Nuclear Torpedoes

The threat the large Soviet submarine force poses de­mands that U. S. ASW forces have a very favorable ex­change ratio or we will simply run out of ASW platforms and weapons. This threat is especially serious for nuclear- propelled attack submarines (SSNs); assuming the U. S. Navy reaches its current goal of 100 SSNs, the ratio of Soviet submarine targets to U. S. SSNs will be about four to one.

The Soviet submarine force consists of a large number of classes with varying characteristics and, hence, varying capabilities and vulnerabilities. Further, continued mul­tiple-class construction—with possibly seven classes cur­rently in production—permits the Soviets simultaneously to employ and evaluate a variety of features that could

 

 

affect U. S. ASW weapon effectiveness.

These classes include the Typhoon and Delta IV nu­clear-powered fleet ballistic missile submarines (SSBNs); the Oscar nuclear-powered guided missile submarines (SSGNs); the Sierra, Mike, and Akula SSNs; and Kilo conventionally powered attack submarines. The Soviets have begun a major conversion program for Yankee-class SSBNs for possible use as attack submarines (SSNs/ SSGNs). In addition, during the past few years, they have produced several one-of-a-kind submarines, such as the Uniform, Lima, and the small X-ray nuclear research sub­mersible (like the U. S. Navy’s NR-1), all of which con­tribute to the Soviet “learning curve.”

There is no reason to anticipate a reduction in the size of the Soviet submarine force, its rate of modernization, or the large number of classes. Five Soviet yards are now engaged in submarine construction. The Severodvinsk yard on the Arctic coast has significantly greater subma­rine construction capacity than the combined capacities of the two current U. S. submarine building yards at Groton, Connecticut, and Newport News, Virginia.

Several features of Soviet submarine design and con­struction tend to mitigate the effectiveness of U. S. ASW weapons. These features include the following:

• The Alfa, Mike, and possibly other SSN designs use titanium, which increases resistance to weapons damage and significantly increases operational depth.
• Multiple compartments in Soviet submarines may re­quire that ASW weapons inflict damage on more than one compartment to assure ship kill. While the loss of a single compartment may cause a ship kill and probably mission kill, this cannot be assured for all current Soviet subma­rine classes. For example, would losing a single compart­ment so disable a Typhoon SSBN that she could no longer fire her missiles?
• Almost all Soviet submarines appear to have double hulls (i.e., an external hull around the pressure hull that provides hydrodynamic shaping, space for external equip­ment, reserve buoyancy, and “standoff” distance against attacking weapons). This standoff distance significantly reduces the effectiveness of both heavy and lightweight torpedoes, especially the latter. This distance is approxi­mately one meter for most Soviet submarines; some sources report that it is about three meters (amidships) in the Oscar-class SSGN. (The Oscar-class SSGN has 24 SS-N-19 antiship missiles in tubes, mounted 45° to the vertical, external to the pressure hull, 12 per side. These missile tubes are fabricated of high-tensile steel. Thus, they, in effect, form an “armor belt” along the sides of the Oscar, enhancing ship survivability against a hit in that location.)
• Soviet submarines have a relatively large reserve buoy­

ancy that also enhances survivability. Compared to a U. • submarine’s nominal reserve buoyancy of approximate y 10%, the reserve buoyancy of most Soviet submarines is on the order of 30% or more and is still greater for the Typhoon-class SSBN.

► Soviet submarines have several defensive features, bot passive and active. These are believed to include acoustic jamming and decoy devices, as well as anechoic coatings on the external hull, to reduce the effectiveness of U. ASW torpedo guidance.¹          .

The Soviets are reducing their traditional vulnerability of self-generated noise in their newer classes of subma­rines. Most classes of Soviet nuclear submarines currently in operation exhibit acoustic signatures characterized by numerous sonic signals produced by on-board machinery- The strongest of the low-frequency noise levels from these submarines at slow speeds (i.e., less than ten knots) show a modest reduction from one design generation to the next. All future classes are expected to achieve the noise levels of the current USS Los Angeles (SSN-688) class by 1990, and sometime in the 1990s U. S. and Soviet submarine noise levels could converge. Recently retired Chief °* Naval Operations Admiral James Watkins, articulated this trend when he made the following observation:

“When my first command, USS Snook, was launched |1960], we were infinitely ahead of the Soviets in nu­clear submarine technology. Later, about ten years ago, we were about ten years ahead of them. Today, wc are only about five-to-eight years ahead of them and they are still in relentless pursuit.”²

The Soviets are rapidly closing the qualitative gap. Dur­ing the past decade, the Soviets have introduced about l- new submarine designs—some for series production, and some one or two of a kind for research or special purposes. These new designs move the Soviets forward on the learn­ing curve and provide a probable convergence of the rela­tive effectiveness of U. S. and Soviet submarines, nil other factors being equal.

Soviet high-performance submarines can also reduce

the effectiveness of NATO ASW weapons by the subma­rines’ ability to outrun, outdive, or outmaneuver a tor­pedo. The Soviets have traditionally emphasized high ^sPeed in their nuclear submarines. The use of high-power Propulsion systems, such as the liquid-metal reactor plant ui the Alfa SSN and possibly other submarines, is provid­ing very high speeds (e.g., 43 knots, with the promise of speeds of 50 knots possible by about 1990). Even existing SSN speeds are significantly faster than the current U. S. Los Angeles-class SSN and even the planned Seawolf (SSN-21) class. The Soviet speed advantage can allow submarines literally to outrun U. S. torpedoes in certain scenarios.

In addition to faster speeds, Soviet nuclear submarines ^can dive to greater depths than contemporary U. S. sub­marines. The Alfa’s titanium hull provides a crush depth °f more than 1,000 meters. Future hulls are expected to be survivable to even greater depths. This depth is signifi-

cantly deeper than current U. S. submarines can operate.

This speed-depth combination provides Soviet subma­rines with the ability to make evasive maneuvers. Other features, such as the Alfa’s highly automated bow planes and possibly the secondary propulsion systems in the Alfa and Victor classes, also demonstrate Soviet emphasis on maneuverability. (These secondary systems are readily evident in drawings and photos, with two small propellers mounted on the horizontal stem-plane surfaces.)³

The Soviets are expanding submarine operations in the under-ice and marginal-ice environment. Evidence indi­cates that the Typhoon-class and probably the Delta IV SSBNs were designed specifically for under-ice opera­

tions.⁴ These environments adversely affect U. S. subma­rine sensor and weapon effectiveness, especially against Soviet submarines pressed up against the bottom of the icepack. In this condition, known as an “ice pick,” the target submarine produces no Doppler effect and is diffi­cult to distinguish from ice “keels” (downward icepack projections). Further, the ice conditions obviously inhibit the launch and reentry of the U. S. submarine rocket (SUBROC) and the planned Sea Lance ASW standoff weapon (ASWSOW), the only U. S. submarine-launched ASW weapons with nuclear warheads.

Some portions of the Arctic and several other ocean areas of importance to Soviet operations are relatively shallow, with depths of less than 180 meters. Shallow- water conditions also reduce U. S. submarine sensor and weapon effectiveness, especially that of towed arrays.

The Soviets have developed and deployed a variety of submarine weapons with different performance character­istics, launch modes, and warheads. This mix of weapons— especially the probable large load-out of nuclear torpedoes and nuclear standoff ASW missiles—can affect U. S. sub­marine tactics and operations for ASW missions. In addi­tion, the Soviets are developing submarine-launched air defense weapons which could add another dimension to their counter-ASW capabilities. All of these aspects have made the Soviet submarine a difficult ASW target.

ASW torpedoes’ advantages and weaknesses can be considered in the context of the following three generic functions:

• Maneuvering-homing weapon launched from subma­rines—heavy torpedo (Mk-48 ADCAP)
• Maneuvering-homing weapon launched from surface ships or aircraft—light torpedo (Mk-46, Mk-50)
• Maneuvering-homing weapon for a standoff delivery system, such as ballistic or aerodynamic missiles launched from submarines, surface ships, or aircraft—light torpedo (ASROC with a Mk-46 or Mk-50 payload)

Two other ways to kill a submarine are forms of depth bombs:

• Patterns of numerous charges (i.e., depth charges or hedgehogs), as the Soviet RBU series of ASW rockets and British Mk-10 mortar (Limbo)
• Nuclear weapons (i.e., ASROC [W44], SUBROC [W55], B57 depth charge, ASWSOW nuclear depth bomb [NDB], Soviet SS-N-15, and British WE177)

The U. S. Navy’s heavy torpedo, the Mk-48, consti­tutes U. S. submarines’ principal and, in most instances, only ASW armament. (Only about 20 U. S. SSNs are believed currently to have a SUBROC capability.)

The torpedo is a relatively short-range weapon. Never­theless, a homing torpedo has considerable “dead time” between its launch and its target acquisition when attack­ing a fast, maneuverable target. If the torpedo is launched at long range, an alerted target can move outside the reach of a homing torpedo’s sensor range as the torpedo begins its search maneuver.

Wire guidance helps solve the dead time problem by correcting the torpedo’s course as it runs, but it is subject to the limits of the launch platform’s sensors. An example is the Mk-48 torpedo’s wire guidance and acoustic horn-

kiloton yield for close-in shots.                                           ^ _nU_

At long ranges, sensor accuracy is much lower clear warhead raises target kill probabilities, but a ^          ^

ar wa

head, the accuracies of these airborne delivery system^

war

are

while

ing. SSN commanders say that under good conditions they can detect targets at greater ranges than the range at which a fire control solution is usually available for launching torpedoes. Commanders prefer to fire still closer to their targets for a high probability of a hit before the target can initiate a counterattack. At shorter ranges, the fire control solution is better, the probability of the target evading the torpedo is lower, and a counterattack cannot be launched unless the target successfully evades the approaching tor­pedo.

The Mk-48, fitted with a conventional high-explosive warhead, was introduced in 1972 as a replacement for the Mk-37 high explosive torpedo and for the Mk-45 ASTOR (antisubmarine torpedo) with a nuclear warhead. (One U. S. diesel submarine, the USS Darter [SS-576], still carries the Mk-37 torpedo.) In 1977, a Mod-3 version of the Mk-48, with a two-way telecommunications link for the torpedo’s wire guidance, was introduced. The tele­communications system updates the fire control solution by transmitting torpedo and target data from the torpedo to the submarine’s fire control system. This reduces dead time and allows the Mk-48 Mod-3 to engage targets with higher speeds than the Mod-1 can without the necessity of increasing the torpedo’s speed. As a rule of thumb, how­ever, a homing torpedo’s speed should be about 1.33 times that of the target’s speed. The Mod-4 program was recently completed to meet the challenge of the Alfa-class high-performance Soviet SSN. The ADCAP program will bring the next package of improvements to the Mk-48, intended to counter the next generation of quieter Soviet submarines. It should be in the fleet later this year.

The lack of any mature, nonacoustic detection technol­ogy means that acoustic sensors will continue to be the primary means of detecting, tracking, and targeting sub­marines. As quieter Soviet submarines enter service, they will become harder for Western ASW forces to find. This trend, coupled with poor acoustic environments in many specific regions, could reduce ASW submarines’ firing range to less than 10,000 yards.⁵ In this situation, an ASW standoff weapon would not have adequate targeting infor­mation to exploit its greater range. Thus, the torpedo will tend to be the dominant weapon for undersea platforms that are engaging quiet undersea targets in poor acoustic conditions.

The high-explosive warhead for the Mk-48 torpedo may be adequate, even against newer Soviet submarines which have considerable separation between their pressure and outer hulls. However, qualified analysts tend to be pessi­mistic in their long-term assessment of this adequacy.

At short firing ranges, a nuclear torpedo could present a hazard to the launching submarine, which was one reason the Mk-45 ASTOR—with a yield in the range of a few

kilotons—was withdrawn from service and replace the Mk-48. It was the first U. S. nuclear weapon ⁰^ withdrawn from the stockpile in favor of a conventio weapon. (Analysts used to quip that the Mk-45 ^nuC ASTOR had a kill probability of 2.0—against^{its tar}^_r. and the U. S. launching submarine.) Today s nuclcat ^ pedo can be made with several yields, including a or aerodynamic missile is a better type of delivery than a torpedo because it is faster. With a nuclear sufficient and are not affected by countermeasures, they do not have the long dead time of a torpedo.

Nevertheless, an insertable nuclear component war for the Mk-48 would provide high, single-shot ettec ^ ness against high-value, time-urgent targets, such ^ phoon SSBNs and Oscar SSGNs. It would also ad ■^e^ difficult problem of attacking targets under Arc ¹  ^

It’s difficult to tell whether this submarine’s crew is load­ing or unloading this SUBROC. But there’s no doubt that this weapon is on the way out, leaving the U. S. Navy without a nuclear ASW weapon until the ASW standoff weapon arrives.

j^^{re a} standoff weapon cannot be used, stud  ^a J°*^nt nuclear weapons design laboratory

Mk ^„^exam*^ned the convertible warhead concept for the 'ns th ^torP^e^°- This study showed the feasibility of giv- con ^{6 tor}P^e<^° ^{a nuc}l^enr capability while maintaining a in _tL^ent'^ona* capability in the same warhead. The warhead mat ii ^conventi°ⁿal mode has a void from which approxi- 103⁶ ^ ^ Pounds of the estimated 650 pounds of PBXN- could be removed to accommodate the insertable nu- ^a^ component.

bilit ^{6 C}°^nvert'^'^{e a}PP^roach would increase load-out flexi- _a t ^{y an(}i provide improved dual capability. For example, ^and°l ^ⁿ8eles-class SSN with 15 conventional torpedoes con *^{Ve nuc}^^ear weapons can use only 15 weapons in a If th ^eat'^onal conflict and only five in a nuclear exchange, ble ^{6 oac}T°^ut were ten conventional and ten with inserta- _ava?^U^^lear component warheads, 20 torpedoes would be a le for a conventional conflict as opposed to up to ^audear weapons.

'he (j⁶ ^~46 lightweight torpedo is the other torpedo in f_0rm ' jT operational inventory. Its successor, the Mk-50, devei ^ *^{cnown as the} advanced lightweight torpedo, is in 8^ener°^^ment' ^k-46 falls into the second and third ()₀ .^nc function categories listed earlier: maneuvering- n_eu_vⁿ? ^torpedoes for manned delivery systems, and ma- (ej^^'r'ug-homing torpedoes for standoff delivery sys- f_0rni' ^In ^e manned system category, the delivery plat- _shi ^{S are} fixed-wing aircraft, helicopters, and surface the d i- ^e hghtweight torpedoes have shorter ranges, so thou ^{6 1Vei}T Pl^atf°^{rm mus}t drop the weapons within a few ljgh_t^Sancl y^ards of the target submarine. Used this way, tha_n^^e'^Tt torpedoes may be regarded as nothing more they °^m*ⁿ8 depth charges; they are small and light, so U g^Cf.ⁿ carried by aircraft and surface ships. (The 'Shtweight ASW torpedo program began with the 37q ^Ser'^es that entered service in 1951. Weighing 260- _Shi_DP°^Unds, they were intended to be launched from air- q ’ ^a'^rcraft, and surface ships.)

^SROpHt ^sur^^ace ship ASW capability consists of Pedo ^^aunched with either a lightweight Mk-46 tor- (j ^{0r a} nuclear depth charge, and Mk-32 tubes on all fixed ^Cru‘^sers’ destroyers, and frigates. Helicopters and clear ]^Vln® ASW aircraft are also configured to carry nu- Ui,tij ^c^^ar§^es (B57s) and Mk-46 homing torpedoes. Pedo ^reCently’ ^t*^ie relatively high accuracy of homing tor- siy_e t^{S COrn}P^ensated for their small amount of high explo- In t° ^^rov*^^e reasonable kill probabilities. tiona^¹¹^ ⁰¹ ^^uture conflicts at sea, the most likely opera- fi'ets ^C°^nt*!¹8^encies will be small incidents or limited con- tnode"¹ 'y^hich U. S. naval forces are confronted by a few elgetrj¹¹’ °^{Ut not} P^articularly “hard,” Third World diesel- ped_0e'^CL ^U*^5rnar'^nes- 1° ^such cases, current lightweight tor- j_l₀ ^{s ave} adequate destructive power for the ASW role. War J?_h^Ver’ 'ⁿ 'he less likely but far more serious case of ^torped' ^^ovaet Union, the existing lightweight U. S. be ade°^{eS n}°^W *^{ntlle f}*^eet’ ^anc*^even '^^e Mk-50, would not ^oviet^^U if^{6 t0 counter} 'he growing numbers of advanced is to buTi ^arines. The trend in Soviet submarine design difficult *^aiT^{er un}'^{ts w}''h design features that make them to destroy. The 96-pound warheads on the Mk-46 and Mk-46 Neartip (upgraded) torpedoes are inadequate against modern submarines. Although the Mk-50 is pro­jected as having a slightly lighter, shaped-charge, jet- penetration warhead, this, too, may be only marginally lethal against the newer Soviet submarines.

The Third World scenario and the large Soviet inven­tory of older submarines will remain strong rationales for retaining lightweight torpedoes. However, the transforma­tion of the Soviet submarine force, although slow, will be sustained. Therefore, we must use a different approach to counter it.

The issue of nuclear-armed torpedoes to enhance weapon effectiveness is a result of considerations concern­ing the warhead’s weight and lethality. The issue also as­sumes that the torpedo has a role in the requirements for nuclear deterrence and controlling escalation. A reduction in the warhead’s weight could be achieved with a nuclear warhead. This weight reduction should result in an in­crease in the range or speed—or both—of a torpedo or missile. Such speed and range increases are desirable in light of the threat’s increasing capabilities.

A nuclear warhead is clearly superior to a conventional warhead when it comes to lethality. And since a nuclear warhead’s lethal radius is large (approximately 2,500 yards for a 125-kiloton warhead, or roughly equivalent to the search volume of a homing torpedo), requirements for very fine guidance devices are reduced. Moreover, im­proved lethality also overcomes the problems presented by the hardening and countermeasures of Soviet submarines.

Conflict at sea may be the only kind of nuclear war between superpowers that can remain localized and lim­ited because of its remoteness from homelands and the absence of major collateral damage. The Soviets might choose this option in a confrontation with the United States, provided conflict at sea was clearly secondary to the (nonnuclear) land battle. Naval theater nuclear force policy to combat this strategy requires nuclear weapons for deterrence and escalation control.

Specific issues to be addressed in examining the politi­cal value of nuclear torpedoes are the following tradeoffs in weapon effectiveness:

• Since a nuclear warhead requires less accuracy and is relatively immune to countermeasures, in some cases it may be preferable to a homing torpedo. The accuracy of a short-range ballistic missile (e.g., SUBROC follow-on) would be sufficient if it carried a nuclear warhead. Such a system would also have minimal flight time.
• Large, advanced-technology conventional warheads should be effective against the hardest submarines devel­oped in the next two decades. Larger torpedo tubes are planned for the next-generation U. S. attack submarines (Seawolf class). Larger diameter torpedoes would accom­modate heavier conventional warheads, but the main pur­pose for using larger tubes would be for obtaining quiet launch techniques.
• Sensor range and accuracy, more than warhead lethal­ity, will be the significant ASW problems of the future.
• The heavy torpedo is most effective at ranges where a nuclear warhead would be dangerous to the launching platform.

uainst

The United States must maintain a capability to < tactical nuclear warfare at sea for two reasons: th^st’ ^

Is it possible for nuclear weapons to be used only at sea without immediate escalation to full-scale nuclear war? Limited nuclear war at sea might rank in intensity some­where between nuclear war on land and nuclear conflict in space, which some observers think could occur without leading to full-scale nuclear war on the ground.

Several aspects of war at sea argue for the use of nuclear weapons: The targets are purely military; collateral damage is a lesser issue; no damage is done to the home­lands; media coverage is limited; and the combat is on neutral “ground.” Still, these nuclear explosions would not be completely isolated, and fallout could affect neutral merchant shipping and fishing vessels in some areas and situations. Underwater nuclear explosions, in which the bubble vents to the surface, produce fallout—as was seen at Operation Crossroads at Bikini in July 1946—that might reach landmasses as well as ships at sea. It may not always be practical, as in the case of a shallow-water en­gagement, to detonate weapons at an optimum depth from which no bubbles vent to the surface.

Early Soviet “declaratory” doctrine was black and white, stating that escalation of any U. S.-Soviet conflict to a nuclear exchange was inescapable. However, this rigid approach has become more flexible as we approach strategic nuclear parity. Soviet authors acknowledge that local or limited wars, where neither the United States nor the Soviet Union have vital interests at stake, could enter a limited nuclear phase—though this is not inevitable— without escalating to an all-out nuclear exchange.

How would the Soviets regard U. S. use of nuclear depth charges, torpedoes, or standoff weapons against a submarine? Would they respond in kind with nuclear at­tacks on U. S. submarines? Would they escalate but limit the conflict to naval warfare, perhaps by nuclear attacks on surface ships (especially aircraft carriers)? Would they launch an all-out strategic attack (against an enemy now possibly postured to launch on warning)? We have found nothing in Soviet naval literature that provides definitive answers.

There are a few clues. In Soviet thinking, land action always takes precedence over sea action. The Soviets probably will not “go nuclear” at sea before doing so on land, and Soviet actions at sea would be closely controlled from Moscow, at least in the initial stages of a conflict. Soviet naval doctrine calls for defensive operations imple­mented by aggressive offensive action. The prime targets would be U. S. nuclear-capable systems, especially air­craft carriers and ballistic missile submarines. If they at­tacked the latter, which the Soviets could attempt prior to any strategic exchange, Washington would have to per­ceive it as a very provocative assault on U. S. deterrence capability—far more provocative than a nuclear attack on an attack submarine. This leads to divergent possibilities. One is aggressive action, calling for immediate escalation. The other suggests no escalation at sea unless called for by the “state of play” in land action. Our original premise was combat at sea only.

Let us reverse the roles. What would be the U. S. re­sponse if the Soviets attacked one of our SSNs—not a ballistic missile submarine—with nuclear depth charges?

The Soviet Union is better prepared than the United Sta e to fight a nuclear war at sea. The Soviets have faced reality of nuclear warfare and at last worked out the the of how it should be fought. The Soviets have designs their forces accordingly. Their platforms are hea armed with numerous weapons and more closelyresem j truly dual-capable systems than the U. S. platforms, they stress nuclear defense at sea. Limited nuclear ^war^_g sea might be possible—but it would probably P^rove₁^,°_te(j an advantage to the Soviet Union and not to the un States.

Heavy torpedoes will continue to be necessary as range weapons for submarines, with lighter torpedoes sential for ASW air and surface delivery systems, ^u conventional torpedoes will encounter increasing ¹¹ tions on their effectiveness. Nuclear warheads are ^nL sary for both heavy torpedoes and standoff ASW ^111,5                  ^

for deterrence and for escalation control. Torpedoes nuclear warheads address specific applications:

• Increased-lethality heavy torpedo for use agains phoon SSBNs and Oscar SSGNs, and their ^succeS ^
• Lightweight torpedo homing warhead for delivery aircraft or missiles against time-urgent, hard targets
• Response to sudden deployment of effective countermeasures
• Response to ineffective conventional torpedoes ag

harder targets                                                                   _|Conduct

_                                    _____ _                                        first,

deterrent; second, as a hedge against the catastrophic ure of essential weapons—in this case, convention³ pedoes—as happened to the U. S. and German subm torpedoes in the early phases of World War II-

'See Labayie Couhat and A. D. Baker III, Combat Fleets oj the °r p_oj_niar, (Annapolis, MD: Naval Institute Press, 1984), pp. 497-510;       82---

Guide to the Soviet Navy (Annapolis, MD: Naval Institute Press, 1      ’

124.                                      '                                                                                            nderSub'

²Adm James D. Watkins, USN, Speech at change of command, Comma marine Force Atlantic Fleet, Norfolk, VA, 27 June 1983. _f intern*¹' ³Milan Vego, “Torpedo Armed Submarines, Part 2: 1961-84, ^a tional, March 1985, p. 142; also, Couhat and Baker, p. 704.  _ary

⁴John L. Butts, Director of Naval Intelligence, statement of 28 re pp. 5-6.  _afy i9&4>

⁵See Ralph E. Chatham, “A Quiet Revolution,” Proceedings, ^anU pp. 41-46.

Mr. Polmar, author of the Naval Institute’s reference books _reg_Uiar and Aircraft of the U. S. Fleet and Guide to the Soviet Navy, ^ j-_oreign contributor to the Proceedings as well as to other U. S. j\ⁿ _a| jnsti' professional magazines and newspapers. He was named            Kerr

tute’s distinguished author of the year for 1985. He and ■ corn- former members of the Secretary of the Navy’s Research Advi- ^ge. mittee (NRAC), and serve as consultants to the Department o

Dr. Kerr is Senior Vice President of EG&G, Inc., in Welles ey^ ^ [foe chusetts. Before assuming that position in 1985, he was direc Los Alamos National Laboratory.