-29 and the newer B-50 just entering service. Without a nuclear role, the navy could find itself taking a back seat in military affairs, something it was in no way willing to do.

The messy in-fighting over control and use of nuclear weapons is well documented and doesn't need much coverage here. Despite the bitterness of the political in-fighting, resulting in B-36s but no new “super-carrier” for the navy (which could have easily handled both jets and nuclear weapons, having been designed from the start for just that), and despite “the revolt of the admirals” which resulted in several charred careers and resignations, in the end it was obvious that all America's military forces would be involved in the development and use of nuclear weapons carried by a variety of weapons systems. The Air Force achieved its most important goal – independence from the US Army – becoming the United States Air Force in September of 1947, but could not remain as the sole arbiter of nuclear delivery in wartime or the sole arbiter of the military aspects of nuclear policy in peace and war (even the Air Force recognized that, their position having been mostly political show in the first place). The navy was able to recover their poise, and got their super-carriers in the end as well. The military also entered a new era under the umbrella of the new Department of Defense, a creation that did much to solve the inter-service bickering over nuclear weapons, if nothing else. With the next mortal enemy – the Soviet Union and its much-oppressed lackeys – already in focus for the US military, the navy

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took the first steps toward nuclear capability by using what it had available that could be used to evaluate how they could plan future ships and systems to incorporate the nuclear option.

The navy's entry into the nuclear age was greatly aided by three ships that the navy also almost didn't get – the new Midway-class aircraft carriers – none of which were completed in time for WW II but all of which had entered the fleet in the two years following the end of the war despite serious consideration during the war to cancelling them in favor of more Essex-class ships. The USS Midway, Franklin D. Roosevelt and Coral Sea (CVB – later CVA – 41, 42 and 43) were far larger than the Essex class carriers that had been the backbone of the wartime fast carrier task forces, and had an armored flight deck, making them ideal candidates for experiments with both the new jets and atomic weapons. The Midways were not perfect ships – the heavy flight deck reduced their freeboard and they were messily wet on the flight deck and hanger bay in a seaway for example, and they had other operational problems, resolved, as usual, by experience and modifications. At 968' long, with a 136' beam and weighing in at around 64,000 tons, with a capacity for carrying about 130 modern aircraft, the Midways, once considered by many naval experts to be “too big” and unnecessary, turned out to be exactly what was needed to push the navy into the nuclear age, particularly as it was going to be the mid 1950s before the first of the Forrestal class “super-carriers” would sail the seas. As it turned out their size worked in their favor, making them easier to modify to meet the space and weight requirements of the new jet and nuclear age. Originally equipped with a massive anti-aircraft battery of 18 of the new 5” 54-caliber guns and 21 quad 40mm (soon replaced by twin 3”/50 cal. weapons) and having an armored hull, these ships could, and did, sacrifice these features, no longer considered primary items in the defense of the ships, to modernizations that made them fully capable of jet operations and the carrying of nuclear weapons at relatively little cost in comparison to new construction.

The Midway class aircraft carriers would serve as the test beds for operational experiments in handling jet aircraft and nuclear weapons for several years while the navy awaited the first of their super-carriers, the Forrestal class, which were the follow on to the abortive USS United States, cancelled in favor of the Air Force's huge B-36 bomber (that, despite the Air Force's faith in the weapon, would be quickly overcome by the jet age and consigned to the scrap heap without ever becoming the super-bomber the Air Force had thought it would be). The lessons of the Midways would be passed directly to the Essex class carriers which would benefit in turn from the new jets being developed and from the reduction in size of nuclear weapons to dimensions easily handled by carrier-based aircraft. Following the Korean war, the Essex class ships that remained in first line attack carrier and anti-submarine warfare (ASW) roles after extensive reconstruction would all be nuclear capable and would remain in front line service and nuclear-capable well into the 1970s until gradually replaced by the Forrestals and later classes.

The big new carriers began the process of evolving into the jet-age nuclear capable world on 21 July 1946 when a McDonnell FD-1 Phantom jet landed aboard the Franklin D. Roosevelt, showing that carriers could handle jet aircraft. The transition was not going to be that easy

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however. As Norman Friedman pointed out regarding jet aircraft in “United States Aircraft Carriers: A Design History”, p. 287:

“They accelerated far too slowly and had too little low-speed lift for conventional rolling takeoffs. They would have to be catapulted, and their catapults would have to be substantially more powerful, and therefore much longer and heavier than the H-4s of the Essex and Midway classes. Landing speeds would also rise, requiring heavier and more powerful arresting gear.”

The problem of higher landing speeds and bigger and heavier aircraft also made for serious problems with the potential for disastrous deck crashes on a straight deck carrier, a problem only solvable by the angled deck, which the British were soon so kind as to develop in a practical form. (I doubt the United States navy ever adapted an idea from a foreign navy so quickly as the angled deck. It was the perfect solution to the problem.) Jets also burned fuel at a higher rate than propeller driven aircraft, and this made for a need for much more fuel storage on already crowded vessels. All of these problems would be solved in the interim on both the Midway and Essex class ships as they were modernized and the new carriers were easily adapted to these new circumstances because of their enormous size.

While the problems of handling jet aircraft were considered, the navy began experimenting with nuclear capability with the only aircraft they had that could carry the existing nuclear weapons (by this time, the Mk 3 and slightly later MK 4 bomb), the P2V Neptune, a 70,000 lb. twin-engine propeller aircraft originally designed for long-range patrol and ASW work. Its exceptional range made it the only possible candidate for a nuclear mission by the navy until the advent of the AJ-1 Savage, also a twin engine propeller aircraft (augmented by a turbojet in the fuselage) designed specifically as a strategic navy bomber. 12 P2Vs were modified by the navy to carry the early Mk 3 and Mk 4 bombs.

On 27 April 1948 two P2V Neptune aircraft were launched from the USS Coral Sea off Norfolk Virginia using jet-assisted takeoffs (JATO). (These aircraft had been loaded on the carrier while in port as they were far too large and heavy to land on the carrier.) Shore-based P2V exercises were also conducted with simulated nuclear delivery missions.

During January-March of 1949, a P2V-3 Neptune launched from the USS Midway off Norfolk, flew to the Panama Canal, over Corpus Christi, Texas and on to San Diego, California, a 4,800 mile non-stop flight completed in just under 26 hours, demonstrating at least an embryonic nuclear-strike capability on the part of the navy. Of course, this was done with an aircraft that could not be permanently deployed aboard the carrier. In the event of war, they would have to be loaded aboard ship and taken to the scene of the action and after launch could not return to the carrier for follow-on missions. Still, the navy could deliver and atomic bomb in extreme circumstances. (The records do not show that either of these early flights included carrying a nuclear “shape” as part of the exercise. “Shape” was a euphemism for a training weapon of the right size and weight without nuclear or high explosive components.)

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However, on 7 March 1949 a P2V-3C launched from the USS Coral Sea and flew across the United States carrying “a 10,000 lb. load of dummy bombs” (probably a Mk 3/4 shape) making a simulated nuclear drop probably at China Lake and returned non-stop, landing at Naval Air Station Patuxent River, Maryland. This was probably the first full “take it out and drop it test” of a training nuclear bomb from a carrier, although the records are a bit hazy on exactly what occurred. Since the plane returned non-stop, the 10,000 lb load must have been dropped.

The navy made a huge step in nuclear capability on 21 April 1950 with the first take-off of an AJ-1 Savage attack bomber from the USS Coral Sea. The first AJ squadron completed carrier qualifications aboard this ship by August of that year, marking the introduction of a true carrier-based long-range attack bomber to carrier operations. The AJ was a huge aircraft by comparison to the modern fighters and attack aircraft carried aboard aircraft carriers at this time (F-4s, F-8s and the less than satisfactory SB2C, soon being replaced by their jet equivalents) and even with folding wings and tail was very difficult to man-handle aboard ship. This and the fact that carrying them requiring deleting up to 30 other aircraft from the ship in order to accommodate three or four Savages made them extremely unpopular in the fleet. The fact that the aircraft had props and a jet made for complex handling issues as well.

During this period the three Midway class carriers were also docked for ship upgrades designed to accommodate nuclear weapons, including creation of forward and aft magazine spaces specifically for nuclear weapons, strengthening of the flight decks to take the much heavier aircraft such as the AJ and the new jets coming on line, and rebuilding the forward bomb elevator to accommodate “a package 15 feet long weighing 16,000 lbs.” (Friedman, p. 291). The decks of the nuclear weapons magazines were drilled and tapped so that the bomb dollies carrying the weapons could be lifted, their wheels removed, and then set on the deck and bolted down. Because these dollies would have to be man-handled aboard a pitching and rolling ship, they were modified from their shore-based brethren in being beefed-up with heavier brakes of the “dead man” variety – if the weapon was not under positive human control in its dolly, the brakes would immediately lock up. Magazine handling equipment such as the overhead cranes were operated by high-pressure air instead of electricity or hydraulics, another very important safety factor. Nuclear weapons spaces also included air-conditioning systems completely isolated from the other ship's systems and vented overboard, a safety factor in case of incidents within a magazine involving release of radiation. These spaces had enhanced fire-fighting capability built in as well rather than depend on external damage control assets being able to arrive on time during a fire. And of course dividing the nuclear weapons storage into two widely-separated areas was a big safety factor in handling these weapons both from the standpoint of internal accidents and battle damage.

The shipboard nuclear magazines and their contents required very high security in the form of specialized locks, alarm systems and access controls and rules, backed up by a continuous US Marine guard with bad attitudes towards those not possessing the proper access credentials. Lethal force in protecting the nuclear weapons spaces was authorized.

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The navy had not neglected the training of personnel, developing a training program primarily at Sandia Base, New Mexico to train and qualify officers and men in the assembly, test, and preparation of nuclear weapons for strike operations, and of course all the emergency and safety training that went with such responsibility, particularly as the early weapons, with their huge amounts of sensitive high explosives did not have the safety factors built in to them that exist today. Nuclear weapons “teams” were developed who would ship out and deploy with their equipment to a ship that would be loaded with nuclear weapons prior to deployment to the fleet. The crews would return when the deployment was completed and the weapons returned to storage. This was a very time-consuming and expensive venture to deploy a large team of men and the necessary test and other equipment to the fleet and return, and this process was soon replaced by the simple expedient of attaching the nuclear weapons qualified personnel permanently to the ship, along with all the necessary equipment.

By the early 1950s, with ships equipped to store and deploy nuclear weapons, an aircraft that could carry them, and trained personnel to get the job done, the U.S. Navy had fully entered the nuclear age, although with only a limited strike role available. Strategic long-range penetration of enemy territory would remain the province of the Air Force for another few years. And on the horizon were ballistic missiles, cruise missiles and other delivery systems that would eventually result in all the American services having “strategic and tactical” nuclear capabilities almost beyond comprehension.

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Part 3: The First “New” Bomb

By the early 1950s, the U.S. Navy had established itself as a nuclear-capable force, with delivery aircraft in production and ships modified to store, assemble and deploy nuclear weapons. Only the large, cumbersome Mk 3 and Mk 4 bombs were available for use, and these weapons were by no means ideal for military service due to their short “shelf life” once assembled, the labor and manpower-intensive process of assembly and test and of course their weight and size. The main delivery aircraft operating from carriers was the AJ Savage, a huge and cumbersome aircraft for use on a carrier. Even the large Midways had problems with those aircraft in handling and storage. Still, the navy could deliver nuclear weapons to the maximum range dictated by the Savage (2,470 miles carrying one Mk 5) or the longer-ranged P2V. While the P2V Neptune ASW/patrol aircraft could also carry the current nuclear weapons, and several aircraft were modified for this duty, the advent of the Savage and even more capable aircraft over the next few years kept the P2V pretty much on the periphery of the nuclear strike picture. They would probably only have been used for the ultimate emergency.

This section continues covering the bombs used by the Navy, from oldest to newest, and will be followed by the navy's anti-submarine weapons, missiles and lastly the strategic ICBM/IRBM warheads. Each section will cover the weapon (bomb/warhead) itself and, briefly, the delivery system for that weapon, be it an aircraft or other system. (Bombs and warheads are basically synonymous, whereas other nuclear delivery systems are not so congruent.) One of the difficulties with nuclear delivery systems is the official designations assigned to them. The designations for aircraft have changed at least twice since the end of WWII and the designations for missiles and other systems have also been prone to bureaucratic revisions over time. Here the specific designation for the aircraft/weapon in use at the time the weapon was in the active inventory is used, since everything is pretty easy to find on the web. If there was a “popular” name for a system, that will be included (“Lulu” “Hotpoint,” etc.). Just to make matters even more complex, there are the designations applied to the actual weapons themselves, which can be somewhat interchangeable – “B” for bomb, “W” for warhead, and the MK (Mark) identifier used with many weapons. (The MK 101 “Lulu” is a good example – the navy designated it as the MK 101 depth bomb, but it never carried a “B” designation, and it had the W-34 warhead as its nuclear component.)

Based on the new nuclear bombs entering the inventory early in the 1950s, it becomes obvious that the military and scientific communities were closely collaborating on weapons designs in order to reduce weapon size, increase availability times, ease the job of delivering weapons, reduce the risk to the delivery aircraft, and increase the safety factors involved in handling weapons. Up to this point, the military had to basically accept what the weaponeers and scientists had been able to design given the known physics and engineering capabilities of the time. That would now change, as the military began to understand nuclear weapons physics and mechanics, enabling them to specify exactly what they thought was needed to ensure they could deliver the goods against an enemy target. It was a slow process, but the scientific community was well capable of the science and engineering necessary to produce these weapons in amazing variety and pretty consistent high quality to meet specific military needs.

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Progress in weapons manufacture was greatly aided by the fact that nuclear weapons had about the highest budget priority there was for many years, money spent not only on weapons but the manufacturing infrastructure as well.

(The ability to reduce the size of both fission and fusion weapons over the past 60 years has been staggering, and has used a variety of techniques, some still highly classified. The early improvements revolved primarily around developing better high explosive packages using new types of explosives coupled with reducing the size of detonators and their electrical harnesses. Weapons also benefitted from being able to reduce the size and weight of the weapon's electronic and other systems. Early yield increases for fission weapons usually revolved around better nuclear capsule designs and the ability to “boost” yields by various means, usually gas boosting using tritium and/or deuterium.)

The Mk 5/B-5

In 1948, the Los Alamos laboratory began design work on a new bomb that would be a big improvement in some areas over the Fat Man derivatives then in the stockpile. The warhead component was tested during Operation Greenhouse, Test Easy, on 21 April 1951. With a test yield of about 47 kt, the weapon had about doubled the output of previous weapons. The test device became the Mk 5/B-5 bomb, which entered the inventory beginning in May of 1952 and was the first lightweight small diameter nuclear weapon. Weighing between 3025 and 3175 lbs depending on Mod and core, the weapons was 10' 9” long and 3' 8” in diameter. The bomb version used composite cores and had variable yields of 6, 16, 55, 60, 100, and 120 kt.

The Mk 5 was the first weapon to use an automatic IFI instead of the previous method of hand-inserting the core into the weapon. The automatic IFI had the core installed in a separate holding tray when the bomb was prepped; this kept the core away from the high explosive package. The tray would insert the core in the bomb at the appropriate time by electrical command from the aircraft. For a nuclear weapon to work the core must be exactly centered within the high explosive package in order for implosion to occur; any other arrangement, such as when the IFI had the core outside the weapon, would not cause a nuclear detonation if the weapon explosives detonated in an accident scenario. While there would be a local scattering of highly radioactive materials about in this situation, that would be a far better scenario to clean up than an accidentally incinerated military base and city. The PR would be easier to deal with as well.

About 140 Mk 5 weapons were produced in 1952-53 and these weapons eventually had four Mods. (As with many weapons, later Mods were usually made from the major components of the previous version, with whatever improvements of the new Mod added in. Old Mods would “retire” new Mods would take over, and the inventory remained about the same). The bomb was somewhat restricted in use because it was limited to high-altitude delivery and was fused only for an air burst option, there were no contact detonators. The bomb was internal carry only, and thus could not be used with supersonic aircraft. With no competing weapons in the inventory at the time, these limitations were moot.

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A Mk 5 was used as the “primary” (nuclear fusion initiator) in the early Ivy Mike thermonuclear test on 1 November 1952. The nuclear package was also adapted as the warhead for both the Matador and Regulus missiles and these bombs were also supplied to Great Britain under Project E for use with the Valiant bombers. The B-5 was withdrawn from inventory starting in 1957, with the last weapon retired by 1963.

During this bombs active service with the navy, the AJ-1 and -2 Savage was the primary carrier, bolstered by the all-jet A-3 Skywarrior which was a far superior aircraft capable of 620+ mph and with a 2,300 mile tactical range. The Skywarrior came into service in 1956, just before the MK 5 was starting to be withdrawn from service.

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Part 4: More Bombs

The MK 6 Bomb

The MK 6 bomb was the first American nuclear weapon to be produced in large numbers, with around 1100 built between July 1951 and April 1954 – and indication of the ability of the weapons manufacturing infrastructure to meet what were felt to be the needs of the nuclear stockpile.

The MK 6 was 10' 8” long and 5' 10” in diameter and weighed between 7600 and 8500 lbs depending on the core used. An obvious lineal descendant of the last “Fat Man” type bomb, the MK 4, the Mk 6 was a far better weapon, providing greatly increased yields at considerably less weight. Up to 3000 lbs of weight had been saved by making the bomb casing out of aluminum instead of 3/8” mild steel. The MK 6 was produced in four Mods. Weapon yields varied depending on the core used and were 8, 26, 80, 154, 160 kt. (I've never been able to figure out why a weapon would have high-yield cores whose difference in yield would only be about 6kt. “What's the point?” comes to mind).

One of the improvements of the MK 6 over the MK 4 and 5 was the ability to alter the burst altitude of the weapon in flight. It also had a contact fusing option in addition to the airburst option. The bomb's main drawback (and that of its upgraded sister, the MK 18, discussed later) was the fact that it used large amounts of fissionable material (plutonium) to achieve the higher yields. As the newer, lighter weight fission weapons became available, along with the first thermonuclear weapons, the Mk 6 started to be withdrawn from service as early as 1955 for the Mod 1 and by 1957 the last Mod 4 had been retired. The cores of these weapons, like many others were refurbished and used in other weapons and the Mk 6 bomb casing was used for the newer Mk 18 bomb. The bomb could be delivered by the AJ Savage and A3 Skywarrior.

The MK 7 Bomb

The MK 7 bomb was the first of the true “tactical” nuclear weapons (not designed for the strategic attack role) deployed by the United States and the first to be used by all three armed services. In addition to the bomb version, the warhead was also used in the Army's Corporal and Honest John missiles and in the Navy's BOAR (Bureau of Ordnance Atomic Rocket) and the Betty depth charge (both will be covered later). The MK 7 was designed for external carriage by fighter/attack aircraft and had a retractable lower fin so that the bomb would not “scrape” during a catapult launch. Measuring 15' 3” long by 31.5” in diameter and weighing 1645 – 1700 lbs, the bomb had five yields – 8, 19, 22, 30 and 61 kt. Produced in 10 different Mods, the bomb was in the active inventory from 1952 – 1967. Versions of this weapon were supplied to Great Britain under Project “E” for the Canberra B(I).8 from 1960 – 1968. This weapon could be carried by a wide selection of naval aircraft, including the AD, A3P, AJ, F2H (Banshee), F3H (Demon), F7U-3 (Cutlass), P5M (Mariner), P2V (both the bomb and the Betty depth bomb), S2F (Betty) and even the HSS-1 helicopter (Betty). About 1800 MK 7s were produced.

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The MK 8/B-8 “Elsie” Bomb

The MK 8 bomb was the first “penetrator” bomb. Nicknamed “Elsie” for “LC” (light case)” the MK 8 was developed at Los Alamos specifically as a naval weapon for use against “hardened” targets like submarine pens. A much-improved “Little Boy” gun type weapon not so wasteful of fissile material, it was the first nuclear weapon designed to detonate after hitting the ground as opposed to an airburst or instant ground contact detonation, being equipped with a delayed action fuse. The bomb was 9' to 11' long and 14.5” in diameter. The yield was variable between 20 to 30 kt. The weapon could be carried internally or externally, but was not designed for supersonic speeds and was therefore quickly replaced in the inventory by the later B-11 (also known in the Navy as the MK 91). Only about 40 MK 8s were produced between 1951 and May 1953, with the last weapons withdrawn from the inventory in May 1957. They could be carried by the AD, AJ, A3D, A4D (Skyhawk, later A4), F2H, F3H and F7U-3.

The B-11 (MK 91) Bomb

The MK 91 bomb was an improved MK 11 gun-type penetrator weapon which had a sharp heavy nose, unlike the flattened nose of its predecessor. Also a Los Alamos design, the bomb was credited with being able to penetrate 22 feet of reinforced concrete or up to 120 feet of clay soil, far exceeding the capabilities of the MK 8. It could also be carried externally at supersonic speeds. The bomb had a delayed action fuse that would detonate up to 2 minutes after impact. Like the MK 8, only about 40 of these weapons were produced through 1957 as lightweight thermonuclear weapons came on line such as the MK 43, which also had some penetrative capabilities. By June of 1960 these bombs had been removed from the active inventory. The MK 11 was 12' 2” long and 14” in diameter, weighing up to 3500 lbs. and had a variable yield between 10 and 20 kt. The bomb could be carried by the AD, AJ, A3D, A4D, F2H and F3H.

The MK 12 Bomb

The MK 12 bomb was developed by Los Alamos in response to a Navy requirement for a light tactical weapon that could be delivered by supersonic fighter aircraft as well as subsonic attack aircraft. A major improvement over the MK 7, the Mk 12 could be delivered at speeds up to mach 1.4 and had the same fusing options – air and ground burst. Produced in three Mods, the MK 12 was 13' long and 22” in diameter, weighing 1200 lbs. Yield was 12 or 14 kt and the bomb was reportedly the first to use a beryllium tamper to reduce yield. (A "tamper" absorbs neutrons, making less of them available for the nuclear chain reaction, causing less efficient nuclear burning and a reduced yield. Boosting has the opposite effect.) The bomb first entered the inventory in 1954 and was finally retired by 1963, some 250 bombs having been produced. Though the bomb was an improvement on the MK 7, it did not replace the MK 7, merely supplemented it. Delivery aircraft were the AJ, A3D, A4D, F9F-8B (Cougar), F3H, F7U-3 and FJ4-B (Fury).

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Part 5: The Beginning of the Megaton Era

Before continuing on with the eight remaining nuclear bombs available to the United States Navy during the nuclear era and then on to missiles and other weapons, we should step back a bit from bomb production and take another look at the historical context within which the nuclear weapons program evolved from the early 1950s to the present. The transition from the early fission weapons to far more destructive fusion weapons is a good starting point.

By the early 1950s, the thermonuclear weapon had become a reality. The principle of nuclear fusion developed by Stanisalw Ulam and Edward Teller that provided the method by which a nuclear detonation could initiate thermomuclear burning resulted in early devices being tested by the United States beginning in November of 1952 at Bikini and Eniwetok; at first a cryogenic proof of theory test (using liquid deuterium and tritium, totally impractical as a bomb) and shortly thereafter the first "dry" lithium/deuterium weapon which is the working principle of all subsequent thermonuclear weapons. At first these "H-bombs" were huge and could only be carried by the Air Force's B-36 bomber, such as the 21-ton MK 17 with its 13.5 MT yield (MT = one million tons of TNT). In one gesture of a magical arm, the nuclear genie had upgraded itslef from being able to incinerate most of a city to completely incinerating a huge piece of real estate from the face of the Earth and poisoning it beyond habitation for many years to boot – a rather scary proposition at best.

Methods for reducing the size of these thermonuclear bombs were rapidly developed for bombs and missile warheads, the process evolving even faster than that for fission weapons which, for example, had reduced the first Fat Man type bombs with roughly a 20 kt yield for almost 10,000 lbs of bomb to around 60 kt in a bomb weighing about 1700 lbs. by 1952. It was only a few years before the American military could field weapons with yields of 2 megatons in a weapon weighing around 3300 lbs and deliverable by even the smaller tactical aircraft as well as the big bombers. (The development of missiles to deliver comparatively lightweight warheads also proceeded apace, with the emplacement of the first ballistic missiles able to deliver thermonuclear destruction from thousands of miles away just a few years in the future.)

Many factors went into the reduction in size, including "smarter" methods of initiating and sustaining a fusion reaction, reducing the size of the nuclear "primary" in a fusion weapon, and of course huge advances in miniaturizing the electronic and mechanical "packages" that controlled a weapon and permitted it to detonate when all factors had been successfully input into the arming and fusing system, factors that included ever more effective and sophisticated safety parameters.

Congruent with the development of the thermonuclear weapon were great improvements in the "standard" fission weapons of the day that greatly increased their yield with little modification to the weapons internal systems, particularly the use of "boosting" systems. The necessary combination of a fission primary to initiate thermonuclear burning in a fusion "secondary" also allowed for more options in the deliverable yield of weapons, yields which could eventually be adjusted within certain parameters as needed prior to the weapon being

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delivered. It is to be noted that the Soviet Union, aided by their continual espionage, but in the end independently under the guidance of the brilliant Igor Kurchatov and his successors, were able to develop their own thermonuclear weapons and pursue their own "arsenal of communism" while we pursued our "arsenal of democracy". The idiotic levels to which this pursuit was carried only became apparent on both sides of the Iron Curtain much later, particularly after the Cuban Missile Crisis wake-up call for both sides.

Concurrent with the development of thermonuclear weapons were the development of versions of these weapons that would create far more human destruction and less physical destruction (the so-called "neutron bomb") as well as even worse scenarios that would salt the Earth with fatal levels of radiation for many years ("dirty" bombs). While the former might have some military merit, the latter was just plain stupid. Yet those weapons either entered the inventory or existing weapons could be quickly modified to these standards if needed.

The advent of thermonuclear weapons had clearly escalated the potential to wipe out the human race from a probability to almost a certainty, along with wiping out almost everything else that lived and breathed. Thermonuclear weapons brought about the absurdity of having weapons to "protect" a nation that could eventually wipe that nation out even if used only against an enemy thousands of miles away, not even counting the results of that country's nuclear response in the equation. This is not a good set of parameters to use in measuring the potential for humans to outgrow their tendency to slaughter each other on the flimsiest of religious or social pretexts and evolve into their much-avowed potential to be peace-loving and productive products of evolution.

Of course, this "nuclear winter" scenario that thermonuclear weapons had made possible was not recognized or even readily apparent in the 1950s and early 1960s – when the free world approached its most dangerous crisis with the American military quite willing to commit to nuclear war should the "other side" make a fatal misstep with their nuclear weapons in Cuba. This makes that narrow miss even more historically relevant than just the potential for a nuclear exchange. Fortunately, the Cuban crisis, coupled with growing scientific recognition on both sides of the Iron Curtain that we were setting ourselves up for total elimination as a species finally got the lights on, and led directly to the tentative steps at nuclear reconciliation that now hold among the governments of the world – barely. The concept of "MAD" – mutually assured destruction – that evolved in this era as the justification for the massive nuclear arsenal could not have been more aptly named. It was infantile in the extreme as a policy designed to deter evil and the horrors of nuclear war. The policy could not prevent war, just make sure there were no winners, and even politicians and statesmen can recognize the folly of no-win situations.

But, in the meantime, nuclear testing of fission and fusion weapons continued apace at Bikini, Eniwetok, Nevada and a few other places (very few) and of course the Russians had their own program of incinerating test sites with gay abandon as well. The United States confined their surface tests of thermonuclear weapons to the Pacific Islands (managing to poison several islands and their inhabitants in the process) while the Russians basically set off whatever they

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wanted in their interior test sites regardless; the prevailing winds blew toward China anyway. Most of these tests were more "proof of systems" tests – i.e., proof of the operating/delivery system, be it a bomb or missile – rather than any proof of the fission/fusion process, although refinements were made in these areas as well as scientific knowledge grew. The Soviets, ever anxious for the communist system to "top" that of the obviously doomed and decadent imperialist West, eventually detonated a 58 MT air-dropped thermonuclear weapon (the Tsar Bomba) over Novaya Zemlya, proving to the world they were without doubt the biggest and baddest kids on the block and ready to rule the world as soon as everybody else kow-towed to their obvious might. (The unfortunate difference between fusion weapons and fission weapons is that while fission weapons are limited to a top end around 500kt, thermonuclear weapons have no top end. The Tsar Bomba was actually a reduced version of the original proposal which would have yielded 100 megatons.) Probably the only things that Soviet test proved was that you could punch a hole in the Earth's atmosphere all the way to the edge of space and irradiate a huge area for no good reason whatsoever. Communism at its best, in other words.

Anyone who uses Google Earth to take a look at the massively cratered Nevada Test Center northwest of Las Vegas, Nevada or the islands of Bikini and Eniwetok will get a good idea of the extent of this testing. In my opinion, a lot of the testing was in the end unnecessary, particularly above ground tests, but it seems the paranoia generated by the conflict between the communist world and the free world knew no bounds in those days. The frantic military scrambling to avoid any "bomber gap" or "missile gap" and to prevent communist domination of the world powered the government into total overkill, some of this partly because the military was trying to justify its existence and budgets regardless of the actual threat posed by the opposition, a fact that began to become apparent when spy planes and satellites started to reveal the true decayed situation within the Soviet Union for all to see. Bomb shelters and "duck and cover" nuclear paranoia and absurd sci-fi movies featuring giant insects run amok abounded in the America of the 50s and, again in my opinion, were useless in facing up to the obvious. The only possible reason I can think of to duck and cover in those days would be to kiss your sorry ass goodbye. The same criterion applies today. And humans, obviously, are inherently far more dangerous antagonists than any oversize Technicolor ant could ever be. Even Godzilla knows that.

Complimenting the absurdity of so much testing of weapons was the equally absurd (again, in my opinion) approach of the American government to the safety of these tests in regard to the public at large. (The Soviet and its successor government's response was even more absurd – they didn't care then, and care even less now.) One can draw a comparison to the destruction of two Japanese cities, with the subsequent radiation poisoning and death of thousands not directly or fatally exposed to the blast and heat of the detonation over a period of years to the assumption by the government that detonating even larger weapons within a few hundred miles of population centers like Las Vegas and cities "downwind" of the test site posed no real risk to the public, despite the even more recent examples of events at Bikini and nearby islands compounding the evidence found in Japan. Coupled with this has been the continual foot-dragging of the government in recognizing the effects of these weapons tests on the thousands of military personnel and civilian workers who participated in these tests as well as the Pacific

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islanders affected by fallout. Some compensation has been granted in various forms to the nuclear veterans groups following what little was done for the Pacific islanders. The plight of the South Pacific islanders has been well-documented in a book on the subject, that of the nuclear veterans less so. It's still a struggle, but progress has been made, far too late and I'm sure many dollars short for many. Like many governments the world over, ours is sadly no different in their reluctance to admit mistakes that adversely affect the health of the population and even more reluctant to open the coin purse `in compensation.

While one can justify the existence of nuclear and thermonuclear weapons as a means of ultimate defense against the encroachment of total evil, justifying the quantities of weapons needed to achieve this goal, and the methods of testing these weapons is not subject to the same easy logic and justification. We managed to poison our environment with these weapons just by testing them, without having ever gone to war with them. That's pretty stupid by any criteria of evaluation. While the absence of nuclear war has been a nice bonus of the latter half

of 20th

century history, we could have done completely without the extremes of poisonous testing. However, humanity, ever willing to postpone serious decisions in the hopes the problem goes away and thereby learning the hard way that such policies only mean having to make harder and far less palatable decisions from among far worse options later, has finally signed treaties and reduced arsenals from the world-obliterating numbers of the past. The communist system collapsed under the weight of its own financial burdens and from the fact that the Soviet world and its imitators were not communist systems but rather systems of harsh totalitarian government by a privileged and criminal few – the diametrical opposite of what Marx and Engels had proposed. The free world came out on top because freedom is just so much more fun than totalitarianism for all concerned, and learned that it did not need an arsenal that could destroy the entire world fifteen times over, did not need to spend trillions of dollars as a hedge against "the other guy." The Soviets went under simply because their system, regardless of how much it was forced to function by the threats of the gulag and the basement of the Lubyanka, simply would not.

With that historical turnaround in hand, we now only face the modern and possibly more dangerous absurdity of having to share our world with fanatical religious zealots who are convinced that only their religion should reign supreme, and that possession of nuclear weapons might go a long way toward realizing that goal. They see only the weapons themselves as an adjunct to the Sword of Allah, a threat to be bandied about along with their concept of jihad against more libertarian principles; they do not see the lessons that the development of nuclear weapons taught both the now defunct Soviet Union and the United States. This makes them far more dangerous than our former antagonists because they are, in the end, not very bright when it comes to the lessons of history, and are only interested in promoting themselves as the epitome of human social and religious evolution regardless of any potential consequences. This highly unstable and erratic view held by a considerable majority in the Islamic world is extremely hazardous to the overall health and well-being of the world in general, and themselves in particular. These wielders of jihad and absurd social conservatism have about them the same suicidal flavor of Japan's old Imperial Army, willing in the end to face national destruction rather than confront the personal loss of face inherent in recognizing that

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they are not the be-all and end-all of human civilization by any means. This is the most dangerous view of the world imaginable, and a threat that cannot be ignored, deferred to, or resolved by weak and conciliatory appeasement built around fantasies of "peace in our time." That being the case, the presence of nuclear weapons in the arsenal of the free world continues to be not only a prudent and sensible course of action for the foreseeable future but an absolute necessity.

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Part 6: Still More Bombs

From the late 1940s to the mid-1950s, the U.S. Navy had slowly developed its nuclear delivery capability from carrier-borne aircraft delivery of very heavy weapons by large aircraft less than ideal for carrier deployment to the ability to deliver both "strategic" and "tactical" strikes from a large number of far more suitable aircraft. This section will finish up with the bombs that fit within this era of naval nuclear capability and then future sections will move on to the parallel development and deployment of specialized nuclear weapons for the anti-submarine role, fleet air defense and anti-shipping strike (roles that opened the nuclear option to fleet units other than aircraft carriers) and finally to what would evolve into a long-range strategic strike role with the advent of first the Polaris ICBM program and its descendants the Poseidon and Trident.

MK 105 "Hotpoint" (and the W-34 Warhead)

The Mk 105 Hotpoint bomb (a navy designation) was the first nuclear weapon developed for "laydown" delivery where the bomb would be dropped and retarded by a parachute until it would soft land instead of impact at high speed. The outer nose casing of this weapon would be blown off by a small charge just prior to impact and an inner reinforced steel "cookie-cutter" nose would absorb the shock of impact. Detonation of the weapon was via a time delay system that allowed for both airburst and delayed ground burst. The timer delay also allowed the Hotpoint to be used as a nuclear depth charge for anti-submarine and anti-ship use. (Underwater detonations were not only intended to be fatal for submarines, but as anti-task force weapons if needed, a fact made obvious by that famous film of the Operation Crossroads Baker detonation.)

The MK 105 could be carried internally or externally on all the anti-submarine and most attack aircraft in the navy inventory, measuring either 8' or 12' long depending on how it was carried. The bomb was 19" in diameter and weighed about 1700 lbs. Yield was 10 – 15 kt. The MK 105, released in two Mods, used the W-34 warhead of which 600 were manufactured specifically for this bomb out of a total of 3600 W-34s manufactured between 1958 and 1962 for navy weapons that included the MK 101 depth charge and the MK 45 Astor torpedo. The MK 105 and the contemporary MK 101 "Lulu" depth charge (which had hydrostatic fusing) entered the navy inventory beginning in early 1958 and are historically significant in the nuclear weapons program because of the W-34 warhead used in both. This warhead was the direct result of a navy Bureau of Ordnance request in May of 1954 for development of a small depth bomb. The navy's weapons specialists (particularly famed WWII submarine commander CPT Henry Glass Munson who had earned a Master's degree in nuclear physics in 1952) contributed directly to the design of this warhead, demonstrating the increasing coordination between the military end-users and the civilian bomb makers, a working relationship of great importance to the strategic security of the U.S. in the years to come.

The Los Alamos Laboratory was the prime developer of this weapon and conducted tests (Operation Teapot) at the Nevada Test site in February – May 1955 of a small boosted-implosion

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device also using a different method of initiating the neutron pulse that began the nuclear burning process among other system improvements. The W-34 warhead was also indicative of the great improvements being made in fielding weapons that needed very little "prep" time to have them ready to load on an aircraft and little maintenance required for keeping them active in the inventory until needed. Nuclear weapons have become more and more "canned" and ready to go ever since. The role of the nuclear weapons specialist, engaged in maintenance and care of deployed weapons, has all but disappeared from the navy as a consequence.

The weapon used a fission design nicknamed "Python." As finally produced as the warhead for several weapons, the W-34 was by far the most scientifically elegant and utilitarian fission weapon of its day. In addition to its application to three navy weapons, the W-34 warhead was also used as the primary fission device in several thermonuclear weapons, including the MK 28 bomb. The W-34 also featured in several British weapons including a fission bomb and as the primary in a British thermonuclear weapon based on the MK 28.

The W-34 warhead was 32" inches long, 17" in diameter and weighed around 320 lbs. With a yield of around 15 kt, the comparison to the "Little Boy" weapon with the same yield is indicative of the enormous advances made in ten years regarding the reduction of weapon sizes and weights while still achieving the required yields.

(The W-34 warhead is also notable as the first warhead this writer ever worked on as a "newbie" nuclear weapons specialist at the navy's Nuclear Weapons Training Center at Sandia Base, New Mexico. )

The MK 105 could be carried by the AD in the attack role and the P2V, P3V, P5M, S2F and the HSS-2 helicopter in the ASW role. The MK 105 remained in the navy inventory until 1965, primarily as a laydown weapon, as the MK 101 Lulu had taken over the first-line role as the navy's nuclear depth charge.

MK 15 Bomb

The MK 15 (B15) bomb was the first "lightweight" thermonuclear weapon deployed and the first "production line" fusion weapon, some 1200 being produced between April 1955 and February 1957. (The production of 1200 megaton-range thermonuclear weapons in the space of two years says all that need be said regarding the capabilities of the weapons manufacturing infrastructure in the United States at the time.)

During development the B-15 warhead was nicknamed "Zombie" and was tested in Operation Castle, shot Nectar, on 13 May 1954, yielding 1.69 MT, a yield that increased considerably in the production weapon. The MK 15 was still a somewhat limited weapon in that it was fused only for air and ground burst and had no retard capability. Produced in two Mods, the bomb entered service with the navy in April of 1955, with the last withdrawn from service in 1965. (The MK 15 was also supplied to Great Britain under Project "E".)

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The bomb weighed between 6850 – 7600 lbs. and was about 11' 8" long and 34.5" in diameter. Yield was 3.4 MT (about 150 times more powerful than the Fat Man bomb). The bomb could be carried by the AJ and the A3D. (In my estimation, the ability of the AJ to escape the blast of a weapon this size approached zero, and the A3D only slightly less so, a fact probably thoroughly depressing to aircraft crews, particularly with a weapon with no parachute retard capability.)

With the deployment of this weapon to naval operations, the line between the "tactical" role expected of the navy in a nuclear war and the strategic role designated for the Air Force became subject to considerable blurring, a trend that would continue as the definition begin to apply more to what target was going to be hit with what weapon rather than a "role" of the services or the delivery vehicle.

MK 27 Bomb

The MK 27 bomb was the second thermonuclear weapon deployed by the US Navy, supplementing the MK 15. (The W-27 warhead was also used as the upgraded warhead for the Regulus I and II missile, the latter being canceled before it was ever deployed.) Designed for use against large strategic targets like its contemporary, the MK 27 was fused for air or ground burst. The A3 Skywarrior and the A5 Vigilante were the delivery aircraft. When employed for the A5, the bomb would have two expendable 275 gallon fuel tanks rigidly mounted to either end of the bomb. The A5 would use this fuel en route to the target and the entire package would be ejected aft on rails from the tube bomb bay of this aircraft. Theoretically, the tanks would help stabilize the bomb in its descent. This system never worked properly, and the A5 was later withdrawn from the attack role with this bomb, being converted to the reconnaissance/attack role (the A5 could still carry nuclear weapons on wing pylons if necessary, but this reduced speed considerably).

The MK 27 was in the navy inventory from November of 1958 until October of 1964, its relatively short life due to the conversion of the carrying aircraft to other roles and the retirement of the Regulus 1. The bomb was 10' 5" to 11' 10" long with a diameter of 30" and weighed between 3150 – 3300 lbs. Bomb yield was 2 MT. Produced in three Mods, about 700 weapons were built in all.

MK 28 Bomb

The MK 28 bomb was the first to be designated as a "weapons system" because it was designed to flexibly adapt to many delivery options by being assembled into any one of five different drop "shapes," although the original version was built around the B-52 bomb bay which could hold four of the internal version of these bombs. Like all the more Modern bombs, delivery option settings became possible from the electronics of the carrying aircraft rather than by on-the-ground settings that couldn't be changed in flight.

Because the MK 28 had an extremely long service life, it was produced in 20 Mods and variants and was in service long enough to undergo an improvement program to the later versions that

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added new electrical equipment, better and more insensitive high explosives in the W-34 primary, and increased safety features including three versions of the PAL safety interlocks (Permissive Action Link, basically a safety system operated only by human intervention according to strict protocols and initiated only when the President has given the orders to go to war. The MK 28 had CAT A, B and D versions depending on the bomb Mod.)

Production of this bomb began in August of 1958 and continued through May of 1966 with some 4500 bombs produced and an additional 1000 W-28 warheads produced for the Hound Dog and Mace missiles. MK 28s were supplied to Great Britain as part of Project "E" for the Valiant bomber. (The W-28 warhead was adapted by the RAF to their own bomb casing design.)

Versions of the bomb were: MK 28 IN (free-fall internal carriage); MK 28 EX (free-fall external carriage); MK 28 RE (parachute-retarded external carriage); MK 28 RI (parachute-retarded internal carriage; and the MK 28 FI (fully fused internal carriage). In each case the basic warhead assembly remained the same and the changes involved adding different fusing and parachute packages to either end of the warhead as well as different fins when needed. The external versions had fins that folded and were deployed by a small explosive charge when the bomb was released from the aircraft. This improved aerodynamics for the carrying aircraft and of course kept the bomb tail away from the flight deck when the aircraft was catapulted. The bomb was easy to maintain but came with a lot of extra "baggage" in order to convert the weapons from one delivery version to another.

Depending on the version, the bomb measured between 8' and 14' 2.5". Diameter was either 20" or 22". Weight varied from 1980 lbs. to 2349 lbs. Yields varied with the Mod and are listed as: Y1 – 1.1 to 1.45 MT; Y2 – 350 kt; Y3 – 70 kt; Y4 – no accurate figures but probably 15 kt.; and Y5 – same as Y1. For the navy, the carrying aircraft were the A-3, 4, 5, 6 and 7, the P2V and the S2F. In the inventory for some 34 years, longer than any other nuclear weapon, the older Mods started to be retired in 1975 as newer weapons entered the inventory and the last MK 28 completed disassembly in April of 1992.

The MK 28 gained international attention on 17 January 1966 when a B-52 collided with a KC-135 tanker at 30,500 feet over Spain. Seven men were killed in the accident. All four Mk 28 INs carried by the bomber dropped out of the stricken aircraft, three landing near Palomares, Spain and one in the ocean, resulting in much bad PR and the purchase and cleanup of a large chunk of Spanish soil. The bomb that dropped in the ocean was finally recovered by the navy and photos of this bomb have been published; one notes the bombs ancillary equipment is pretty battered but the warhead casing itself is intact.

MK 39

The MK 39 bomb was a direct descendant of the MK 15 with parachute retardation for low-altitude delivery and a new gas-boosted primary (probably the W-34, which had just entered production). The bomb had improved safety features such as the use of thermal batteries, which also improved maintenance and readiness. The MK 39 was another weapon supplied to

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Great Britain under Project "E" for the Valiant bomber. The bomb's warhead was tested at full yield three times during Operation Redwing in 1956 (Shot Cherokee) and Operation Hardtack 1 in 1958 (shots Teak and Orange).

The MK 39 entered production in February of 1957 and remained in the inventory until 1966. Only the A3D could carry the bomb for the navy. Produced in two Mods, the bomb was 11' 4" long with a diameter of 35" and weighed either 6650 lbs. (Mod 0) or 6750 lbs (Mod 1). Yield was 3.8 MT. 700 MK 39s were built with an additional 60 W-39 warheads built for the Redstone and Snark missiles.

MK 43

The MK 43 was a more versatile thermonuclear weapon than the larger weapons preceding it, and could be used by a wide variety of aircraft. Successor to the MK 12, and also for the MK 11 penetration bomb, the MK 43 was designed at Los Alamos in 1956, with quantity production starting in February of 1959; 1000 weapons in two Mods were produced by October of 1965 when production ceased. (MK 43s were supplied to Great Britain under Project "E" for the Canberra and Valiant.) The MK 43 had two nose configurations, an armored steel spike (Mod 0) for laydown (it could actually "stick" in the ground, and there are photos of test weapons in this Mode) and a Mod 1 nose containing radar fusing for air burst options. The MK 43 also had parachute retardation options which could be "selected out" if the free fall option was used. The MK 43 was also fitted for the rigid fuel tanks of the A5 Vigilante system, but was never employed as such as the system never worked right. Depending on the nose option, the bomb was 12' 6" or 13' 8" long with a diameter of 18" and a weight of 2060 or 2125 lbs. There were five yields available. The Y4 yield used the fission primary of the bomb only and was 70 kt. The highest yield was 1 MT. The bomb was equipped with a CAT D PAL. Delivery aircraft were the A1, A-3, A-4, A-5, A-6 and A-7.

MK 57 Bomb

The MK 57 bomb was the smallest free-fall bomb in the arsenal. Designed for special tactical strikes as well as ASW operations, this lightweight, multipurpose fission bomb was the result of a specific design request by the Navy and Marine Corps. In addition to the wide variety of navy aircraft that could carry the weapon, three NATO aircraft were also certified to use the MK 57 – the British Nimrod, Dutch P-3 and Italian Atlantic. The RAF's Tornado could also carry the MK 57. Another Los Alamos designed weapon, characteristics for the bomb were approved in December of 1959 and quantity production began in 1963 with some 3100 weapons produced in six Mods. Production ceased in May of 1967. Several Mods, particularly the NATO weapons, had the CAT B PAL device. The bomb was removed from naval vessels in 1991, although dismantling of older Mods had started in 1975. The final MK 57 was disassembled by March of 1995.

The MK 57 had selectable delivery options including free-fall air burst, parachute- retarded air burst, contact burst (bypassing the parachute) and parachute-retarded underwater burst (depth

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charge); the MK 57 was equipped with hydrostatic fusing and replaced the MK 101 Lulu in this role. The bomb had four yield options from 5 kt to a fully boosted 20 kt and was 9' 10” long and 14.75” in diameter, weighing between 490 and 510 lbs. Naval aircraft the could carry the MK 57 were the A-3, A-4, A-6 (Intruder), A-7, F-4, P-2, P-3, SH-3 (helicopter) and the QH-50C (DASH) drone helicopter. The DASH capability meant that the MK 57 could be carried by ASW ships such as the DASH-modified destroyers, the only time a bomb appeared at sea anywhere but on an aircraft carrier in the U.S. Navy.

MK 61 Bomb

Now the only nuclear bomb still available to the navy inventory, this weapon was designed as a lightweight multipurpose thermonuclear weapon used both tactically and strategically. It can be carried at high speeds by a large variety of aircraft and has been certified for use by aircraft flown by Great Britain, Italy, Belgium, the Netherlands, Turkey, Greece and Germany although none of these countries now have any of these weapons available to them. Produced in 11 Mods beginning in 1968, 3150 bombs were produced and about 1300 are still in the stockpile. The last Mod, Mod 11 was introduced in 1996 and is a reinforced casing intended as a penetrator weapon. It is reputedly capable of penetrating at least 15 to 25 feet before detonating. All remaining MK 61 weapons have been upgraded to the standards of the Mod 3/4 bombs with the most sophisticated of the security devices, full fusing options and PBX-9502 insensitive high explosives in the primary. Not only is the full range of fusing options electronically available to the carrying aircraft but also the yields, the MK 61 being called the “dial-a-yield-bomb”. Yield options range from .3 kt to 360 kt with variations between Mods as to which yields can be selected. Known yields are .3, 1.5, 10, 45, 60, 80, 170 and 360 kt. The MK 61 is 11' 10” long and 13.33” in diameter. Weight varies by Mod between 755 lbs. and 1250 lbs. for the Mod 11 penetrator. Highly versatile, modular and very efficient, this bomb will undoubtedly remain in service for many years. Four existing variations of this weapon are to be modified into one. An important new feature is a new tail kit with controllable flaps. The new system would dramatically increase the bomb's precision. Aircraft that could carry the MK 61 were the A-4, A-6 and KA -6, A-6, A-7, F-4, F/A-18 and the AV-8B Harrier.

While the MK 83 megaton-range thermonuclear bomb is in the current US inventory, it is not a weapon currently used by the navy, and therefore the list of bombs used by the navy ends with the MK 61.

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Part 7: Anti Submarine Warfare Weapons

While the earliest years of the U.S. Navy's involvement with nuclear weapons focused on the fleet developing the immediate capability to deliver nuclear bombs from aircraft carriers, early planning also included future development of weapons for specific roles other than tactical (or strategic) strike missions. Programs evolved within the navy planning structure beginning in the late 1940s to provide nuclear weapons for the anti-submarine warfare (ASW) role, ship-borne AA missile defenses and ship or land attack missiles and then the final strategic role of submarines which developed as the last and largest nuclear weapons program in the navy and probably the world.

ASW was an obvious candidate for nuclear solutions because submarines were, even in the days before nuclear boats, very difficult to locate, pinpoint and sink compared to their surface sisters. WWII had seen great strides in conventional ASW tactics, pioneered in those early dark days of war by the Royal Navy and the Commonwealth navies working with them against the deadly U- boats. Later, with the U.S. Navy fully involved in war and the learning curve behind them, these international ASW specialists cleared the seas of the submarine threat in three oceans simultaneously. German advances in submarine technology came too late in the war to affect the ASW picture. Post-war, however, it was obvious that advances in ship propulsion and hull shapes were once again going to complicate the issue for those tasked with the sub hunter role. A nuclear weapon, by virtue of its huge kill range in comparison to the conventional ASW ordnance of the day and also its potentially more rapid delivery to the target, seemed to be an excellent, if expensive, way to resolve current ASW issues in case of a nuclear war.

Once again, submarines made the problem more difficult when the shift was made to nuclear powered submarines capable of very high speeds underwater, deeper diving depths and virtually unlimited range. Submarine attack capabilities were also enhanced by new weapons and sonars – very much improved torpedoes and far more sensitive sonar suites. Still, even with the advent of the nuclear submarine, a nuclear anti-submarine weapon had about the highest probability of a kill as any ASW weapon developed post-war. Of course they would never be employed in any but the direst of circumstances, so they supplemented the conventional ASW weapons cache rather than dominated it and ASW capabilities with conventional ordnance delivery systems proceeded apace.

(One should also note that these types of weapons – usually referred to as "ASW weapons" or “depth charges” – could as easily devastate a fleet of ships, surface ships being highly vulnerable to the intense underwater shock wave generated by a nuclear explosion, as clearly demonstrated during the Operations Crossroads Baker test. Ships not sunk outright by such a blast would have a high probability of sustaining crippling internal damage from the twisting and bending of major structural supports and plates. Considering the potential for intense radiation poisoning from any base surge to go with the damage, ships in this situation would probably be left in an intensely radioactive environment with no escape possible. This would be thoroughly depressing for ship's crews, to say the least.

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With that as background, this section covers the U.S. Navy's ASW weapons themselves, i.e., the delivery systems for the ASW-dedicated nuclear warhead as well as the warhead itself, including the MK 90 Betty depth charge, the MK 101 Lulu depth charge, the MK 45 Astor torpedo, the ASROC (RUR-5A), and the SUBROC (UUM-44A).

The MK 105 Hotpoint bomb, covered previously, was the first lay-down delivery bomb and had an additional role as a depth charge by virtue of being detonated by a delay-timer. This weapon, with its early MK 34 warhead will not be covered further here. Covered in the same section on bombs, The MK 57 bomb also had a primary role as a nuclear depth charge in addition to its roles as a tactical nuclear bomb, replacing the earlier MK 101 Lulu. Unlike the MK 105, the MK 57 was equipped with hydrostatic fusing as well as its other detonating options. It also had a parachute laydown/delay option and was the most versatile of all the ASW depth charges. The MK 57 was the last and best nuclear air-dropped ASW weapon in the navy's inventory, and could be carried by the majority of the navy's attack and patrol aircraft over the weapon's long life in the active inventory. The last MK 57 was retired in 1992.

MK 90 "BETTY" Depth Charge

Two years after the appearance of the MK 7 bomb, the navy fielded its first ASW nuclear depth charge, the MK 90 "Betty". The Betty was simply a MK 7 Mod 1 warhead married to a depth charge shaped "package", and included a parachute retardation option, an option that could be selected or by-passed for free fall. The MK 90 had hydrostatic fuses with a delay timer back-up. The Betty was 10' 2" long, 31.5" in diameter and weighed about 1243 lbs. The Betty was an excellent early example of adapting a nuclear warhead to more than one specialized function and drop-shape, but because the MK 90 used the early MK 7 warhead, it was somewhat limited by being a more maintenance-intensive weapon to prepare for use, requiring the nuclear capsule (stored separately) to be inserted in the weapon before loading out and having usual early problem of battery life for the electronic components, and "shelf life" of the weapon once prepped. This made the weapon slower to activate and deliver than would be desired in an optimal wartime situation, but was an acceptable limitation at the time the weapons were deployed with the navy's ASW forces, as it got a functioning weapon to the fleet at sea and on shore.

225 MK 90s were built beginning in 1955, and the last MK 90 was withdrawn from service in 1963. Wide variations in the yield of this weapon are found in the literature, with most stating something in the 5 – 10 kt range, but one authoritative source stated that the MK 90 had a yield of 32 kt (well within the MK 7s capabilities). 32 kt – about one and a half times the size of the Operation Crossroads Baker test – seems a bit massive for the intended purpose of sinking a submarine, but on the other hand, was admirably suited to the fleet destruction role, a role that was apparently one of the goals of the weapon designers. The MK 90 has always been "a depth charge" officially, but its other applications are obvious, the same applying in one degree or another to all the navy's nuclear ASW weapons.

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Naval aircraft capable of carrying the MK 90 were the A-1, P2V, P-3, P5M, S2F and the SH-3 helicopter.

MK 101 "LULU" Depth Charge

The MK 101 Lulu was the second of the navy's depth charges, and a considerable improvement over its MK 90 predecessor. The MK 101 utilized the outstanding W-34 "Python" boosted fission design as a warhead with a yield in the Lulu of around 10 – 15 kt. This greatly shortened the prep time for the weapon as the W-34 required minimal maintenance when deployed and had a readiness "shelf life" far more than sufficient to cover a combat tour. There was no parachute-retardation option with the MK 101. The MK 101 was deployed with the fleet from 1958 to 1971, slowly replaced by the multi-purpose MK 57 bomb. The MK 101 had a shape similar to an overgrown WWII Hedgehog, with a very heavy steel plate nose to improve the sink rate and was 10' 2" long, 31.5" in diameter and weighed about 1200 lbs. (of which only 320 lbs was the W-34 warhead). 2000 MK 101s were produced in five Mods.

Naval aircraft that could deliver the MK 101 were the AD, P2V, P3V, P5M, S2F and the SH-3 helicopter.

The MK 45 Astor Torpedo

The MK 45 torpedo was the only nuclear torpedo designed and deployed by the U.S Navy, and was specifically created to kill fast deep-diving nuclear submarines. The weapon grew out of the perceived need to counter the threat of the Soviet navy's massive build-up in submarines during the early 1950s and was based on the existing design for a new "Anti-Submarine Torpedo" with a conventional warhead already on the drawing boards and designated the MK 45. Warhead development for this weapon was requested in 1957, and quickly settled on the already-proven W-34 warhead used in the MK 101 Lulu depth bomb and the MK 105 Hotpoint laydown bomb/depth charge. Production of torpedoes mated to the MK 34 began in 1961, with delivery to the fleet beginning in 1963. The torpedo was used on both the last of the retrofitted "Guppy" diesel-electric boats and most of the later nuclear attack boats and boomers. (Nuclear-capable diesel boats could usually be identified by the unique triple housing of the PUFFS sonar system on the main deck.)

The MK 45 torpedo was 18' 9" long and 19" in diameter, weighing about 2680 lbs. Capable of 40 knots, the torpedo had a range of about 8 nautical miles. The weapon was wire-guided, which supposedly limited the torpedoes range somewhat, but more importantly required and active ping from the launching submarine to determine or update range and bearing data, an attack concept not in the least popular in the submarine force. The maximum range was no thrill either in the opinion of the men in the boats, who often gave the torpedo a PK number (probability of kill) of 2. Its destructive power (10 –15 kt) and extreme accuracy kept the weapon in the fleet as the primary nuclear ASW response aboard both SSNs and SSBNs. Deployed from 1961, the Astor was withdrawn from the fleet beginning in 1972. A total of 600 Astor torpedoes were built.

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The ASROC (RUR-5A)

The ASROC was developed to provide a stand-off attack capability for cruisers and destroyers and ASROC would become the first and only nuclear anti-submarine system deployed on these types of ships (as well as smaller frigates). The ASROC grew out of an earlier navy program called RAT (for Rocket-Assisted Torpedo) which suffered from poor accuracy, short range and limited payload capacity. In 1955 the project evolved into the ASROC program and shipboard evaluation of the rocket began in 1960 aboard the test vessel USS Norfolk, a specialized one-off ASW light cruiser and test vessel, with operational capability achieved the next year when four destroyers were the first to be equipped with the now well-known ASROC MK 16 "pepperbox" eight-cell launcher.

The warhead for the ASROC, the W-44, was not finally ready until late in 1960. The W-44 was quite similar to the primary used in the MK-43 thermonuclear bomb and measured 13.75" by 25.3", weighing some 170 lbs and with a yield of around 10 kt. (Over 12,000 ASROCs were built, but only 575 nuclear warheads were manufactured for them.)

The ASROC was a basic unguided ballistic rocket (thus the navy's "rocket" designation of RUR) weighing 1000 lbs and was 15' long with a diameter of 12.5". The solid propellant rocket gave the weapon maximum range of 7 miles. The ASROC had three Mods, the Mod 3 carried the conventional MK 44 homing torpedo, the Mod 4 had the MK 46 Mod 1 homing torpedo and the Mod 5 carried the W-44 nuclear depth bomb. The torpedoes were fitted with parachute packs for descent to target, while the nuclear depth bomb was strictly a free-fall weapon. Some 262 U.S. naval vessels were eventually equipped with the ASROC system either as the pepperbox launcher or from a modified Terrier missile launcher. Later ships used VLS for launching ASROCs, but this version has no nuclear capability. Foreign navies also fielded the ASROC, but only in conventional types.

The ASROC was one of the full-up nuclear weapons delivery systems to be tested when the USS Agerholm (DD-826) launched a nuclear ASROC as part of Operation Dominic, Shot Swordfish on 11 May 1962. The ship fired at a target raft at 4000 yards (2 nm) and the weapon detonated 4350 yards from the ship. As well as being a proof test, the shot was used to test the effects of a nuclear detonation on the ship's sonar and structures. As can be imagined, a nuclear detonation thoroughly messes up sonar reception for a time in the vicinity of the blast. One assumes that the Agerholm, shown stationary in the well-known photo of the test shot, got underway immediately after, as the ship would not want to have been anywhere near the base surge from the blast, which would have been intensely radioactive. Shot Swordfish was the last of five underwater nuclear tests conducted by the U.S.

While the conventional ASROC is still in use from the VLS on many ships, they are conventional torpedoes only; the last W-44 was withdrawn from the active fleet in 1989.

The SUBROC (UUM-44A)

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The SUBROC (SUBmarine ROCket) was a rocket-propelled nuclear depth bomb capable of being launched from submerged submarines from the standard 21" torpedo tube. SUBROC was a nuclear-only weapon. Development of SUBROC began in 1958 with a first test-launch (without warhead) made on 3 August 1959. The SUBROC was far more difficult to develop than the ASROC for several reasons, one of the main ones being it used a thermonuclear warhead and the others being the need for a specialized long-range sonar system to detect submarines out at a range of 40 miles and also a specialized fire-control system which could use the sonar data to program and prep the missile for launch. The weapon was an analog device and eventually only the Permit class of nuclear submarines would be fully equipped with SUBROC and its sonars and fire control equipment. The rocket itself went through a lengthy development process in order to work out the myriad problems of getting a rocket out of a torpedo tube, through the water and into the air, and then on to the target, problems that delayed getting SUBROC to the fleet until mid-1965. SUBROC was also another weapon that required and active sonar "ping" from the launching ship to lock in target bearing and range prior to launch. SSNs do not like to make active pings, for obvious reasons.

The SUBROC system all up was 21' long and 21" in diameter, weighing about 4000 lbs. Using 2-stage solid propellant rocket motors, maximum range was 25 – 30 miles at Mach 1+. Guidance was inertial. The W-55 warhead was 39.4" long and 13" in diameter, weighing 470 lbs. Yield was given as "1 – 5 kt" which seems very low for a thermonuclear warhead, particularly one based on the Operation Hardtack 1 Shot Olive test device which had a yield of 202 kt. It has also been stated that the missile had a secondary airburst option for the warhead, which implies a much higher yield as well. 285 W-55 warheads were manufactured. Submarines were credited with being able to carry 4 – 6 SUBROCs on board. By 1989 the last SUBROC nuclear warheads had been withdrawn from service.

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Part 8: Rockets and Missiles

This section covers the nuclear-capable rockets and missiles developed by the United States navy.

While the early development of nuclear weapons following the end of WWII focused on air-dropped bombs, all the US military services were also planning to marry nuclear weapons with missiles as fast as technology would allow. The development of the V-1 and V-2 by Germany late in WWII had laid the groundwork for what would become the missile programs of both the Soviet Union and the United States as soon as the end of the war allowed both nations to get their hands on the German missile technology and the scientists and engineers that went with it. It was probably fortunate that the United States seems to have acquired the best of the scientists and tecnicians, due primarily to the intense dislike these individuals had for being absorbed into the Soviet system.

While the V-1 "buzz bomb" created havoc and killed many people (almost all civilians, of course), it was more of a pilotless bomb than a smart missile, and because of its relatively low speed, low altitude and poor accuracy could be dealt with (barely) by the weapons available to the Allies at the time – fast aircraft and radar-controlled antiaircraft weapons. The V-2, however, was the weapon that scared the epaulettes off the military and the pants off the diplomats. Once launched, it was undetectable and unstoppable, a true "terror" weapon in that respect. Although it also had very poor accuracy, anyone with an engineering degree and a slide rule could figure out that it would not be hard to greatly improve the V-2's accuracy with minimal effort, to say nothing of increasing the range and payload.

Ignoring the Soviet efforts here, the US immediately began work to develop both the V-1 and V-2 into "Americanized" weapons following the close of the war. Although the nuclear bombs of this period were large and heavy, the continuing design work at Los Alamos had already made it clear that with more engineering and scientific development, weapon sizes would be greatly reduced within a few years, and could then be easily carried by a good rocket or missile to long ranges. The US navy first developed a version of the V-1 called "Loon" (LTV-N-1) and modified two Balao class submarines to carry this slightly more advanced version of the missile (with a pulse jet built by the Ford Motor Company and better guidance). Tests with the modified USS Cusk and Carbonero, that carried the Loon in a water-proof cylinder mounted behind the bridge, proofed the weapon and also made it obvious that it wouldn't be a prime candidate for a nuclear warhead, although basic design work on a nuclear warhead for this missile was begun at Los Alamos and then cancelled. Range, accuracy and speed were all problems with this weapon, in addition to simple reliability issues. The navy was also not enamored with carrying liquid fuels of any kind for missiles on board submarines for obvious reasons, although in the case of the Loon the fuel was not any different than the normal aircraft fuel carried aboard aircraft carriers. Probably the biggest drawback to the submarine-launched missile concept at the time was the fact that the submarine had to surface for the time-consuming process of breaking out the missile, loading it on its launch rails and then firing it – putting the launching

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submarine at great risk of detection by removing its greatest asset – stealth. The Loon was a short-lived program, being replaced by the two versions of the Regulus missile which is where the US navy's real nuclear missile program began. (The US navy tested a V-2 missile launch from the flight deck of the USS Coral Sea around this time as well, a one-time shot to prove it could be done, with no program behind it to make it a deployed weapon on any ship, and no nuclear warhead design for it in the pipeline, again due primarily to the liquid fuel problem and the enormous logistical requirements and time-intensive preparation of the missile for launch. It is also obvious that a liquid-fueled missile of that size stored aboard a carrier would represent a huge danger to the ship, nuclear warhead or not.)

Before the guided missiles came along in their first versions however, the navy did develop a tactical atomic rocket for launch by aircraft, and this section begins with that weapon.

The Bureau of Ordnance Atomic Rocket (BOAR)

The BOAR grew out of the expansion of American nuclear weapons into the "tactical" role following the Soviet's first nuclear test in 1949 – the Soviet test, enormously aided by espionage, had come much earlier than US intelligence sources had predicted, which put the American weapons development programs into high gear. While the US navy had methods of strategic strike with nuclear bombs, including a "penetration" weapon, they did not yet have a good method of delivering a tactical nuclear device (relatively low-yield) against ships at sea, since high-altitude bombing was probably out of the question due to the rapid development of fire control and fighter-direction radars; low level bombing at that time would not allow for the escape of the delivery aircraft, which is hard on pilot morale and airplanes to say the least.

The navy's solution revolved around advanced versions of the WWII "Bat" radio-controlled glide bomb (itself a spin-off of the German weapons of the same kind) which had taken a heavy toll on Japanese vessels at the end of the war while allowing the attacking aircraft to remain out of range of the air defense systems of the day. The Bat was similar in tactics and effect to the kamikaze, minus the idiocy of killing one of your own simply to hit a target. Combining this "stand-off" capability with a nuclear warhead provided the early solution to the problem of attacking fleets at sea with minimum warning and a higher degree of safety for the launching aircraft. In 1952 the navy's Bureau of Ordnance tasked the Naval Weapons Test Center at China Lake, California with developing the "30.5 inch Rocket, MK-1" which became known as the BOAR. (The weapon also was developed with a conventional warhead and was known as the "Bombardment Aircraft Rocket," – also "BOAR" in this configuration – thus the common confusion surrounding the acronym.) This weapon lacked the radio guidance of the Bat, but this type of guidance, necessary to put a small explosive package onto a small moving target, was not needed for a nuclear warhead aimed at a fleet of ships.

Designed for delivery using the low-altitude lofting technique that later became known as LABS, the development of the BOAR was relatively quick, with field testing in 1953, production beginning in 1955 and the first units in the fleet in early 1956. The BOAR was equipped with the MK-7 warhead with a yield of 20 kt. Weighing 2000 lbs. all up, the rocket was 15' 3" long and

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30.5" in diameter with small 4' 6" stabilizing fins. Using a 15,000 lb thrust double-base solid fuel rocket motor, the sub-sonic (480 mph) weapon had a range of about 7.5 miles from the launch point. Although intended as a short-life interim measure, the BOAR actually remained active in the US fleet until 1963, undergoing several upgrades intended to improve performance, particularly range, during that time. The BOAR had all the disadvantages associated with the MK-7 warhead, including prep time and shelf-life, but was quite adequate for its intended role. Delivery was primarily assigned to the AD (A-1) but it could also be carried by the A-3 and several of the early navy fighters, including the F2H Banshee. The last BOARs were removed from the fleet in 1963. Around 225 nuclear BOARs were built.

Regulus I (SSM-N-8, changed in 1963 to RIM-6) (and the Regulus II)

Design work on what would become both the navy's first nuclear-capable missile and the first submarine launched missile was initiated in October of 1945 via a contract with the Chance-Vought Aircraft Corporation (makers of the legendary F-8 Crusader fighter). The basic Regulus missile, looking like a small fighter minus a canopy, was first tested in 1948, with an operational missile ordered by the navy in May of 1950. The Regulus was developed from the preceding Loon missile program and was a considerable improvement over that early effort. The navy planned for it to be launched primarily from submarines, although some heavy cruisers and aircraft carriers would eventually also be Regulus-capable. As with the Loon, the launching submarine would have to surface, extract the missile from its hanger, and then prep the missile for launch from short launching rails, a dangerously time-consuming process. And the missile could not be prepped in very foul weather or sea conditions, a definite drawback in its eventual operating areas in the far north Pacific. (It should be noted that the Soviet's similar development, the P-5 Pyatyorka, known as the SS-N-3 Shaddock in NATO terminology, had a much more efficient launch system in which the missile tube also served as the launcher, although the submarine still had to surface to launch the weapon. This also made the missile more amenable to launch in foul weather. This missile served on 69 Soviet conventional and nuclear submarines – Whisky Twin Cylinders, Julietts, Whiskey Long Bins and Echo I and IIs.)

The Regulus was originally designed with a conventional 4000 lb high-explosive warhead in mind, but by 1949 the decision had been made to fit a nuclear warhead, and the Regulus only deployed in the nuclear configuration. Live tests of the full missile package, minus nuclear warhead, began in 1957 with a launch from the heavy cruiser Helena (CA-75) with guidance being passed from the Helena to two different submarines enroute to the target. The missile could use several different types of attack routes from treetop level to about 40,000 feet and would then dive onto the target.

The Regulus was first equipped with the Mk 5 warhead with yields from 10 to 45 kt. Later the missile was upgraded with the much more powerful Mk 27 thermonuclear warhead with a yield of 2 MT, a yield more appropriate to the intended targets such as Vladivostok. The Regulus 1 became operational in May of 1954 on board the submarine USS Tunny (SSG-282). Four heavy cruisers and eight Essex-class carriers also operated the Regulus, but the regular deterrent patrols with this weapon were all by submarines, two converted Balaos (Tunny and Barbero,

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SSG-317) two purpose-built Diesel boats (USS Growler and Grayback, SSG-574 and 577) and one nuclear submarine, the USS Halibut (SSGN-587).

The Regulus was the navy's first forward-deployed nuclear missile constantly maintained at sea in operational areas; between October of 1959 and July, 1964 one or two submarines with Regulus missiles were usually on patrol in the North Pacific. Apparently, throughout this period the missiles and warheads themselves were forward-deployed to a base on Chichi Jima in the Bonin group of islands south of Japan. Regulus missiles were removed from the Essex class carriers by 1956 with the advent of better tactical bombs and the aircraft to deliver them. The heavy cruisers carried Regulus for a few years longer.

228 nuclear-capable Regulus missiles were produced in all with the last delivered in late 1958. The Regulus was removed from service by July of 1964 and the navy would not have another cruise missile in the inventory until the advent of the Tomahawk in 1982. The Regulus was 34' 3.75" long and 4' 2" in diameter with a wingspan of 21'. Weighing 13,485 lbs. the missile was powered by an Allison J33 turbojet with 4600 lbs of thrust. Launch was aided by two Aerojet 2KS boosters with 16,500 lbs of thrust each. The Regulus had a range of about 575 miles at high subsonic speed. Although there are extensive records of Regulus tests of one kind or another launched from surface ships and submarines, I can find no record of any full-up nuclear test of a Regulus. Since the Regulus was around in the era of massive weapons testing, it is possible, but on the other hand, both Regulus warheads were originally bomb warheads that had been tested, so it may not have been necessary to test a nuclear Regulus. (There is a list of all nuclear tests directly related to various deployed weapons systems in the late Chuck Hansens's "Swords of Armageddon" CD.)

The Regulus II missile was an advanced and larger land-attack upgrade of the Regulus I that would have been supersonic (1320 mph – Mach 2) and with increased range and accuracy. Intended to carry the same W-27 2 MT warhead as the Regulus I, the missile would have been carried primarily by submarines as with the Regulus 1. The first Regulus II test flight took place in 1956 with the first submarine launch (from the USS Grayback) in 1958. The missile was intended to be fully operational in 1960, but the Regulus II program was cancelled by the Secretary of the Navy in December of 1958 so the funding could be applied to the much more important Polaris program. Submarines intended to carry the Regulus II retained the Regulus I until that weapon was retired.

(The nuclear powered USS Halibut, with its missile bays designed for either Regulus was later converted into the navy's first "bottom feeder" spy vessel with special equipment and a moon pool in the former missile bays for retrieving objects from the sea bottom and scanning the ocean floor for discarded Soviet tidbits such as missile re-entry vehicles. It was the Halibut that located the remains of the Soviet K-129 ballistic missile submarine in the Pacific northwest of Hawaii, initiating the CIA-sponsored effort to recover the submarine under Project Azorian using the purpose built Glomar Explorer.)

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Even before the cruise missile program that produced the Regulus, the US navy had initiated a large program called "Bumblebee" in late 1944 to develop ramjet-powered missiles suitable for the anti-aircraft role, a direct response to the kamikaze threat. Without going into the long development scenario that began at the Applied Physics Laboratory of John Hopkins University, the program eventually produced the long range ramjet Talos, the solid-fueled medium range Terrier and the short range Tartar missiles, all of which went through many teething troubles before reliable production versions could be carried aboard ship. Both the Talos and Terrier had a nuclear capability and both had a limited ship to surface capability. The other member of the “T” triad, the short-range Tartar, would eventually morph into the current Standard series of missiles used by the navy.

Talos Missile (SAM-N-6, later RIM-8)

Talos was the second product of the Bumblebee program, but there was a long period of developmental testing of the proposed ramjet engine before a real missile emerged from the program in 1950 with the first tests of a full-up Talos type missile. Intended to be a very long range missile, testing continued from 1950 to 1957 before a missile was developed that had the speed and range the navy required. The Talos entered service with the US navy starting in 1958 and because of its size was only carried on seven cruisers – three Galvestons (Cleveland class light cruiser conversions) three Albanys (Baltimore class heavy cruiser conversions) and the nuclear-powered Long Beach.

The Talos missile was 38' long and 28" in diameter with a 9' 2" wingspan and weighed 7800 lbs with its Mk 11 solid propellant booster. Prime propulsion was with a Bendix ramjet which gave the missile a speed of Mach 2.5 and at least a 70 mile range to 80,000', making it capable of intercepting aircraft before they could launch their anti-ship missiles. The Talos guidance system was beam-riding with semi-active terminal radar homing using the AN/SPG-49 target illuminators and tracking radars. The nuclear version carried the W-30 warhead with yields of .5 kt (Y1) and 5 kt (Y2). The warhead was 4' long and 22" in diameter weighing between 438-490 lbs depending on yield. Some 600 W-30s were produced for The Talos as well as for a tactical atomic demolition munition and the Talos nuclear version was available from 1959 to March of 1979 when the last active system was retired on the cruiser Long Beach. The W-30 warhead is reportedly the first to use the “zipper” type of initator, and external nuetron generator that replaced the older polonium/beryllium intiators in use since the Fat Man weapon was developed.

The Talos was a highly successful missile with long-range conventional warhead kills recorded during the Vietnam War and also was very successful in a modified version that had an anti-radar capability, reputedly shutting down the North Vietnamese radar system for a considerable period. Talos also had a limited surface to surface capability in the nuclear version. After the Talos system was retired, the remaining missiles went on to serve as high-speed targets under the designation MQM-8G Vandal, used mostly to test the various Standard missiles and the Aegis radar fire control system.

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Terrier Missile (Terrier BTN, later RIM 2D)

The Terrier was the medium range member of the "T" triad of missiles that emerged from the navy's Bumblebee program. Produce in several variants, the nuclear version was designated as the RIM-2D. Terrier missile installations were aboard 3 aircraft carriers (the USS Kitty Hawk and her two sisters, which did not carry the nuclear version) and 38 cruisers during the missiles lifetime. (Two other ships also carried a Terrier installation, the missile/gun test ship USS Mississippi and the destroyer USS Gyatt, neither of which were capable of handling the nuclear version of the missile.)

The nuclear Terrier was modified to provide a long-range tactical surface to surface capability in addition to carrying a nuclear warhead. This capability did not interfere with the missile's surface to air role. The Terrier entered service in 1956, but the nuclear version did not appear until 1958, with full operational capability in 1962. Nuclear Terriers were in service from then until 1989. The missile was 38' long with booster and 13" in diameter, weighing about 3000 lbs. The Terrier used both a solid propellant booster and sustainer motor, giving the missile Mach 3 speed and a range exceeding 20 miles with a capability of reaching 80,000' altitude. Like the Talos, the Terrier was a radar beam rider with semi-active terminal homing. The nuclear warhead developed for the Terrier was the W-45 Mod 1, also adapted with different Mods for a medium atomic demolition munition and for the Bullpup-B and Little John rocket. The warhead was 27" long and 11.75" in diameter and weighed 150 lbs. Yield was variable up to 15 kt, indicative of its alternate surface to surface role. About 750 warheads were produced specifically for the Terrier.

The Terrier's nuclear version remained in front line service until 1987 as it was the most effective missile of its type, being able to stop large waves of enemy aircraft and intercept anti-ship cruise missiles. The Terrier's successors, the Standard (SM) family of missiles derived from the earlier Tartar does not have a nuclear capability, although such a missile was requested by the navy as the SM-2(N). Developmental funding was provided for this missile, using the W-81 1kt warhead (a modified Mk 61 bomb primary) but the program was canceled in 1985. It has been reported that the W81 would have had advanced radiation capabilities. Additionally, the Bullpup missile in its Bullpup-B variant carried the W-45 warhead, but this version of the missile was only used by the US Air Force. Navy Bullpups were all conventional.

Tomahawk Cruise Missile (BGM-109)

The Tomahawk cruise missile in its conventional land attack and anti-ship version is currently active in the US navy on a variety of ships from destroyers to the recently-retired Iowa class battleships and is also now carried by the four modified Ohio class Trident submarines converted from SSBNs to SSGNs. The Ohio's can carry up to 154 Tomahawks. Nuclear attack submarines can carry Tomahawks in the torpedo bays and in the newer vertical-launch cells mounted in the ship's bow.

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A nuclear variant of the Tomahawk, designated BGM-109A was developed and deployed from 1987 to 1992 but, due to the various nuclear weapons treaties now in effect, these have been withdrawn from service, although some 300 nuclear-capable missiles are still stored at strategic weapons facilities in Bangor, Washington and Kings Bay, Georgia and the warheads remain available to date. The Tomahawk warhead was the W-80 Mod 0, a modification of the B-61 bomb warhead with yields between 5 and 150 kt. This weapon uses specially-designed plutonium warhead components designed to lower intrinsic radiation levels for personnel protection aboard submarines – a safety feature that it has been reported the SUBROC did not have. The warhead was 31" long and 11.75" in diameter and weighed about 290 lbs. Around 1850 warheads were produced.

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Part 9: Ballistic Missiles

The US Navy was quick to notice the potential for marrying missile technology and nuclear warheads with submarines; initial planning for such weapons systems was underway by 1946 – the obvious advantage of a "stealthy" delivery vehicle capable of getting close to enemy territory undetected before launching nuclear weapons was not lost on the navy's planners. Focused at first on the easiest attainable goal, the "cruise missile," the eventual development of far more sophisticated ballistic missiles remained only on the drawing boards during most of this period, due to the high level of technical difficulties involved in getting a reliable ballistic missile into a small submarine frame with minimal danger to the launching submarine. Technical and scientific advances were needed before this program could come to fruition. Even the concept of placing these missiles in larger surface ships faced many engineering difficulties.

The concept of marrying a ballistic missile with a submarine was originally based on the plans of the German navy to develop a submersible "barge" capable of carrying V-2s under tow by a submarine. This would have been an extremely complex situation, but at least would have separated the submarine from the dangerous liquid-fueled rockets themselves. The US pursued similar programs on the drawing board, but nothing came of it while the cruise missile program was being developed, first with the "Loon" version of the German V-1; 351 Army-produced JB-2 versions being purchased by the navy and designated as the LTV-N-2 for deployment on two specially modified fleet submarines, the USS Cusk and Carbonero. Cusk fired the first Loon missile in February of 1947 and the missile age began for the US submarine force (with of course, a tip of the hat to the WWII exploits of the USS Barb under her innovative captain, Commander Eugene Fluckey, who conducted shore bombardments of Japanese coastal towns using a 5" unguided rocket and launching rails modified from those used in various landing craft).

The Loon was carried in a two-up pressure-proof cylindrical hanger mounted abaft the submarine's sail. The submarines were equipped with a 50' launching rail and all the needed fuel facilities and checkout/launch equipment. The Loon's main drawback for operational submarines was the necessity for the submarine to remain on the surface while the missile was removed from its container, set up on the launching rails, fueled and prepped for launch. Additionally, the missile was controlled by command radio guidance, which required the launching submarine to track the missile and provide guidance (which could be passed off to another submarine) while submerged at periscope depth with a radar mast deployed. Both of these factors greatly reduced the submarine's ability to remain undetected. The Loon had an effective range of about 135 miles, and was never deployed with a nuclear warhead. Design work on a warhead for the Loon was begun, but cancelled with the advent of the more advanced Regulus missile.

Despite its drawbacks, the Loon was capable of demonstrating that missile-equipped submarines posed a real threat both to land and sea targets. During fleet exercises in 1948, three Loon missiles were launched at an "enemy" task force. None of the missiles were shot down even though the task force was aware missiles would be launched, and were also aware

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of the general location of the launching submarines. With the potential for the Loon to have been carrying a nuclear warhead, the lesson was obvious.

The Regulus program developed a much better cruise missile that did carry nuclear warheads (both nuclear and thermonuclear – see the previous section on guided missiles) which was carried on the modified fleet submarines USS Tunny and Barbero, as well as the purpose-built USS Grayback and Growler and the nuclear USS Halibut. Regulus also required the launching submarine to be on the surface, and then at periscope depth to provide tracking and command guidance to the missile (which, like Loon, could be passed off to other submarines – while only the five submarines carried Regulus, many fleet boats carried the necessary command guidance and tracking equipment needed to assume control of a Regulus and guide the missile to a target.)

During this period, the navy's interest in developing ballistic missiles for submarines lagged, the main reason for this being the necessity at the time for any such missile to be liquid-fueled, something the navy opposed tooth and nail. This was especially the case after the navy conducted special tests at White Sands Missile Range in 1948 to test the "missile accident" scenario in Operation Pushover. The operation was simply designed to see what would happen if a liquid-fueled missile were to collapse or topple over during launch in a shipboard environment. The damage caused by the fully-fueled V-2 test missile was devastating, showing clearly that no submarine could survive that kind of accident. With this ammunition in hand, the navy resisted any and all attempts to base ballistic missiles at sea, although they were more or less forced to cooperate with the US Army's Jupiter program with an eye to developing a submarine that would carry three liquid-fueled Jupiters in and extended sail launch capsule similar to the Soviet's K-129 boats. This was more the result of this program being the only one available at the time that would produce a missile small enough to be contained within a submarine rather than any expectation on the part of the navy that this would actually occur at some point.

Fortunately for the navy, several factors came together that would allow for the rapid development and deployment of Intermediate Range Ballistic Missiles (IRBMs) from a nuclear submarine (which would be designated as "SLBMs" for Submarine-Launched Ballistic Missile regardless of the missile's range). The program would eventually evolve to where the submarines would carry the long range "big brother" version, the Trident II D-5 Intercontinental Ballistic Missile (ICBM) now currently the only ballistic missile in the navy's inventory.

The prime scientific and engineering advancement that allowed the navy to seriously consider ballistic missiles for submarines was the development of large, powerful and very reliable solid-fuel rocket motors and sustainers, followed by the development of inertial guidance systems for missiles that did not depend on radio transmissions and radar tracking during the course of the missile's flight. Additionally, the nuclear weapons labs were on the verge of producing high-yield, low-weight thermonuclear warheads ideal for mounting on a missile. With these developments coming out of the labs, the navy was quick to drop out of the Jupiter program and pursue the goal of a submarine-launched ballistic missile of its own design. The driving

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force behind this development was the appointment of Admiral Arliegh Burke as the Chief of Naval Operations. A brilliant leader, administrator and war-fighter, Admiral Burke was without a doubt the most competent Admiral since Nimitz, and he was as committed to seeing the ballistic missile program become a major navy contribution to national defense as he was in seeing the navy into the nuclear powered age. One of his first steps was to put a stop to the intra-service bickering between the navy's Bureau of Aeronautics and Bureau of Ordnance over who would control ballistic missile development – he took the responsibility away from both bureaucracies by placing the program entirely within a "Special Projects Office" answerable only to the CNO and secretary of the navy. Admiral Burke assigned Rear Admiral W.F. Rayborn to head this office. Rayborn was a genius when it came to getting the job done, and with the weight of the CNO behind him, was able to put a nuclear submarine to sea on patrol with nuclear-tipped ballistic missiles by 1960, at first the relatively short-ranged Polaris which would be followed by the ever more capable missiles in the Poseidon and Trident programs.

Four nuclear submarine classes would eventually be produced to carry ballistic missiles, beginning with the George Washington class, the first of which completed in December of 1959. The George Washington fired its first missile in July of 1960 and departed on the first deterrent patrol on 15 November 1960. The early SSBNs were built by modifying and existing Skipjack class nuclear boat with a 130' center section added to hold the 16 missile tubes and the launch and control equipment. Later submarines were purpose-built to this design. The deterrent patrols of SSBNs continue to this day and now represent a major portion of the United States' remaining nuclear capability.

Briefly, the four ballistic missile submarine classes were:

George Washington Ethan Allan Lafayette* Ohio** (SSBN-598) (SSBN-608) (SSBN-616) (SSBN-726) (5 ships) (5 ships) (31 ships) (18 ships)

Length: 381' 8" 410' 5" 425' 560'Beam: 33' 33' 33' 42'Draft: 26' 8" 27' 6" 27' 10" 36' 3"Displ. (s) 5959 tons 6946 tons 7325 tons 16,764 tonsDispl. (sub.) 6709 tons 7884 tons 8251 tons 18,750 tonsSpd. (s) 16 kts 16 kts 16 kts 18 lktsSpd. (sub.) 22 kts 21 kts 21 kts 25 ktsMissiles 16 16 16 24

(* The Lafayettes were divided by Jane's Fighting Ships into sub-classes depending on their missile upgrades over time.)** The first four Ohio class SSBNs have been converted to SSGNs; the tubes for the Trident missiles have been modified to carry multiple-round Tomahawk missile VLS canisters and also special vehicles and equipment for special forces (SEAL) operations. These modified boats can carry up to 154 Tomahawks.

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The six ballistic missiles developed by the US Navy and carried on deterrent patrols were the Polaris A-1, A-2 and A-3 (UGM-27), the Poseidon C-3 (UGM-73A), the Trident I C-4 (UGM-96A) and Trident II D-5 (UGM-133A).

Polaris A-1

The Polaris A-1 was the first in the submarine-launched ballistic missile series and the world's first deployed long-range missile with solid-propellant rocket motors. Developed by Lockheed (as were all US-made SLBMs), the Polaris featured a SINS-based (Ship's Inertial Navigation System) guidance program and the missile was developed for undersea launch, which provided far more safety for the launching submarine. The developmental program for the Polaris was relatively quick and surprisingly trouble-free in comparison to some other programs. First flight-tested from Cape Canaveral on 20 April 1959, sea-going tests were conducted from the USS Observation Island on 27 August of the same year. By 20 July of the following year, the USS George Washington successfully launched two Polaris A-1s to a range of about 1150 miles. On 15 November 1960, the George Washington departed on her first patrol with 16 armed missiles on board.

On 6 May 1962, during Operation Frigate Bird, the USS Ethan Allan launched a Polaris A-1 from near Christmas Island to Bikini Atoll where the nuclear warhead detonated, the only fully live test of a submarine launched ballistic missile ever conducted. The Polaris A-1 was operational with the US navy from 15 November 1960 to 14 October 1965 when the last submarine carrying the missile returned to port (the USS Abraham Lincoln).

Weight: 28,000 lbsLength: 28'Diameter: 4' 6"Propellant: 2-stage solid-fuel rocket motorsRange: 1380 nmWarhead: 1 W-47/ Y1. The W-47 was 47" long, 18" in diameter and weighed between 717-733 lbs depending on yield (Y1 = 600 kt; Y2 = 1.2 MT, only the Y1 was installed on the Polaris A-1). About 1360 W-47s were produced, with around 300 in service at any one time.

Polaris A-2

The navy's original intention in developing the Polaris missile was to have one that would have a range of around 1500 nm, which had not been achieved in the initial Polaris A-1 deployment. The upgraded A-2 Polaris addressed this problem and had a range of around 1700 miles in addition to being an improved missile overall with a new lightweight fiberglass casing instead of thin-gauge steel. Testing of this missile began in 1960 with the first deployment of A-2s at sea beginning in June of 1962. Only five Ethan Allan class and 8 Lafayette class boats carried the A-2 Polaris, which was replaced in the inventory quicker than expected due to the accelerated development of the A-3 version of Polaris mandated by President Kennedy. The A-2 Polaris was operational with the fleet from June 1962 to about November of 1964.

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Weight: 32,500 lbs.Length: 31'Diameter: 4' 6"Propellant: 2-stage solid-fuel rocket motors.Range: 1730 nmWarhead: 1 W-47/Y2, 1.2 MT. (See above for dimensions.)

Polaris A-3

The Polaris A-3 was the last of the Polaris family, and was developed in response to the rapid advances being made in missile technology in the early 1960s, advances that would not be easily retrofitted to the existing Polaris A-1 or -2 missiles. The A-3 version of Polaris had a range of 2880 nm, exceeding that of the Air Force Thor ICBM. This increase in range was due primarily to re-designed missile casings using fiberglass instead of steel and to developing a new lighter-weight guidance package in addition to the other weight-saving improvements generated for this missile. The Polaris A-3 was the navy's first multiple-warhead weapon, carrying three W-58 warheads in a MK 2 Multiple Re-entry Vehicle (MRV). This allowed a weapon to "shotgun" a soft target which overcame problems of accuracy and also made it very difficult to intercept incoming warheads – an ABM missile would only be able to intercept one warhead target. With this missile, the Polaris equipped submarines made a significant jump in delivery capability from 16 warheads to 48. The three-warhead system also allowed for creating damage on a scale equivalent to the megaton warhead on the Thor Missile using smaller and less powerful warheads in a bracketing pattern – being the recipient of the sextuple shock waves from three 200 kt warheads detonating simultaneously plus the usual heat and radiation would have been just as bad if not worse than any low-megaton detonation.

The Polaris A-3 was fitted to 18 US Submarines – 5 George Washingtons, 5 Ethan Allans and 8 Lafayette class. Additionally, the Polaris A-3 was deployed on 4 Resolution class British ballistic missile submarines. (These A-3s were produced in America and were then mated to a British-developed nuclear warhead.) Polaris A-3s were active with the US navy from 1964 to 1981 and in the Royal Navy until May of 1996.

Weight: 35,700 lbs.Length: 32'Diameter: 4' 6"Propellant: 2-stage solid fuel rocket motorsRange: 2880 nmWarhead: 3 MRV W-58, 200kt. The W-58 warhead was 15.6" in diameter and about 40" long, weighing about 257 lbs. 1400 warheads were produced for the Polaris program.

Poseidon C-3

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The Poseidon successor to the Polaris program was a much larger missile than any of the Polaris versions and was also the first strategic missile to carry Multiple Independently Targeted Re-entry Vehicles (MIRV). The larger diameter of the C-3 was possible because it was found that the existing Polaris missile tubes would function safely with the original liners removed – the original very severe shock-mitigation requirements imposed in the early days of the Polaris program could be safely reduced. Up to 14 warheads could be fitted to the Poseidon missile, but normal deployment was 10 warheads per missile in order to maintain the range of the A-3. (Decoys could also be included in the warhead delivery vehicles.) The fitting of the MIRV package to this missile meant that each ballistic missile submarine fitted with Poseidon carried 160 warheads that could be delivered over a very large attack "footprint" and with much greater accuracy, the Circular Error Probability (CEP) being around 1500 ft. (With all 32 Lafayette class submarines equipped with Poseidon, this meant the navy had 4560 warheads available with this system alone, although not all would be at sea at the same time.) Poseidon testing began in August of 1968 and by March of 1971 Poseidon began deterrent patrols. The Poseidon missile was back-fitted to all 31 of the Lafayette class submarines. The 10 earlier SSBNs were not modified for the Poseidon.

The Poseidon missile was unfortunately beset with some serious flaws that became apparent in 1972 after several operational suitability tests had resulted in failed launches. According to The U.S. Nuclear Arsenal, p. 44, these failures were due to "…quality control problems in its small electronic parts, poor gimbal assemblies, a faulty firing unit and flaws in the submarine/missile connecting flexible cables." A program was put in place to rectify these problems and retrofit the existing Poseidons in the fleet as rapidly as possible. The last improved Poseidon re-entered the fleet in 1978.

The navy was also not very happy with the range of the Poseidon – originally planned to be around 4330 nm, the missile ended up with the same range as the preceding Polaris A-3 because of the heavier warhead package. This made the launching submarine more vulnerable to anti-submarine activities due to the necessity of being closer to the target during launch. This problem was addressed only by the development of the follow-on Trident missiles.

The last Poseidon was withdrawn from fleet service in October of 1991.

Weight: 64,000 lbsLength: 34'Diameter: 6' 2"Propellant: 2-stage solid fuel rocket motorsRange: 2880 nmWarhead: 10 (normal) to 14 367 lb. W-68 warheads of 50 kt yield each. (Accurate dimensions for this warhead have never been publically announced.) About 5250 warheads were built, and 3200 underwent upgrading to replace deteriorating explosives. This was the largest production run of a nuclear warhead in the US weapons program.

Trident I C-4

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The Trident program evolved out of the navy's perceived need for much better range for the submarine-launched ballistic missiles which would greatly increase the survival potential of the nuclear ballistic missile subs in a wartime scenario. Based on the Department of Defense STRAT-X study of the late 1960s, the Trident program was initially for developing a missile with a 6000 nm range, but this proved unrealistic with existing technology and submarines, so the navy instead went with a two-stage program with the interim Trident C-4 attaining a 4600 nm range while development continued on the much-advanced Trident D-5 which was expected to have a 6000 nm range. Trident missiles were back-fitted to 12 of the existing ballistic missile submarines and to the first eight of the much larger Ohio class submarines. The C-4 was also MIRV-equipped, with eight independently targeted reentry vehicles. First test flown in March of 1974 the missile became active with the fleet in October of 1979. The last Trident I C-4 was withdrawn from service in December of 2003.

Weight: 73,000 lbs.Length: 34'Diameter: 6' 2"Propellant: 3-stage solid fuel rocket motors.Range: 4600 nmWarhead: 8 MIRV W-76 warheads, 100kt each. Dimensions for this 212 lb warhead have not been released. About 3000 warheads were manufactured for the Trident C-4 missile.

Trident II D-5

Last of the submarine launched ballistic missiles, and the only one still in service, the Trident D-5 was intended as the very long range version of this family of missiles. Due to an increased warhead package, the D-5 as deployed did not achieve the planned 6000 nm range, the actual range being similar to the Trident C-4 although the missile does have much increased accuracy. The Trident D-5 was intended to carry the W-88 warhead, but the production of this warhead was cancelled in 1992 after serious safety concerns surfaced at the plant manufacturing the plutonium pits for the weapon. These problems resulted in the permanent closure of the Rocky Flats facility near Denver, Colorado, and the Trident D-5 was then equipped with the same W-76 warhead of the earlier Trident C-4. As a result, there are two warhead "packages" available for the D-5, a MK 5 reentry vehicle carrying the W-88 warhead and the MK 4 reentry vehicle carrying the W-76 warhead. Accuracy of the D-5 is legendary, with a CEP from 4600 nm away of about 500 ft. The Trident D-5 became operational in March of 1990 and currently equips all the Ohio class ballistic missile submarines.

The Trident D-5 is also deployed on the Royal Navy's ballistic missiles submarines, beginning with HMS Vanguard's first patrol in 1994.

The D-5 was first tested in January of 1987 and attained operational capability with the fleet in March of 1990. The D-5 is the last nuclear weapon constantly deployed by the US Navy.

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Weight: 130,000 lbs.Length: 44'Diameter: 6' 11"Propulsion: 3-stage solid fuel rocket motors.Range: 4600 nmWarhead: 8 MIRV W-76 (see the entry for the Trident C-4) or 8 MIRV W-88 warheads of 475 kt each. The W-88 is 68.9" long and 21.8" in diameter, weighing about 800 lbs. About 400 W-88s were manufactured before production ceased.

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