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Assessing the CruiseMissile Puzzle:

How great a defense challenge?

Principal Investigator:

David Tanks

Washington, DC Office:1725 DeSales Street, NW Suite 402

Washington, DC 20036tel 202 463 7942fax 202 785 2785

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Graphics and Design | Marci R. Ball

Table of Contents

Section I: Introduction 1

Introduction 1Assumptions 6

Section II: Cruise Missile Threat Development 7

What Incentives Are Driving Cruise Missile Proliferation? 7Cruise Missile Acquisition Pathways 8Cruise Missile Proliferation 10

Section III: Cruise Missile Detection and Defenses 17

The Detection Challenge 17U.S. Programs for Countering Cruise Missiles 23

Section IV: Findings and Recommendations 29

Findings 29Recommendations 31

Appendix A: Cruise Missile Building Blocks A1and Modification Challenges

The Institute for Foreign Policy Analysis

i

Assessing the Cruise Missile Puzzle: How Great a Defense Challenge?


In ancient times, armies would surround a city and demand itssurrender. If the city resisted conquest, it would be brutallysacked if it fell to the invading army. The sacking of the citysent a strong message to other cities, making them afraid toresist unless they were confident they could withstand siegeand assault. Nuclear strategists claim that nuclear weapons rev-olutionized warfare because they make it possible to threaten acity without ever having to lay siege to it.

In the aftermath of the 1991 Gulf War, Russian and Chinese strategic thinkerspointed out that the precision-strike systems demonstrated by the United Statesduring Desert Storm were coming close to equaling nuclear weapons in strategicimportance. They were obviously referring to the potential for using precision-strikesystems to punish a country without having first to conquer it. In addition, someRussian and Chinese strategists have pointed out that long-range conventional pre-cision strike systems could be used to preempt nuclear strike systems (e.g., seeextract from Russian article, fig. 1, p. 2).1 Such a strike could be conducted eventhough the striking state had pledged no first use of nuclear weapons.

The lessons of the Gulf War were further developed during the 1990s. The keymilitary lesson learned by other states is that the United States is too powerfulto be challenged by conventional military means alone. Advanced information-ageweapon systems allow the United States to defeat industrial-age armies with lit-tle risk to forces or the U.S. homeland. The response of potential U.S. adversariesis to shift their focus to weapon systems that might enable them to hold theUnited States or its forces at risk during future crisis situations. Consequently, themost worrisome activities occurring deal with the development of weapons forwhich the United States possesses little or no defensive capability.

1 For a detailed example of this thinking see Anatoly D’Jakov and Eugeny Mjasnikov, “Precision Rockets Replace Nuclear,” Moscow,Independent Military Review, No. 4, February 4-10, 2000.

Introduction

Currently, the United States faces essential-ly four major emerging security challenges.Each has a tactical component that is appli-cable to military operations in support offriends, allies, and U.S. national interestsabroad, as well as potential situations involv-ing the strategic defense of the United Statesitself. The four challenges are:

• Ballistic missiles. Other than attackoperations before missile launch andthe threat of a retaliatory responseto such an action, the United Stateshas no national or theater-leveldefenses against ballistic missiles.Currently, the U.S. has only thePatriot system deployed to provideterminal defenses against tacticalmissile systems. A number of coun-tries are working to take advantageof this vulnerability.

• Terrorist attacks. The United Statesfaces the prospect that future terror-ist attacks against its forces or aU.S.-located target could involveweapons of mass destruction. TheUnited States needs to maintain suf-ficient freedom of action so as to beable to deter such an attack by hold-

ing sponsoring countries themselvesat risk. It must also be prepared todeal with the consequences of suchan incident if the terrorists are notdeterred and counter-terrorism oper-ations fail.

• Information warfare (IW). IW isbecoming a major concern as theinformation age evolves and a numberof states reportedly have begun todevelop the means for disruptinginformation-based systems. Militaryoperations, the U.S. economy, andmany facets of modern civilization arebecoming dependent on informationtechnologies. The IW security chal-lenge is the only non-lethal threat ofthe four cited above. Future U.S. vul-nerability to IW threats is expected toinclude threats to communicationsatellites and other space-basedassets as well as its domestic infra-structure such as air-traffic controland banking system.

• Cruise missiles (and related sys-tems). The United States can destroycruise missiles that have been detect-ed, but it faces a significant


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RUSSIAN ILLUSTRATIONS ON U.S. CRUISE MISSILE POTENTIAL Figure 1

These two Russian-produced charts reflect their perception of the potential for U.S. use of Tomahawk cruise missiles to preempt Russian nuclear systems.

challenge detecting the missile earlyenough to mount an effective defenseand target the missile over the hori-zon. Cruise missile developmentactivity reportedly is occurring in anumber of potentially hostile states,but analysts disagree on the speedwith which such a threat is evolving.The key issue in this debate centerson land-attack cruise missiles,although anti-ship systems continueto be of concern. (See figure 2.)

Cruise missiles are an obvious system ofchoice for conducting precision strikes. Theyare difficult to detect and can deliver a pay-load with great accuracy. Currently, over80,000 cruise missiles comprised of 75 differ-

ent systems are deployed in at least 81 coun-tries.2 The inventories of at least 20 of thesecountries include air-launched cruise mis-siles.3 As for the future, 42 new systems arereported to be in development.4 However,only the United States and Russia are knownto have cruise missiles with ranges greaterthan 1000 kilometers; China, Israel, and per-haps India are likely to join this club duringthe upcoming decade.

It must be understood, however, that thevast majority of the cruise missiles currentlydeployed are anti-ship systems not configuredto attack land-based targets. Roughly 90 per-cent of the existing missiles are short-rangesystems, having a range capability of about100 kilometers or less. The limited nature of


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THE FOUR EMERGING SECURITY CHALLENGES Figure 2

Terrorist WMD Attacks

Ballistic Missiles

KEY U.S. SECURITY

CHALLENGES

Cruise Missiles and

Aircraft

Information WarfareIncluding Disruptions to

Space Assets

2 Ibid., National Defense Industrial Association, “Feasibility of Third World Advance Ballistic & Cruise Missile Threat, Volume 2: Emerging CruiseMissile Threat,” Systems Assessment Group NDIA Strike, Land Attack and Air Defense Committee, August 1999, p. 136; testimony of Lt. Gen. JamesR. Clapper, Jr., Director, Defense Intelligence Agency, “Hearing on Worldwide Threat to the United States,” Committee on Armed Services, UnitedStates Senate, January 17, 1995 (Washington, DC: U.S. Government Printing Office, 1995) S. Hrg. 104-236, p. 64; and U.S. General Accounting Office(GAO), Defense Acquisitions: Comprehensive Strategy Needed to Improve Ship Cruise Missile Defense, GAO/NSIAD-00-149, July 2000, p. 5.

3 GAO Report, ibid.

4 Gjermundsen, op cit.

the current cruise missile inventory is expect-ed to begin changing in the near future. Atleast 9 or 10 states will soon be deployingland-attack cruise missiles with range capabil-ities spanning 100 to 1000 kilometers(medium range).5 Some of these new medium-range systems will be exported (e.g., Francehas already signed a deal with the U.A.E.).

It is uncertain how fast the more capableland-attack cruise missile systems will spreadto other international actors or whether manyof the existing short-range anti-ship cruisemissiles will be modernized or converted toland-attack systems. Moreover, since thetechnology involved in these systems is wide-ly available, it is possible that long-rangeland-attack cruise missiles could spread tonew international actors undetected. Itshould be pointed out that it is extremely dif-ficult to detect the development of cruisemissile systems; the potential for surprise isvery high. As Robert Walpole, the NationalIntelligence Officer for Strategic and NuclearPrograms, recently testified,

We ... judge that we may not be able toprovide much, if any, warning of for-ward-based ballistic missile orland-attack cruise missile (LACM) threatto the United States. Moreover, LACMdevelopment can draw upon dual-usetechnologies. We expect to see acquisi-tion of LACMs by many countries to meetregional military requirements.6

When Walpole’s testimony is matched withthe testimony of Vice Admiral Thomas Wilson,Director of the Defense Intelligence Agency, itis clear that the U.S. intelligence communityhas a high expectation that land-attack cruisemissiles will proliferate and pose a futurethreat to high-value targets. He testified that,

... the potential for widespread prolifer-ation of cruise missiles is high. While thetype of missiles most likely to be prolif-erated will be a generation or twobehind the global state of the art, statesthat acquire them will have new orenhanced capabilities for deliveringWMD or conventional payloads inter-regionally against fixed targets. Major airand sea ports, logistics bases and facili-ties, troop concentrations, and fixedcommunication nodes will be increasing-ly at risk.7

It is also clear that the types of systems thatwill be included in the proliferated threat willchallenge U.S. air defense capabilities. As wasreported by the National Air IntelligenceCenter, defending against LACMs will stressair defense systems.

Cruise missiles can fly at low altitudes tostay below radar and, in some cases, hidebehind terrain features. Newer missilesare incorporating stealth features tomake them even less visible to radars andinfrared detectors. Modern cruise mis-siles can also be programmed toapproach and attack a target in the mostefficient manner. For example, multiplemissiles can attack instantaneously fromdifferent directions.... Furthermore, theLACMs may fly circuitous routes to get tothe target, thereby avoiding radar andair defense installations.8

While it is generally agreed that LACM capa-bilities will proliferate and that thecapabilities of these systems will improve incomparison to those deployed today, there islittle agreement as to when LACMs will becapable of posing a significant threat to U.S.forces or the national homeland. Yet, the tim-ing issue is important because it has seriousimplications for U.S. cruise missile defense


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5 National Air Intelligence Center, Ballistic and Cruise Missile Threat (Wright Patterson Air Force Base, Ohio, NAIC-1031-0985-99, April 1999), p. 20.

6 Robert L. Walpole, “Prepared Testimony Before the Senate Governmental Affairs Committee Subcommittee on International Security, Proliferation,and Federal Services,” February 9, 2000.

7 VADM Thomas R. Wilson, Prepared Testimony Before the Senate Intelligence Committee, February 2, 2000.

8 National Air Intelligence Center, Ballistic and Cruise Missile Threat, p. 19.

development efforts and the potential num-ber of casualties the U.S. is likely to suffer infuture conflict situations. It is too importantan issue to ignore.

Although most of the foregoing overviewfocuses on land attack systems, anti-shipcruise missile systems are being improved. AJuly 2000 U.S. General Accounting Office(GAO) report states,

Current anti-ship cruise missiles are faster,stealthier, and can fly at lower altitudesthan the missile that hit the U.S.S. Starkin 1987, killing 37 sailors... The next gen-eration of anti-ship cruise missiles—mostof which are now expected to be fielded by2007—will be equipped with advancedtarget seekers and stealthy design. Thesefeatures will make them even more diffi-cult to detect and defeat.9

The growth in anti-ship cruise-missile capa-bilities has serious implications for U.S. powerprojection operations. Much of the recent U.S.military planning for naval use involves oper-ations in coastal regions in support of U.S.objectives on land.

For example, the spread of advanced anti-ship cruise missiles would make itincreasingly dangerous to operate U.S. war-ships in or near tense locations such as thePersian Gulf, the Taiwan Strait, or the YellowSea (west of North Korea—figure 3). The pro-liferation of advanced anti-ship cruise missilecapabilities could pressure naval forces tooperate further out at sea, thus limiting thedistance ashore that naval aircraft couldoperate or the size of the ashore engagementzone that could be covered by the planned


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HAZARDOUS NAVAL OPERATION AREAS Figure 3

U. A. E.

IRAQ

IRAN

OMANSAUDI ARABIA

PersianGulf

220km

180km820km 50km

CHINA

TAIWAN167km

CHINAEast

China Sea

SOUTHKOREA

NORTHKOREA100km

183km

9 GAO report, p. 6.

Naval Theater-Wide (NTW) ballistic missiledefense system to be deployed on Aegis cruis-ers around 2007-2010. Unfortunately, thecapabilities of ship-based defenses againstprojected cruise missile threats are not keep-ing pace with the anticipated deployment ofnew families of anti-ship cruise missiles.

To better understand the issues involved inthe cruise missile challenge, this mini-studywill examine the related cruise missile issuesin some detail. The study will note themotives and technologies driving cruise mis-sile proliferation, review proliferationindicators, then turn to the issue of defenseoptions for dealing with cruise missilethreats. Currently, the United States has verylittle capability to detect and track cruisemissiles. When reduced-signature technolo-gies are added to the mix, current defensecapabilities would find the challenge “missionimpossible.” Although the U.S. has somecruise missile defense programs on slowdevelopment paths, there is reason to ques-tion whether the current level of effort isadequate to deal with the evolving cruisemissile challenge.

Assumptions

Obviously, when projecting the future, someassumptions must be used. It is assumed that:

• The international system will continueto be dominated by the United States,with other major powers or would bepowers attempting to limit or circum-vent U.S. capabilities. A number ofmajor states, especially Russia, China,India, and France, have become veryopen in voicing dissatisfaction withwhat they call U.S. hegemony. Some ofthese states appear to be working tolimit U.S. freedom to act by permitting

technologies required for the develop-ment of weapon systems to supportasymmetrical defense strategies to flowto other states, especially those likelyto oppose U.S. intervention in theirregions. Although some of the technol-ogy exported is due to unsanctionedblack-market activities, it is also clearthat official acquiescence is involved insome known cases of sensitive technol-ogy transfers.10 It is assumed that thissituation will not change significantlyduring the next decade.

• The Missile Technology ControlRegime (MTCR) and other arms controlagreements and measures will nothave an appreciable effect on statesdetermined to sell dual-useaircraft/cruise missile components toother states. Essentially, this studydoes not envision a new internationalarms control agreement on cruise mis-siles or a significant strengthening ofcurrent MTCR provisions to preventsuch proliferation.

• That countries with cruise-missileaspirations will pursue cruise missileacquisition. In short, this studyassumes that countries will carry outthe programs that are under discus-sion or in development with regard tocruise missile systems.


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10 The international flow of technology with an expected intent of weakening U.S. dominance of the international community is discussed in somedetail in the study, Institute for Foreign Policy Analysis, National Missile Defense (Washington, D.C.: Conway Printing, July 2000), Chapter 1.

Although ballistic missiles provide a coun-try with a highly visible deterrent capability,cruise missiles are actually more versatile,accurate, and employable than are ballisticmissiles. The extensive use of the Tomahawkcruise missile by the United States during the1990s demonstrated to the world the value ofbeing able to punish or retaliate for violationsof international norms using a precision-strike conventional munition. The UnitedStates used cruise missiles in:

• Desert Storm, 1991 (Iraq)

• Southern Watch, 1993 (Iraq)

• Deliberate Force, 1995 (Bosnia)

• Desert Strike, 1996 (Iraq)

• Afghanistan/Sudan, 1998(Afghanistan and Sudan)

• Desert Fox, 1998 (Iraq)

• Allied Force, 1999 (Serbia/Kosovo)

In most instances where U.S. cruise missileswere employed during the last decade, the useof ballistic missiles, even with conventionalwarheads, would have raised the profile ofthose actions and likely would have resultedin widespread international condemnation,but cruise missiles and other precision strikecapabilities have coerced other internationalactors into complying with U.S. demands dur-ing the last decade without raising aninternational outcry. Other states, includingthe European Allies, have taken note of U.S.Tomahawk cruise-missile diplomacy and areinterested in developing similar capabilities.11

What Incentives are Driving CruiseMissile Proliferation?

For some countries, cruise missile technolo-gy offers the means for developing a precisionstrike capability much more cheaply thanwould be required to procure a modern airforce. Once built, cruise missiles require littlemaintenance and fewer trained personnel tooperate and deploy than does a fleet of jet air-craft. Moreover, unlike strikes from mannedaircraft, cruise missile use does not carry thepolitical risk of captured pilots. They are alsosuitable against both land- and sea-based tar-gets. Furthermore, cruise missiles are bettersuited for the delivery of chemical or biologi-cal munitions than are ballistic missiles.

Perhaps most important to modern warfare,cruise missiles allow a state to destroy specif-ic targets using conventional munitionswithout creating much collateral damage orinflicting many civilian casualties, a pointthat is particularly important in enforcementactions short of full-scale war.12 Cruise mis-siles are also capable of reaching through U.S.defenses and inflicting a significant level ofdamage and casualties on U.S. forces, a keyconsideration for many states seeking themeans to deter U.S. intervention in theirregion. Consequently, cruise missiles are themost likely weapon system to be actuallyemployed against a wide-array of U.S. targetsets. Thus, as states follow the U.S. examplein cruise missile acquisition and use, thesesystems will become a major threat to U.S.forces and perhaps the U.S. homeland. Themore puzzling questions are how quickly andhow extensively?


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11 For example, see Bernard Bombeau, “The Navy Wants Cruise Missiles,” Paris Air & Cosmos/Aviation International, March 31, 2000, p. 35, trans-lated in FBIS.

12 Robin Ranger, Humphry Crum Ewing, David Wiencek, and David Bosdet, “Cruise Missiles: New Threats, New Thinking,” Comparative Strategy, vol.14, 1995, p. 262.

Section II: Cruise Missile Threat Development

Cruise Missile Acquisition Pathways

Early cruise missile designs were based onan aircraft frame that had been modified forself-guidance or remote control and loadedwith explosives.13 Over time, the designs haveevolved to resemble missiles more closely inappearance—primarily as a means of reducingtheir volume so as to allow them to be pack-aged in compact launch tubes for storage,transport, and employment.

The formal U.S. Department of Defense(DOD) definition states that a cruise missile is“a guided missile, the major portion of whoseflight path to its target is conducted atapproximately constant velocity; depends onthe dynamic reaction of air for lift and uponpropulsion forces to balance drag.”14 The keyelements of this rather arcane depiction are1) that cruise missiles are guided (i.e., theyare not unguided rockets), 2) they are aero-dynamic (i.e., they do not operate outside ofthe earth’s atmosphere) and, 3) they fly totheir targets under power at nearly a constantvelocity (i.e., they are not gliders or mannedaircraft). In appearance, modern cruise mis-siles usually have short stubby wingsattached to a body shaped more like a missilethan an aircraft.

Unfortunately, the DOD definition isdesigned to specify the differences that dis-tinguish a cruise missile from, for example,an unmanned aerial vehicle (UAV). In termsof mission assignment, most UAVs are usedfor reconnaissance and surveillance missionsand are equipped to return to a home base. AsAir Force Chief of Staff General Ryan hasnoted on more than one occasion, cruise mis-

siles and other stand-off munitions are mere-ly UAVs on a one-way trip.15 Since there are 74different UAV systems in service and morethan 51 new models in development world-wide,16 they pose a significant potential foruse as precision-strike weapon systems infuture conflicts. UAVs and cruise missiles alsoshare many common components, both witheach other and with commercial aircraft.

If a country of concern (formerly calledrogue states) wanted to acquire a cruise mis-sile capability, it could: 1) obtain completemissile assemblies, 2) obtain, as a minimum,guidance systems, engines, and cruise missiledesign and guidance software packages froman outside supplier and assemble the systemindigenously or, 3) modernize or convert anexisting anti-ship cruise missile to a land-attack system.17

Option I: Procure complete systems froma producing state. Purchasing complete mis-sile sets is an attractive option since itprovides an immediate capability to field aproven system. However, this option has somehurdles in that most cruise missile producersadhere to the Missile Technology ControlRegime (MTCR). For MTCR member states, thetransfer of systems having a range of morethan 300 kilometers carrying a 500-kilogrampayload would be subject to challenge byother MTCR members as a Category 1 transfer.

Unfortunately, the MTCR has a loop-holeregarding cruise missile range classification,especially for air-launched systems that flylonger distances than a comparable surface-launched system due to the speed and altitudeof the launch.


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13 Systems Assessment Group NDIA Strike, Land Attack, and Air Defense Committee, “Briefing: Feasibility of Third World Advanced Ballistic & CruiseMissile Threat, Vol. 2: Cruise Missile Threat,” National Defense Industrial Association, August 1999, p. 65.

14 Joint Publication 1-02, U.S. Department of Defense Dictionary of Military and Associated Terms.

15 Kent Kresa, CEO Northrup Grumman, “For Unmanned Systems, the Time Has Come,” National Defense, July 2000, p. 8.

16 Ibid.

17 The three paths sited are extracted from a letter from Under Secretary of Defense Paul G. Kaminski to Congressman Floyd D. Spence, July 30,1996.

Option II: Indigenous development usingcomponents procured on the world market.If a state were to embark on development of anindigenous cruise missile capability, its pri-mary challenge would be the acquisition of themajor components needed to fabricate thesesystems. Since all of the technology used incruise missile systems is dual use, having botha commercial and a military application, it isnot difficult to obtain needed parts and com-ponents.

Cruise missiles are built around four keycomponent groups:

• Airframe (same manufacturing skills asrequired for light aircraft)

• Propulsion system (e.g., a rocket, turbo-jet, turbofan, or ramjet andcorresponding fuel supply)

• Guidance system (e.g., a INS, GPS, ter-rain matching, radar, IR, and/or video,and an electronic brain capable of inter-facing with the airframe’s flight controls)

• Payload (WMD or various conventionalmunitions)

Appendix A contains a complete discussionof the major components needed to buildcruise missile systems.

Option III: Convert or modernize an exist-ing unmanned aerial vehicle or anti-shipcruise missiles. Analysts are divided over thefeasibility of this approach. Of the many thou-sands of anti-ship cruise missiles spreadaround the world, most are limited in capabil-ity. Because countries, to include the UnitedStates, have difficulty identifying and target-ing ships over the horizon, there have beenfew incentives for developing anti-ship cruisemissiles (ASCMs) with long-range capabilities.

Typically, older ASCMs have ranges of less than120 kilometers carrying a 100 to 500 kilogrampayload. Their high-explosive warheads aredetonated by delayed fuses that allow the war-heads to penetrate a ship’s hull beforeexploding. Moreover, most ASCMs are equippedwith simple navigation and flight control sys-tems not suitable for land-attack missions.

ASCMs would need to be fitted with a newguidance system if converted to perform aland-attack mission. At a minimum, theINS/radar terminal guidance system used bythe ASCM would have to be replaced with anINS/GPS satellite navigation system, and theflight control system would have to be modi-fied to permit integration of GPS guidance.18

The degree of difficulty involved in this mod-ification would vary from system to system.On the other hand, even after guidance mod-ification, the resulting land-attack cruisemissile would still have a limited range capa-bility.

Airframes are designed to lift specified loadsbased on their aerodynamic lifting surfaces andflight velocity. Any attempt to increase therange of an existing missile would require somepossible modifications. These could includeadding more fuel-carrying capacity (perhaps bytrading-off payload), adjusting the balancepoint of the missile to prevent it from becom-ing nose or tail heavy as fuel is consumed,redesigning the wing elements to provide morelift, or possibly replacing the propulsion systemwith one that is more fuel efficient or providesmore thrust. These modifications could involvea major engineering effort.

UAVs. UAVs have the same four componentgroups as cruise missiles—plus a vehiclerecovery subsystem. Clearly, UAVs could bemodified for use as cruise missiles (usually


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18 For a critical assessment of the difficulty in converting an anti-ship cruise missile into a land attack system, see Steven J. Zaloga, “The CruiseMissile Threat: Exaggerated or Premature?” Jane’s Intelligence Review, April 2000, pp. 47-51. It should be noted that a couple of cruise missile engi-neers who reviewed this article claimed that it was not quite as difficult to convert the guidance system as was depicted in the article. They didagree with the comments on propulsion systems.

19 For examples, see Boris Tolav, “21st Century’s Super Arrows,” Moscow Rossiyskaya Gazeta, April 21st, 2000, p.3, translated in FBIS; and “Putin:Russia, U.S. Can Avoid Impasse in Tackling START III Problem,” Moscow Interfax, July 23, 2000, transcribed in FBIS.

20 Dmitriy Safonov, “Moskit Has Been Completely Declassified. The Chinese Navy Will Get A Unique Russian Missile,” Moscow Kommersant-Daily,April 14, 1998, p. 2, translated by FBIS.

with a light payload). However, if the landinggear or other hardware needed for vehiclerecovery were removed, the UAV would beable to carry a larger payload. Thus, UAVdevelopment also provides a potential routefor the development of cruise missile systems.

Of note, the most critical components forconstructing either cruise missiles or UAVsare engines and guidance systems.Unfortunately, these systems are the staplesof the commercial aviation world and could beobtained by a determined state. The MTCRspecifically excludes manned aircraft, anexclusion that provides a ready-made meansfor obtaining aircraft parts that could bediverted to cruise missile production. Infuture years, it likely will become even easierto obtain these components as commercialaviation activity grows.

Cruise Missile Proliferation

Within the context of the preceding discus-sion, a brief country survey is warranted. Thissurvey is not intended to be an exhaustivecountry-by-country review of cruise missileprograms, rather it is designed to provide aflavor of known cruise-missile developmentactivities.

In this case, the key word is “known.” Thecharacteristics of cruise missiles make themdifficult to detect; thus they are easily hid-den from space assets. Moreover, mostcountries of concern have put their missiledevelopment facilities and production facto-ries underground—preventing monitoring byoverhead assets. As a result, no person oragency can report with total confidence thecurrent status of international cruise missileproliferation.

Russia. Russian strategists claim that stand-off precision munitions, such as land-attackcruise missiles, are similar to nuclearweapons—because they allow a state to pun-ish other international actors without sendingtroops or manned aircraft across a border.Russian planners seek the aquisition of thesetypes of systems, especially in light of antici-pated reductions in nuclear force levelsresulting from a negotiated START III treaty orunilateral initiative.19 To the dismay of theRussian military, the dismal state of theRussian economy has stymied their efforts.There are, however, indications that the paceof development for next generation Russiancruise missile systems could soon increase.

For example, Russian military plannersreportedly agreed to declassify the Kh-41Moskit supersonic anti-ship cruise missile (amore capable version of the noted SS-N-22Sunburn) in hopes that international sales ofthis system will generate the revenue neededto produce a next generation anti-ship sys-tem. The Moskit, with a range capability of upto 250-kilometers, attacks its target at speedsgreater than mach 2 while making 10-g turnsto evade ship defenses.20 The Moskit has been


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YAKHONT 3M55 (SS-NX-26)

• Ramjet engine, 300km-range

• Payload: 200kg

• Some of its technology is used in Clubmissile family. (Club is an export system)

Russian air-launched version of newanti-ship missile.

Figure 4


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exported to China.21 Press reports indicatethat Iran may also have gained access to anearlier version of the Sunburn through a dealwith Ukraine.22

Russia is working to finish development ofthe 3M55 Yakhont (also called the Oniks—NATO designation SS-NX-26). (Figure 4) Themissile could be launched from ground, ship,or submerged platforms. It will have a maxi-mum range of 300 kilometers. The system isbeing developed as a follow-on to the Moskitcruise missile discussed above. Reports alsoindicate that Russia developed a land-attackversion of this missile, one capable of deliver-ing submunitions.23 The Yakhont initially willbe deployed on Russia’s new strategic sub-marines of the Yuri Dolgoruky class as theybecome operational beginning in 2005.24

Some components from the Yakhont havebeen incorporated into the Club (3M54E)(Figure 5) cruise missile system designed forexport and recently sold to India. China isalso interested in procuring the Club.

Russian military planners are not in agree-ment as to what type of future air-launchedcruise missile development they should pur-sue. One faction advocates deployment of amach-5 hypersonic cruise missile. The systemwould depend on speed rather than stealthfor its survival. Other analysts are advocatingproduction of subsonic cruise missiles thatincorporate signature-reduction technology.25

For the Russians, the problem is that U. S.development of anti-ballistic missile defensesand possibly tactical laser systems might leadto the emergence of technologies that wouldmake hypersonic missiles more vulnerable tointerception. In reality it is likely that Russia

THE CLUB MISSILE FAMILYANTI-SHIP SYSTEM WITH SOME SECONDARYCAPABILITY AGAINST FIXED LAND TARGETS

Figure 5Source: Russian Military Parade magazine, 2000

• Fired from surface ship vertical launch tubes or submarine torpedo tubes.

• Flies low subsonic cruise profile to 20km from target, then drops cruise-stage engine and flies supersonic to attack ships.

• Subsonic cruise missile launched from vertical launch tubes or submarine torpedo tubes

• Larger warhead then 3M-54E

• Anti-submarine missile with separable underwater rocket with homing sonar warhead

• Fired from surface ship vertical launch tubes

• Anti-submarine missile with separable underwater rocket with homing sonar warhead

• Fired from submarine torpedo tubes

3M-54E

3M-54E1

91RE2

91RE1

21 Ibid.

22 Sergey Viktorov, “Al-Ahram Article Cites Ukrainian Missiles to Iran,” Moscow Radio, May 12, 1993, translated in FBIS.

23 “Russian Federation, SS-NX-26,” Jane’s Strategic Weapon Systems, Issue 32, ed. Duncan Lennox (Coulsdon, Surrey: Jane’s Information Group,2000), p. 158.

24 “Russian Admiral Vaunts Naval Missile Systems,” Moscow Interfax, January 4, 2000, transcribed in FBIS.

25 Conversation with Steve Zaloga, July 24, 2000.


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26 Safonov, op cit.

27 Roy Braybrook, “Air-Launched Cruise Missiles,” Air International, July 2000, p. 50.

28 U.S. Department of Defense, Annual Report to Congress on the Military Powers of the People’s Republic of China, June 2000, p.16.

29 “China is Expected to have its Own Cruise Missile Soon,” PRC related web-site, www.chinaddict.com/military/cruise_missile, September 10, 1999.

30 Ibid.; and “China has Developed a Killer Land-Attack Cruise Missile,” Hong-Kong Sing Tao Jih Pao (Internet version), August 14, 1999.

would prefer to develop both subsonic reduced-signature and hypersonic cruise missiles. If ahypersonic system is produced, Russian cruisemissile designers plan to follow that develop-ment with a generation after next anti-shipcruise missile envisioned to have a velocity asgreat as 14-times the speed of sound.26

For the land attack mission, Russia is con-verting some of its 3000-kilometer-rangeKh-55 air-launched nuclear cruise missiles tocarry conventional payloads. This turbofanmissile system with inertial and terrain match-ing guidance, known in the West as the AS-15Kent, is a nuclear-capable system that maysoon be replaced by a new conventionallyarmed system known as the Kh-101. The newsystem has only been depicted in simple draw-ings, but reportedly may have a range of 5000kilometers carrying a 400-kilogram payload.27

Russia’s turbofan engine technology hasbeen weaker than that of the United States.However, there are hints that Russia is mak-ing progress on improving its turbofan engineproduction technology. It should be expectedthat Russian access to advanced commercialaviation propulsion systems will graduallylead to an improved engine production capa-bility in Russia. Thus, it must be anticipatedthat Russia’s long-range cruise missile strikecapabilities will improve in the future.

It also seems likely that some of Russia’scruise missiles or related components will beexported in light of the country’s continuedeconomic weakness and President Putin’sstated objective of increasing Russia’s defenseexports. The key unknown is whether Russiacan afford to produce these new systemswhile confronted by a mountain of pressingpriorities and few resources.

China. The People’s Liberation Army cloaksits military development in great secrecy,making it difficult to assess China’s defenseprograms. It is known that China has a num-ber of anti-ship cruise missiles, including the120-kilometer C-802 (discussed earlier). Chinais also acquiring Russian Moskit cruise missilesas discussed in the Russian section. China isalso in the process of trying to acquire 300-kilometer 3M54 Club anti-ship cruise missiles.What is less certain is the status of China’sland-attack cruise missile programs.

China is working on at least two long-rangeland-attack cruise missiles. The first is an air-launched system projected to be operational bymid-decade.28 It is likely that the missile beingdeveloped is based on the Russian Kh-65/SE(see figure 6), which is a 600-kilometer-rangeversion of the Kh-55 strategic cruise missile(air-launched turbofan with a 3000-kilometersrange).29 Reports indicate that China is devel-oping a 1500-2000 kilometer land-attack cruisemissile that uses a turbofan engine and mayinclude integrated inertial, GPS/GLONASS, andterrain matching navigation systems.30

KH-65 (AS-15 KENT)

• Turbofan engine, 600km-range

• Payload: 410kg

• China's program to build an air-launchedcruise missile is believed to be based onthis design

Russian air-launched land-attack cruise missile

Figure 6


13


Unconfirmed reports claim that this missilemay incorporate technologies taken fromrecovered Tomahawk systems and that Russiantechnicians are providing assistance.31

Although there is uncertainty as to howclose these cruise-missile projects are tobecoming operational,32 China clearly willhave a much greater cruise-missile capabilityby 2010 than it has today. Based on China’spast behavior in transferring ballistic missiletechnology to Pakistan, Iran, Libya, Syria, andother states, it is likely its cruise missile tech-nology may also migrate abroad.

India. India has at least three reportedcruise missile development programs: theLakshya, the Coral, and the Sagarika.

• The Lakshya is based on the designfor a pilotless target aircraft, whichfirst flew in 1985. The cruise missilevariant is believed to use INS and GPSmid-course guidance with radar or IRterminal seekers. The system isthought to have a 600-kilometerrange carrying a 450-kilogram war-head. An Indian turbofan engine wasflight tested on this vehicle in 1995(figure 7). An unconfirmed report in1997 suggested that this systemcould have a range objective of 2500kilometers.33

• The Coral program is designed to pro-duce improved Russian Moskit(Sunburn) anti-ship cruise missilesfor deployment on Indian destroyers.The existence of this program indi-cates that India likely has someSunburn anti-ship cruise missiles.

• The Sagarika program is believed tocover the development of both a bal-listic and a cruise missile fordeployment on its nuclear submarinewhen it completes developmentaround 2009.34 The cruise missile partof this program reportedly is focusedon providing a land-attack cruisemissile system that uses a turbojetengine to provide the missile with aplanned range of 300 kilometers. Thesystem is expected to incorporateterrain contour matching, INS, andGPS guidance systems. It will be ableto carry nuclear or conventional war-heads. An unconfirmed 1999 reportindicates that a follow-on version isplanned that will have a 1000-kilo-meter range.35

The Club cruise missiles India procured fromRussia are being deployed on its Kilo(Sindhurashtra class) submarine fleet.36 TheClub missile is produced in four variants to

LAKSHYA (UAV VARIANT)

• Turbojet engine, 600km-range

• Payload: 450kg

• Guidance: INS, GPS, and radar or IR

• Turbofan in development (2500km range?)

Indian UAV upon which land-attackcruise missile is based

Figure 7

31 Ibid.; and Jane’s Strategic Weapon Systems, Issue 32, “People’s Republic of China,” p. 3.

32 Ibid.

33 Jane’s Strategic Weapon System, p. 5.

34 Andrew R. Koch, “Nuclear-Powered Submarines: India’s Strategic Trump Card,” Jane’s Intelligence Review, June 1998, p. 30.

35 Ibid.

36 “India to Add Cruise Missile,” Aviation Week & Space Technology, March 27, 2000, p. 38.


14


37 Nikolay Novikov, “Russian Shipyard Begins Refit of Indian Submarine,” Moscow ITAR-TASS, August 7, 2000, translated in FBIS.

38 “Indian Navy to Induct Russian Cruise Missiles,” New Delhi The Hindustan Times (Internet version), December 4, 1999.

39 “China is Expected to Have Its Own Cruise Missile Soon,” op sit: and Jane’s Strategic Weapon Systems, p. 8 & 9.

40 Jane’s Strategic Weapon Systems, p. 9.

41 Uzi Mahnaimi and Matthew Campbell, “Israel Makes Nuclear Waves With Submarine Missile Test,” and “Fears of New Arms Race as Israel TestsCruise Missile,” London Sunday Times, Internet Version, June 18, 2000.

42 Dani Shalom, “IDF Denies Testing Cruise Missile Launch From Submarine,” Tel Aviv Hatzofe, June 19, 2000, p. 2.

include land-attack and anti-ship/submarineversions (see figure 5, 3M54E). Currently,India has only purchased the anti-ship ver-sion; India’s second Kilo submarine justdeparted a Russian shipyard in August 2000,modified to carry this missile system.37 Thereare indications that India may be planning onfitting cruise missiles on other warships forland-attack missions.38

Israel. Israel has developed anti-ship cruisemissiles to include the MK4 LR Gabriel. Thisturbojet cruise missile has a range of 200 kilo-meters, carrying a 240-kilogram payload.There have also been unconfirmed reportsthat a cruise missile variant of the DelilahUAV is being developed for China. The basicDelilah is a 400-kilometer range drone thatuses a small-US designed Williams turbofanengine.39 Israel has denied this report. Alsounconfirmed are reports that Israel may bedeveloping a supersonic cruise missile usingramjet engines. This project may have linkswith South Africa.40

In a recent development, the LondonSunday Times reported that Israel launched along-range cruise missile from a submarine inthe Indian Ocean. The missile was reported tohave a range of about 1500 kilometers (over900 miles), be capable of carrying a nuclearwarhead, and provide a retaliatory capabilityagainst countries such as Iran. The SundayTimes claimed that Israel plans to mount fournuclear-armed cruise missiles on each of thethree German-built submarines it is in theprocess of acquiring.41 Israel has denied thatit conducted the claimed test.42 Regardless ofthe validity of the reported missile test, thenews account is likely to help spur long-range

cruise missile acquisition efforts in a numberof Middle-Eastern states.

France, the U.K., Italy, Germany, andSweden. During the 1991 Gulf War, Frenchand British forces had few standoff weaponsystems. Many news accounts of that eranoted the need for Tornado aircraft and crewsto over-fly Iraqi airfields to drop crateringcharges. These European allies also noted theextensive U.S. use of Tomahawks and otherstandoff munitions, a use that reinforcedtheir previously drawn conclusions that theyneeded similar systems.

During the last decade, two groupings ofEuropean countries have nearly completedthe development of two very capable cruise-missile systems. The first is a stealthyFrench-U.K.-Italy turbojet powered cruisemissile system, the Apache (Storm Shadow)(figure 8). Of the three modular-designedmodels now being completed, the StormShadow achieves the longest range. It is an

APACHE (STORM SHADOW)

• Turbojet engine, 250-400km-range

• Payload: 400kg

• Guidance: INS, TERPROM, and IIR

• Sale contracted with U.A.E.Figure 8

France/UK/Italy air-launched, land-attack

cruise missile.


15


air-launched land-attack missile that can flyup to 400 kilometers carrying a 400-kilogrampayload.43 There are indications that a numberof additional variants of the Apache (abovethe three already in the works) may be devel-oped in the future.44

Of particular concern is the fact that Francedoes not consider the Apache to be an MTCRCategory I system and has contracted to exportthe Storm Shadow version of the Apache to theU.A.E. The U.S. objected to the sale, claiming thesystem is a Category I missile and that its exportwould violate MTCR standards. Nevertheless,France is proceeding with the export.Reportedly, Russia has taken particular note ofthis sale. Defense analysts worry that the exportof the Apache sets a precedent for future cruisemissile exports by other states.

The second standoff system is the GermanTaurus modular weapon system, which willhave a range of 350 kilometers. Germanybegan the program in March 1998. It is beingpartnered in this effort by Sweden. The sys-tem will be very technologicallyadvanced—adaptable to varying situations. Itwill utilize a smart warhead capable of pointand area attack. It can also be launched fromeither ships or aircraft and employed againstland or sea targets.45

Although the ranges of the systems notedwill be limited in comparison to long-rangeRussian and U.S. systems, the technology inthese two families of missiles is veryadvanced. It seems likely that these systemswill be exported to other states.

Other states. Many other states either haveor are expressing interest in acquisition ofcruise missile capabilities. There are numer-ous examples of this interest:

• North Korea reportedly is assistingIran with guidance improvements onthe Chinese C-802 anti-ship cruisemissile (which begs the question,what are North Korea’s cruise missiledevelopment capabilities?);46

• China and Iran have agreed to cooper-ate on a new generation of missilesand Iran is building anti-ship cruisemissile production facilities with helpfrom China;47

• Iran’s defense minister claims thatIran is about to deploy an extraordi-nary shore-to-sea cruise missile andbegin to manufacture its own lasergyros;48

• Iran may be capable of manufacturingturbojet engines, such as those need-ed to propel the C-802 Chinese cruisemissile that Iran is now producing;49

• There is an unconfirmed report thatIran may be working on a 400-kilome-ter range cruise missile;50

• Norway wants to acquire land-attackcruise missile systems as a means ofoffsetting anticipated reductions inits defense establishment;

43 Jane’s Strategic Weapon Systems, Issue 32, “France: Apache,” p. 69.

44 Bernard Bombeau, “The Navy Wants Its Cruise Missile,” Paris Air & Comos/Aviation International, March 31, 2000, p. 35.

45 Nick Cook, “Europe’s Cruise Missile Conundrum,” Interavia Business & Technology, Vol. 53, Issue 621, June 1998, p.39.

46 Michael Evans, “Tehran Upgrades Chinese Missile,” London The Times (Internet Version), January 11, 2000.

47 Bill Gertz, “Pakistan Gets More Chinese Weapons: Beijing Also Sells To N. Korea, Iran,” The Washington Times, August 9, 2000, pp. A1, A8; andBill Gertz, “Cohen Sees Iran Making Progress With Missiles,” The Washington Times, July 18, 2000.

48 “Defense Minister Inaugurates Project To Manufacture Laser Gyroscope,” Tehran Vision of the Islamic Republic of Iran Network 1, August 28, 2000,translated in FBIS.

49 John Mintz, “Tracking Arms: A Study in Smoke,” The Washington Post, April 3, 1999, p. A3.

50 Jane’s Strategic Weapon Systems, Issue 31, “Iran,” p. 7.


16


• South Africa has developed anadvanced cruise missile with a 150-kilometer range.51 (Figure 9)

It seems clear that momentum is building—cruise missiles are going to become a majormissile challenge to U.S. security.Unfortunately, there is no way to know howquickly these programs will come to fruition.For the past ten years, warnings that “thecruise missiles are coming” have been sound-ed repeatedly. For some, the situation isbeginning to resemble the traditional Jewishinvocation at Passover celebrations duringthe Diaspora, “next year in Jerusalem.” As aresult, policymakers are beginning to ask,where is the cruise missile threat? Yet a care-ful review of known information indicatesthat work is being undertaken on these sys-tems and that a threat is certain to emerge.Unfortunately, it is difficult to determineaccurately how close many of these systemsare to being deployed. There is a clear possi-bility, and perhaps even a strong likelihood,that U.S. forces could be surprised by the useof these systems during a future crisis.

TORGOS (NOV 1999)

• Turbojet engine, 300km-range

• Payload: 500kg

• Imaging IR w/digital data link. Has auto-matic target recognition.

• Optional low-light TV camera

• Accuracy of 2m CEP claimed

South African air-launched, land-attack

cruise missile.

Figure 9

51 Ibid., p. 12.


17


Section III: Cruise Missile Detection and Defenses

A typical modern cruise missile usually isabout six meters in length (give or take oneor two meters) by one-half to three-quartersof a meter in diameter. Most systems, espe-cially those with longer-range capabilities, flya high-low flight path to their target.Initially, the missile flies at a higher altitudeto conserve fuel, then drops down as it nearsits target to fly as close as possible to theearth’s surface. In the case of more advancedland-attack systems, the flight paths usedduring the nap-of-the-earth portion of theirflights are programmed to use valleys, terrainmasking provided by hills and mountains, andto use the earth’s curvature to avoid detec-tion for as long as possible. Consequently, thegreatest challenge facing cruise missiledefense planners is to detect and track the

missiles early enough to engage them beforethey reach their target—and to do so usingthe most cost-effective methods possible.

The detection challenge. Space-based sen-sors cannot detect weak sources of infraredthat are masked by a heavy cloud cover.Unfortunately, there are many parts of theworld that are cloud-covered much of the time.For example, southern China and the equatori-al regions of the globe located 10-degreesnorth and south of the equator (an area knownas the cloud belt) are usually obscured byclouds; other regions experience similar cloudpatterns and cannot be monitored routinely byspace-based optical sensor systems (figure 10).In the case of satellites deployed in geosta-tionary orbits to monitor missile launches,such as the Defense Support Program (DSP)

CLOUDS: A MAJOR IMPEDIMENT TO SPACE-BASED OPTICAL SENSING Figure 10

Visual and infrared sensors cannot “see” through cloud cover. Cruise missiles can be tested below this cover.


18


RADAR DETECTION TUTORIAL

The Effect of a Reduced-Signature ShapeIf the planes of the object are angled such that the signal is reflected in directions other than back toward the radar's receiver (figure c), the radar may not detect enough of a signal to allow the object to be discriminated from the electronic noise created within the system.

Radar Cross Section (RCS) measurement standardThe strength with which a radar signal will be reflected from an object is called the radar cross section (RCS). The RCS is recorded in square-meters. The amount of energy represented by a one-square-meter RCS is equal to the amount of energy reflected from a sphere having a projected area of a square meter (see figure a):

The Effect of Flat Surfaces and Angles on the RCSWith a high-frequency, short-wavelength radar, such as an X-band system, a 4-inch square flat surface directly facing the radar's beam will produce a RCS of 1m2. That same square will produce a RCS of only one-tenth of a square meter if illuminated by an S-band radar (due to the wavelength differences) (figure b).

However, if the above shown cube begins to turn, an X-band will lose the reflected signal once the cube rotates 10 to 20 degrees. The S-band will not completely lose all signal returns until the cube rotates 30 to 50 degrees.

Proj

ecte

d ar

ea =

1m

2

fig. a

The formula for this calculation is: RCS = wavelength24π x Area2

Illustrative LowObserverable

Shape

fig. c

fig. b

4”

4”

X-BandRCS=1m2

S-BandRCS=0.1m2

Under these conditions, the object may not be detected until it gets very close to the radar's location.

Figure 11


19


constellation, they are too far from earth todetect cruise-missile flights.

Even the Space-Based Infrared System-Low(SBIRS-Low) satellite constellation, planned fordeployment around 2010 to support ballisticmissile defense efforts, will be unable to detectthe signatures of low-flying cruise-missiles rou-tinely, especially when rain or heavy cloudcover is present to obscure the IR signature.52 Itcould be, however, that in cases involving hotmissiles, such as those powered by ramjetengines or rockets, or when cruise missiles areflying at high attitudes or under a cloudlesssky, that the SBIRS-Low constellation might beable to detect and track those systems if it isgiven the mission to do so and programmedaccordingly. At the current time, cruise missiledetection is not a SBIRS-Low requirement andit is not yet clear how much potential that sys-tem might have against cruise missiles. The keypoint is that for the foreseeable future, spaceassets cannot perform the cruise missile detec-tion and tracking mission reliably.

Unfortunately, the difficult cruise missiledetection challenge is expected to becomeeven more difficult. As signature reductiontechnology gradually becomes embedded innew cruise missile systems, the difficultydetecting these threat systems will increase.Based on current projections, technical per-sonnel working cruise missile detection issuespostulate that it will be at least another threedecades before space-based sensors mightbecome capable of detecting and tracking low-flying cruise missiles reliably. Consequently,cruise missile target acquisition will remain amission dependant upon terrestrial-basedassets for the foreseeable future.

With but a few exceptions, radar is the pri-mary asset used for cruise missile detection

and tracking. Unfortunately, radar detectionof cruise missiles is difficult.

• First, a cruise missile, even one ofstandard design, presents a verysmall radar cross-section (see figure11 for insights into the radar detec-tion process).53 If a cruise missile isflying directly toward the searchingradar, a spherically shaped nose onthe missile will present a very smallradar cross-section, thus reflectingonly a very faint signal back towardthe direction from which the signaloriginated. On the other hand, if thenose of the missile is shaped to reducethe missile’s radar signature, the RCSwill be even smaller. The smaller thesignature of an object, the closer thatobject must be to the radar’s locationbefore it can be detected.

• Second, low flying objects are diffi-cult for radar to detect againstground clutter (trees, birds, insects,moving water, people, vehicles, etc.all generate signal returns that mustbe processed by the radar). It is verychallenging for the radar’s computerto process the hundreds of thousandsof echoed returns from signals creat-ed by ground clutter and identify thefaint signature associated with acruise missile. The task is similar totrying to hear a pin drop in the mid-dle of an artillery barrage. Tominimize the amount of ground clut-ter included in a radar’s search area,ground-based anti-aircraft radar istilted back about three degrees to liftthe bottom of the search beam abovethe ground. However, this operational

52 For a detailed explanation of the SBIRS-Low program, see National Missile Defense, op cit, pp. 3.18-3.20.

53 For those interested in gaining a more detailed understanding of radar functioning and methods for decreasing radar signatures, see J. C. Toomey,Radar Principals For the Non-specialist, 2nd ed. (Park Ridge, New Jersey: Scitech Publishing, Inc., 1998); the small RCSs for cruise missiles andreduced-signature technologies is discussed in Humphry Crum Ewing, Robin Ranger, David Bosdet, and David Wiencek, “Cruise Missiles: Precisionand Countermeasures,” Bailrigg Memorandum 10, Centre for Defence and International Studies, Lancaster University, 1995, p. 50.


20


requirement makes it even more diffi-cult for ground-based radar to detectlow-flying aircraft or cruise missiles.

• Third, the earth’s curvature severelylimits the distance at which aground-based radar can detectobjects near the surface. As shown infigure 12, missiles or aircraft flying nearthe earth’s surface cannot be detectedby ground- or ship-based radar untilthey near the radar’s location.

Complicating the radar detection challenge isthe trend toward incorporating signature reduc-tion technology into cruise missile designs. Itwas discovered during the 1970s that by forming

the sides of an object in flat planes (calledfacets) set at carefully calculated angles to theanticipated direction of likely radar searchbeams, the echoed energy would be reflected ina different direction. Since very little of the sig-nal is reflected back to the point oftransmission, the radar cannot discriminate thefaint echo buried in the electronic noise of thereturns until the object of interest gets closeenough to the radar for the echoed signal tobecome stronger and more distinct. Moreover, tofurther complicate the radar challenge, anadvanced reduced-signature airframe designmight use special radar absorbing material onsurfaces such as the wing edges and other jointsin an attempt to further reduce the RCS.54

THE LIMITATIONS OF LAND-BASED RADAR Figure 12

54 The techniques used to produce reduced-signature aircraft were discussed in some detail on The History Channel, Stealth Technology: ModernMarvels, July 5, 2000, 10:00 p.m. The program included interviews with Denys Overholser, a key stealth design engineer for the F-117 Stealth Fighterin support of Lockheed’s Skunk Works during the 1970s, and Pyotr Ufimtsev, the Russian mathematician who developed the formula for predictingthe scatter of electromagnetic energy.


21


In addition, to mask engine signatures, theengine might be located behind and underthe body of the missile. This placement hidesthe engine’s fan blades from radar observation(the blades create a large radar signature).The missile’s body would also mask the IR sig-nature produced by the engine.

As was noted in the Introduction, it is notexpected that other states will produce cruisemissiles with the same degree of sophistica-tion the U.S. is capable of producing.However, it is clear that future systems willpose a greater challenge than has been thecase heretofor. The evolving cruise-missilethreat will require a new approach to targetdetection and tracking.

Since the curvature of the earth preventslow-flying cruise missiles or aircraft frombeing detected by a surface-based radar untilit closes on the radar’s location, any systemdesigned to counter a cruise missile threatmust use elevated sensors capable of seeingbeyond the earth’s local horizon. The systemsmust also incorporate advanced radar detec-tion technologies capable of processing andinterpreting very faint signal returns.

Theoretical approaches to reduced-signa-ture object detection. No object can becomeentirely invisible to detection. The simple pas-sage of an object through the atmospheredisplaces air molecules and disturbs the elec-tromagnetic spectrum. The key to detectingreduced-signature objects is to focus collectionefforts against those disturbances that cannotbe shielded. While it is much more difficult todetect objects that incorporate signaturereduction technologies, it is not impossible.

Bistatic radar provides a potential means fordetecting objects with a very small RCS.Bistatic means that the radar’s transmitter isseparate from the receiver. To put the systemin perspective, all early radar sets were bista-tic since the switching between transmit andreceive in the same antenna was not fast

enough—the pulse got back to the antennabefore the radar could switch to the receivemode. By necessity, the radio signal had to bebroadcasted by a stand-alone transmitter; thereturn pulse was recorded and processed by aseparate receiver. As technology advanced thetwo functions were combined into a singleequipment set that used a common antenna.

Almost all modern radar sets combine thetransmit/receive functions in a single equip-ment set. However, the need to detectreduced-signature objects is creating renewedinterest in the development of networkedradar sets that can receive and process theechoes of signals transmitted by other radiosources. In essence, the situation resembles abaseball game. Until now, all of the individualgames being played involved only a pitcherand a batter. The batter always bunted theball back to the pitcher. (See figure 13, p. 22)

The emergence of aircraft and cruise missileswith smaller RCSs are creating a requirementto field more players on the team, all of whomcan be kept aware of the common situationand all of whom are capable of catching a ballregardless of where it is hit (the echoed sig-nal). Likewise, it is clear that future detectionchallenges will require the use of bistatic radartechniques, networked into a system of sys-tems to detect targets that are difficult tosense naturally or that incorporate signaturereduction technologies. (Figure 14, p. 23)(Note: technically, situations involving multi-ple receivers and a common transmissionsource are called multistatic.)

The source of the radar signal transmittedfor bistatic detection can originate from asource other than a radar set. After all, theacronym RADAR stands of Radio Detectionand Ranging. Consequently, a radio signaltransmitted from any source could be incor-porated into a bistatic radar detectionsystem. In fact, China may be working onsuch a system to detect reduced signature


22


aircraft.55 The key to such a system is an abil-ity to network various radar receivers so as tobe able to detect and measure the outgoingsignal and the echoed returns, some of whichmight be reflected from an object in direc-tions other than back toward the radio source(e.g., a baseball hit to right field rather thanback to the pitcher).

Computer-processing advances are alsoopening the door to the development of moreadvanced radar processing capabilities,processes that can extract more informationout of the echoed returns. Moreover, new algo-rithms, such as those used in high-resolutionradar (HRR) could be discovered that willincrease radar efficiency. For example, some

BASEBALL/RADAR ANALOGY Figure 13

Current radar systems, each acting independently throw their balls (signals) to batters, who always bunt it back to the pitchers (radar transmitters/receivers).

What is needed is a team of fielders, who are all aware of the situation

on the playing field, and can catch the "signal," wherever it is hit.

55 Mai Shilong, “Window to China: New Radar Makes It Impossible for Stealth Fighters to Remain Undetected,” Hong Kong, Sing Tao Jih Pao, August16, 2000, p. A15, translated in FBIS. The Hong Kong article was based on an article published in a semi-open Chinese military monthly run by ChinaNorth Industries.


23


new discoveries, such as may evolve out ofultra-wide-band (UWB) technology, could pro-vide the means for future radar advancements.

U.S. Programs for Countering Cruise Missiles

The key issue is whether or not the count-er-cruise missile programs are evolvingquickly enough to protect against the emer-gence of more robust cruise missile threats.The cruise missile defense programs beingpursued or contemplated are focused on threegeneral areas of endeavor:

• Advanced sensors for use on elevatedor airborne platforms

• Netted sensor capabilities (i.e., the fullbaseball team)

• Low-cost interceptors/kill mechanisms

As was described in the foregoing section,curvature of the earth and terrain masking arehuge obstacles to early detection of cruisemissile attacks (see figure 15, p. 24). It isclear that any effective defense against cruisemissiles must be based on elevated sensorsoperating within a common network. Once thecruise missiles are detected and tracked, theymust be destroyed, preferably using low-costinterceptors launched from firing locationsbeyond the horizon of their intended targets.

There are a number of programs beingworked with varying degrees of intensity andwith differing levels of inter-service coordina-tion to try to improve the United States’capability to counter the evolving cruise mis-sile threats. Although there are fewopen-source details available on some of

Strong Reflected Signal

Very Weak Reflected Signal

KEY

Figure 14

RadarTransmitter

Radar Receivers

BISTATIC (MULTISTATIC) RADAR DETECTION OF REDUCED-SIGNATURE OBJECT


24


these programs, there is enough informationto make some judgments on the general direc-tion of U.S. cruise missile defense efforts.

Airborne Warning and Control System(AWACS). The Navy’s E-2 and the Air Forces E-3 AWACS aircraft monitor air traffic operatingin their sectors, provide military air trafficcontrol, and vector friendly aircraft againsthostile air threats (among other missions).These aircraft are large platforms operated bylarge crews; AWACS aircraft are unquestion-ably superb assets, but they are also expensiveto operate over prolonged periods of time.

As cruise missiles and other air threats withreduced signature technology evolve, thecapabilities of the AWACS aircraft must growin concert with those threats. Currently, theRadar System Improvement Program (RSIP) isbeing incorporated into the E-3, addingadvanced radar and sensor fusion capabilitiesto the aircraft to “capitalize on the newesttechnologies for cruise missile defense....

RSIP provides increased detection range forlow radar cross section targets.”56

Although there are few details available, theAir Force reportedly is examining ways of link-ing the search capabilities of AWACS withother platforms such as JSTARS. This type oflinkage would facilitate usage of moreadvanced radar detection techniques.However, this possible course of action is stillin the conceptual stage of consideration.57

F-15 upgrade program. By the end of 2000,an active electronically scanned array (AESA)will be installed on a small number of APG-63radar systems used by F-15C interceptors. Theupgrade will allow the aircraft to control a largenumber of advanced medium-range, air-to-airmissiles (AMRAAM), which are intended tointercept a swarm of cruise missiles scatteredover a wide area (i.e., provide mission controlsimilar to that of the AWACS).58 It is interestingto note that the first F-15C unit to be equippedwith this upgrade is located in Alaska.

0 50 150 200 250100

5000

10000

35000

30000

25000

20000

15000

PENETRATION ZONE

LINE OF SIGHTDISTANCE

TO HORIZON(curved earth)

CM USINGPENETRATION ZONE

Range (Miles)

Alti

tude

(ft

.)EARTH CURVATURE LIMITS CRUISE MISSILE DETECTION RANGES

Figure 15Extract from chart by Gordon Niva, Boeing.

56 General Michael E. Ryan, Testimony on the Air Forces Budget Request, House Armed Services Committee, February 10, 2000.

57 David Mulholland, “Joint STARS to Get Upgrades to Fly New Missions,” Aviation Week & Space Technology, August 9, 2000, p. 8.

58 Robert Wall, “F-15 Radar Upgrade Expands Target Set,” Aviation Week & Space Technology, December 13, 1999, p.40.


25


Expansion of the Navy’s CooperativeEngagement Capability (CEC) system. TheCEC development program is designed to pro-vide all ships in a battle group with the samesituational information. The ships will be ableto use data from other radar systems toengage targets outside the range of their ownsensor systems. To begin to examine the hur-dles to this concept, the Ballistic MissileDefense Organization (BMDO) is planning totest the concept in Fall 2000. As a prelimi-nary exercise, a small-scale test of a CECnetwork was conducted August 7-17, 2000 todetermine how much information the ele-ments could exchange. The elements involvedincluded a Wallops Island radar, a P-3 aircraft,two Patriot battery command posts and radar,

and an Aegis cruiser.59 There is also interest inexpanding this network capability to includeland-based air and other missile defenseassets. However, this program is a long-termevolutionary effort that is still in its infancy.It will require years to perfect.

Single Integrated Air Picture (SIAP). TheSIAP is a joint program to develop the capa-bility of a shared common depiction of allairborne objects, both friend and foe for allrelative assets in a theater of operation. Thisprogram would incrementally develop thesoftware and assets needed to integrate anddisplay information from the CEC, the JointTactical Information Data System (JTIDS), andIdentification Friend or Foe (IFF) signals from

NETTED SURVEILLANCE AND FIRE CONTROL Figure 16

59 “BMDO Successfully Completes Cooperative Engagement Capability Test,” Defense Daily, August 24, 2000, p. 7.


26


friendly air vehicles operating in the region.By creating a common picture of the opera-tional airspace, and therefore reducing theuncertainty of whether an object is hostile orfriendly, the various military forces in theaterwill have more freedom to act quickly in fluidsituations. (Figure 16, p. 25) The developmentof the SIAP program promises significantincreases in combat effectiveness. The SIAPeffort is being organized in late 2000.

The Joint Land-attack Cruise MissileDefense Elevated, Netted Sensor System(JLENS). The primary focus of JLENS is todevelop the advanced radar capabilities andcommunication systems necessary to networkthe sensing capabilities of the various systemsin a theater of operations. The JLENS programalso includes the acquisition of aerostat bal-loons to provide a low-cost platform to elevatethe advanced sensor systems needed for long-term observation of potential attacks.

The system will also control and guide inter-ceptors, such as Army Patriots andHUMRAAMs, Air Force AMRAAMs, and NavyStandard missiles that could be launchedblindly from beyond the horizon and guidedto intercept hostile targets by JLENS. Thiscapability was demonstrated on April 4, 2000when, for the first time ever, the control of amissile in flight was handed over to anotherradar (JLENS surrogate system); the missileachieved a direct hit on its target (ForwardPass demonstration). Since the JLENS pro-gram is a primary element of the cruisemissile defense strategy being pursued by theU.S. Department of Defense, a little timeneeds to be spent examining this program.

In a number of regions threat levels remainhigh on a continual basis. Places like theKorean DMZ, the Taiwan Strait, the PersianGulf, and Iraqi border areas all representregions that could require long-term counter-cruise-missile surveillance. As the futureunfolds, this type of mission could include

the Mediterranean and Black Sea regions ifhostile powers in the Middle East and NorthAfrica should acquire long-range land-attackcruise missile systems and threaten NATO.

To keep AWACS aircraft constantly aloft in these potential trouble spots would be avery expensive proposition that would entailthe deployment of an extensive support base.In addition, the constant use of these plat-forms would prematurely wear out thesevaluable assets.

In response to these emerging requirements,the Department of Defense established theJoint Land-Attack Cruise Missile DefenseElevated, Netted Sensor (JLENS) program todevelop advanced sensor and netted commu-nication systems that can be deployed forprolonged periods of time at reasonable costs.The system is not a replacement for AWACS,but rather designed to complement fixed-wingcollection capabilities. Most importantly, theJLENS program is designed to provideadvanced netted sensor capabilities that actas a gateway for linkage of all of the variousservice capabilities that could contribute toan effective defense.

At first glance, the JLENS program seemscomical in that the sensor suites being devel-oped will be deployed on large tetheredaerostats. Program personnel refer to the stan-dard reaction to the aerostats as the “gigglefactor.” The aerostat, when inflated, is two-thirds the length of a football field and wouldbe flown at the end of a slender 75,000-poundtensile strength power/data/anchor cable ataltitudes between 10,000 and 15,000 feet. Theballoons are envisioned to be employed inpairs, anchored by mooring trucks positionedabout five kilometers apart (see figure 17). Inmost cases, the five-person crews will be col-located with a Patriot battery; if they aresupporting naval forces operating in littoralwaters, they may be located on off-shorebarges or cargo ships to provide over-the-hori-

zon fire control against anti-ship cruise mis-siles or other air or surface threats.

The radar mounted under one of the aerostatswill search a 360-degree area out to a rangegreater than 250 kilometers and illuminateobjects of interest. The radar on the other aero-stat will provide precision tracking of objects ofinterest to a range of 150 kilometers. Operatingpower will be sent up a power cable inside thetether, and data will be transferred to and fromthe aerostat via a fiber-optic cable. The data willbe processed on the ground to minimize the sizeand value of the 6000-pound sensor packagehung under the balloon.

Unfortunately, there are several misconcep-tions about the aerostat that contribute to thegiggle factor. The myths that plague the pro-gram include:

• Myth 1: The aerostat is a big fat tar-get that would be easy to destroy. Itis true that the balloon is big andungainly; few will get excited aboutsuch a monstrosity. However, it is muchmore survivable than generally under-stood. Sensor systems on air-to-airmissiles are not programmed to lockonto this type of object. Radar beamsreceive little reflection from the round-ed shape, with most passing throughthe balloon; it has little IR radiance aswell. In addition, the JLENS system iscapable of shooting down aircraft andmissiles by controlling the fires of anydefensive asset in the area.

The more likely problem is that theballoon might be punctured by Cal .50machinegun fire (if hostile forces got


27


JLENS CONCEPT OF OPERATION Figure 17

within about a mile of the balloon.Since the internal helium pressure isonly slightly higher than the externalair pressure, any holes in the balloonwould not cause a massive venting ofgases, but would result in a gradualloss of helium as the gases slowlybegan to establish equilibrium withthe outside air. The balloon would stayup anywhere from a few hours to sev-eral days, slowly losing altitude. If thisoccurred, an AWACS or other similarsensor system would have to be movedon station to assume the mission untilthe aerostat could be repaired.

• Myth 2: The U.S. has AWACS, there-fore JLENS is an unnecessaryexpense. This statement is partiallytrue in that netted AWACS systemswould be capable of performing theJLENS mission. The issue is cost, plusthe loss of some other capabilitiesthat JLENS will bring to the fight.JLENS will cost much less to procurethan does AWACS platforms and itsoperating costs will be less than one-tenth that of an AWACS. JLENS isdesigned to supplement AWACS capa-bilities so as to free up those assetsfor missions that require the mobilitythat AWACS brings to the battlefield.In essence, JLENS will provide sentryduty while AWACS gallops off to leadcavalry charges.

It is also envisioned that JLENS willbe capable of providing informationon ground movements, a task alsoperformed by JSTARS. Thus, the sen-sor systems could provide both airand ground surveillance so that moreof the mobile assets can be deployedin areas with fluid situations whileJLENS guards fixed facilities or assetsthat are less mobile.

• Myth 3: A UAV could do the missionso JLENS is unnecessary. It is truethat the UAVs are extremely valuablemachines and have fantastic opticalcapabilities. However, large radar sys-tems are heavy and use largequantities of power. For continuouscoverage of an area, regardless of cloudconditions, the U.S. needs radar sys-tems. As noted earlier, the JLENSsensor package weights 6000 poundsand uses a fiber optic cable to down-link the massive data stream. UAVscannot handle this requirement on aroutine basis.

• Myth 4: Aerostats are fair weatherassets that will be down more thanup. It is true that severe weather willrequire that the system be grounded.However, aerostats can fly in winds upto 60 knots. Consequently, the systemis projected to remain on station forprolonged periods, only being reeledin for monthly maintenance orextremely severe weather, especiallyso during high-threat conditions.

The development of the JLENS hasbeen slowed in recent years as tightbudgets have squeezed defense pro-grams. As currently structured, theJLENS system is unlikely to bedeployed until 2010 or later.

Low-cost interceptors. The DefenseAdvanced Research Projects Agency (DARPA) isworking to develop low-cost missile systemsthat could be employed against cruise missiles.The objective of this program is to avoid usingtoo many multi-million-dollar assets to destroymissiles costing less than one-fourth as much.Therefore, DARPA is searching for low-cost killsystems that can be used to engage the cruisemissiles once detected. (This initiative also hasa sensor-related program that spawned theJLENS program discussed above.)


28



29


The speed at which highly capable cruisemissiles are likely to become a serious threatto U.S. forces, and perhaps even to the home-land, cannot be pinpointed. However, theinformation needed for U.S. policy develop-ment can be determined.

Finding 1: Countries should be expectedto seek advanced cruise missile capabilitiesbecause the benefits and motivations fordoing so are too persuasive for them toignore. They include:

• The success of U.S. Tomahawk diplo-macy. (Precision strike systems areseen as the military means that willbe used most often to resolve early21st Century conflicts.)

• Ballistic missile defenses willincrease the value of cruise missiles.(As ballistic missiles become vulner-able to counter measures, lessexpensive, but more versatile, cruisemissile systems are likely to becomethe system of choice.)

• Cruise missiles are highly useful forsituations requiring the use of coer-cive diplomacy. They also can beemployed against major powers with-out risking nuclear war. (The use ofcruise missiles for coercive diploma-cy is politically more acceptable thanis the use of ballistic missiles.)

• The precision with which cruise mis-siles can be delivered increases theirvalue. (Cruise missiles are much moreaccurate than are ballistic missiles,making them cost effective plat-forms for the delivery ofconventional payloads.)

• The limited amount of skilled man-power that is required to maintainand deploy cruise missiles is anattractive benefit for many states.(Many countries are finding it diffi-cult to train and maintain skilledmilitary manpower. Cruise missilescan reduce the size of this burden.)

• The survivability of cruise missiles.(Cruise missiles are difficult todetect and track in time to takeeffective counter-measure action.)

Finding 2: There are numerous indica-tions that interest in cruise missiledevelopment is gaining momentum. Someexamples include:

• Russia is developing long-range,land-attack cruise missiles, whileselling highly capable anti-ship sys-tems in an attempt to fundprocurement of next-generationcruise-missile systems.

• China is developing long-range, land-attack cruise missiles, whilepurchasing Russian Sunburn super-sonic, anti-ship cruise missiles. Newsreports indicate China may also beinterested in procuring Russian Clubcruise missiles.

• India is purchasing Russian anti-shipcruise missiles, while developing atleast three cruise missile systemsindigenously. Its 600-kilometer land-attack cruise missile may be fielded.

• Iran is building a cruise missile pro-duction factory and is upgrading itsChinese Silkworm anti-ship missiles.It is also working on building a UAV.

Findings and Recommendations


30


• North Korea and Iran are cooperatingon cruise missile guidance systems.This cooperation indicates thatNorth Korea may have an activecruise missile development program.

• Several European countries are devel-oping advanced cruise missilesystems that include reduced signa-ture technologies. France is sellingone of these systems to the U.A.E.(supply and demand indicator).

• South Africa unveiled a high-capable300-kilometer, 500-kilogram land-attack cruise missile in November1999. The missile has a very advancedguidance system. The manufacturerclaimed it has a CEP of 2 meters.

Since cruise missiles are built almost entire-ly with dual-use technologies, it is nearlyimpossible to monitor the international flowof parts and components used in these sys-tems. As a result, it is impossible to predictcruise missile proliferation rates.

Finding 3: Standard cruise missiles havevery low radar cross sections. A cruise mis-sile’s radar cross section becomes minutewhen signature reduction technologies areapplied. The United States requiresadvanced radar capabilities and sensoremployment approaches to deal withadvanced cruise missile and aircraft threats.

• Reduced signature objects requirethat radar detection systems becomemore capable, able to identify muchweaker radar returns than has beenthe case heretofore.

• Signature reduction technologies willdemand that sensor suites be net-worked together so as to allow use ofbistatic and multistatic radaremployment techniques.

• Since cruise missiles usually fly theterminal leg of their flights close tothe earth, elevated sensors arerequired to detect these systems whilethey are still behind the local horizon.

• The networked sensor system used todetect and track cruise missiles mustalso be able to control interceptormissiles launched blindly toward tar-gets that cannot yet be viewed bythe firing unit.

• The netted system must be able to con-nect and operate across military servicelines (connect together assets from theArmy, Navy, Air Force, and Marines).

Finding 4: The U.S. needs multiple capa-bilities that can link together to defeatadvanced air threats.

• AWACS aircraft from both the Air Forceand the Navy must be optimized todetect low RCS cruise missile threats.

• JSTARS aircraft should also be stud-ied to determine whether if can bemodified to detect small RCS low-fly-ing air threats.

• The JLENS program promises to pro-vide detection and tracking ofadvanced cruise missile threats at areasonable cost. JLENS is likely to bemost useful in areas of tension orunder conditions of limited conflictover prolonged spans of time. TheKorean DMZ, the Taiwan Strait, thePersian Gulf, the Iraqi border, andperhaps even some NATO border areasare examples of potential locationsfor possible JLENS deployment.

• The above programs also need theSingle Integrated Air Picture (SIAP)program to be successfully developedso that all service capabilities oper-

ate within a common situationalframework (i.e., all the ball playerscan see the entire playing field).

Recommendation 1: Since estimates ofcruise missile proliferation rates areuncertain, the U.S. should move smartly todevelop anti-cruise missile capabilities.

• The lack of anti-cruise missile capa-bilities is likely to encourage cruisemissile proliferation.

• Since the amount of work required todevelop the netted system of systemsneeded to detect and destroy cruisemissiles over the horizon is exten-sive, the United States cannot affordto delay this development until afterthe anticipated cruise missile threatsare already deployed.

Recommendation 2: The cruise missiledefense puzzle is very complex and noteasily solved. Consequently, theAdministration and Congress shouldensure that stove-piped service programsdesigned to counter cruise missile threatsare properly coordinated to operate withina common network of sensors and inter-ceptors needed to defeat the types ofsystems described in this study.

• It is not enough that a couple of sen-sor-platforms can coordinatetogether to detect cruise missilesover the horizon. U.S. securityrequires that a system of systems bedeveloped to counter the evolvingcruise missile threat.

• JLENS, AWACS, JSTARS, the Army’sPatriot and HUMRAAM interceptors,the Air Force’s AMRAAMs, and theNavy’s Aegis capabilities must all oper-ate as part of a cohesive andcoordinated force based on a commonsituational awareness. The cruise mis-

sile defense ball team needs a fullcomplement of players, not just anadjacent series of pitchers and batters.


31


Cruise Missile Building Blocks andModification Challenges

Defense analysts disagree on the speed withwhich the cruise missile threat is likely todevelop (to include suggestions that anti-shipsystems might be converted to land-attacksystems). To appreciate the basis for this lackof unity, it is necessary to briefly survey somecruise-missile-related technology issues. Toproduce an indigenously assembled land-attack cruise missile or to convert ananti-ship missile to a land-attack systeminvolves building a new missile or replacing atleast one or more components of an anti-shipcruise missile. This appendix will provide alayman’s overview of the issues involved.

The airframe. Since cruise missile designerswant to make their systems difficult to detect(and thus more capable of penetrating defens-es), it is desirable (but not required) to keepthe airframe as small as possible to minimizeits detectable signatures. The airframe needonly be constructed out of light aluminum oreven wood and canvas. Advanced technologyairframes may include or be built entirely ofcomposite materials, especially if the missileincorporates signature reduction technologies.

Since many of the underlying principles forreducing the radar cross-section of objects arecommon knowledge (an effort traceable to1944),1 it is clear that many of the recentlyunveiled cruise missile airframes have beendeveloped with the intent of reducing themissile’s detectable signatures. The airframehas been shaped to reflect radar echoes awayfrom the transmission source while the ther-mal infrared (IR) produced by the propulsionsystem is often masked. However, building an

airframe that incorporates highly advancedsignature reduction technologies is com-plex—the design must still be capable ofaerodynamic flight.

Engineers develop airframe designs based ona set of calculations that consider the inter-relationship between the planned weight ofthe missile, the velocity that its propulsionsystem can provide, and the amount of aero-dynamic lift that will be generated by thevehicle’s airframe, wings, and velocity. Inpackaging the missile’s components, the engi-neers also calculate fuel consumption and itseffect on the vehicle’s center of gravity as thefuel tanks or rocket motors lighten duringflight. The missile designers do not want thesystem to become too nose- or tail-heavy asfuel is consumed.

Many of the emerging cruise missile air-frames are incorporating composite materialsto reduce the weight of the missile and, insome cases, to reduce the radar reflectivityand the infrared signature of the system.Welds and rivets on aluminum airframesincrease the radar reflectivity of the body;however, in those instances where compositematerials are used, the airframe usually issmooth and shaped so that the radar crosssection and infrared signature are minimized.

In terms of cost and complexity, fabricationof the airframe (especially one of traditionaldesign) is fairly straightforward and is aminor portion of the cost of building suchsystems. If a country has a manufacturingbase for light aircraft, or some related indus-try, it could fabricate cruise-missile airframes.The major variable is the amount of signaturereduction technology that is incorporated.


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APPENDIX A

1 Systems Assessment Group NDIA Strike, Land Attack, and Air Defense Committee, pp. 44 and 120.

Propulsion systems. Although there are anumber of potential propulsion systems thatcan be used (even a piston-engine driven pro-peller), most cruise missiles are propelled byone of four types of engines: solid-fueledrockets, turbojets, turbofans, or ramjets. Itshould be noted that surface-launched turbo-fan, turbojet, and ramjet engines require abooster system to accelerate the missile tothe velocity required by that particular air-frame and main engine to sustain cruiseflight. For example, the World War II eraGerman V-1 missiles used inclined ramps andcatapults to launch the missile (figure 1).Modern cruise missiles equipped with air-breathing engines usually use a smallsolid-fueled booster rocket to blast the mis-sile out of its launch tube and provide theacceleration needed for cruise flight. In thecase of aircraft-launched cruise missiles, somedesigns use the speed of the aircraft to attainthe required cruise velocities. Each of the fourpropulsion systems cited below has advan-tages and disadvantages:

• Solid-fueled rockets are fast buttend to have a short range. Since theoxidizer required to burn solid fuel ispart of the fuel mix, cruise missilesusing this type of propulsion systemare relatively heavy and carry smallpayloads for a given airframe size. Itshould also be noted that the faster acruise missile travels through theatmosphere, the more intense its IRsignature will be due to atmospheric

heating of the airframe. Add to thissignature the heat of a burning rock-et engine, and it is easy tounderstand why rocket-propelledcruise missiles are easily detected byIR sensors and destroyed by IR-hom-ing warheads. At the same time,solid-fueled cruise missiles are simpleto design since the propulsion systemalso provides the boost needed tolaunch the missile. The French Exocetis an example of a solid-fueled anti-ship cruise missile. The longest-rangeExocet variant can fly 70-kilometerscarrying a 165-kilogram payload.(Note: some old cruise missiles heldin national inventories use liquid-fueled rockets with similarcharacteristics, but greater handlingdifficulties.)

• Turbojet engines produce highthrust levels, can obtain supersonicvelocities if so desired, and useatmospheric oxygen to oxidize fuel.However, these engines are not asfuel efficient as turbofan systems.Turbojets use a turbine-driven com-pressor to pack air into thecombustion chamber as needed toobtain the air-volume required forefficient combustion of the fuelbeing burned. Between the combus-tion chamber and the exhaust nozzleis a turbine that is turned by theexhaust gases to produce power to


A2


V-1: CRUISE MISSILE OF THE THIRD REICH Figure 1

turn the air-compressor blades. Theexhaust gases from the jet enginepropel the missile forward. Many ofthe cruise missiles currentlydeployed are equipped with turbojetengines. Since turbojets consume alot of fuel, turbojet-powered cruisemissiles have limited range capabili-ties. The Chinese C-802 anti-shipcruise missile, for example, uses tur-bojet propulsion. It has a range of120-kilometers carrying a 165-kilo-gram payload. Some emergingturbojet-powered cruise missiles haveranges of 350-400 kilometers. (Ofcourse, a passenger aircraft usingthis type of engine could be loadedwith explosives and used as a long-range cruise missile if cost factorsand radar-signature considerationswere ignored.)

• Turbofan engines are highly fuelefficient and quiet. They are thepropulsion system used to powerlong-range, subsonic cruise missilesystems. The turbofan engine worksby using a large fan to force air intothe engine’s combustion chamber atthe same time some of the air drawninto the engine is routed around theoutside of the combustion chamberand vented into the exhaust streamcreating added propulsion (figure 2).The air bypassing the engine alsoacts to cool the exhaust gases, reduc-ing the engine’s infrared signature.Since the engine is highly fuel effi-cient, it creates less exhaust thanother types of engines further lower-ing the missile’s IR profile. The U.S.

Tomahawk is the best example of aturbofan-equipped land-attack cruisemissile. The most recent Block IIImodel has a reported maximum rangein the vicinity of 1700 kilometerscarrying a 700-kilogram improved-explosive payload.2 An improvedmissile called Tactical Tomahawk isbeing developed and is expected tohave a range of 2800 kilometers.3

• Ramjet engines require a supersonicair flow to operate. They are alsoheavier-built engines than thoseneeded for subsonic flight. Theseengines are simple in that com-pressed air is provided by scooping itinto the air passage at speeds ofmach 1 or greater. The air is com-pressed into the combustion chamberby the shock wave of supersonicflight.4 Thus, ramjets eliminate theneed for the compressors and tur-bines used by other jet engines to gethigh volumes of air into the combus-tion chamber, but ramjets alsorequire the use of a rocket booster oraircraft to accelerate the missile tothe speed of sound. Once the soundbarrier is broken, or at least the airentering the engine achieves the


A3


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2 “World Missile Briefing, Missile Market Overview-Surface to Surface: BGM-109 Tomahawk,” The Teal Group, March 2000, p. 4. The range of theTomahawk is classified. The 1500 to 2000 kilometer figures are open source estimates.

3 Jane’s Strategic Weapon Systems, Issue 32, “USA (Tomahawk),” ed. Duncan Lennox (Coulsdon, Surrey: Jane’s Information Group, 2000), p. 194.

4 Some ramjets operate at high subsonic speeds by routing the air intake in such a way as to create a supersonic airflow even if the aircraft itselfhas not broken the sound barrier.

Figure 2: Turbofan engine

speed of sound, the ramjet can takeover the task of propelling the mis-sile using normal jet-engineprinciples. However, supersoniccruise missiles are more easilydetectable by defensive systems thanare subsonic systems. After all, it ishard to hide a very hot missile that isbreaking the sound barrier. Thus,they depend on speed rather thanstealth for survival. It should benoted that the feared Russian SS-N-22 Sunburn (Moskit) supersonicanti-ship cruise missile is an exampleof a ramjet propulsion system.

Guidance systems. As discussed earlier, theguidance system for an anti-ship cruise mis-sile can be very simple. A commercial inertialnavigation system (INS—measures movementrates and direction—provided by an integrat-ed gyroscope), an altimeter, a simpleautopilot, and a terminal radar-guidance sys-tem are all that is required. These systems arereadily available commercially.

Conversely, the land-attack systems requirea complex guidance system because land-attack cruise missiles usually are designed tosurvive by flying close to the earth. Thus, themissile must navigate around mountains, overor under tall power lines, and bypass othernatural or manmade objects if it is to arrive atits intended destination.

The initial U.S. land-attack cruise missilesrelied on INS and a terrain contour matching(TERCOM) guidance system to navigate to thetarget area. TERCOM uses digitized terrain-information maps that are stored in themissile’s memory banks. The cruise missileuses radar to scan the terrain it is passingover; it then compares the contour elevationinformation obtained to that stored in itsmemory. The guidance system requires

sophisticated programming. However, theUnited Kingdom has developed a similar sys-tem called TERPROM.5 Russia, China, and anumber of other countries have or are devel-oping their own terrain matching systems.

TERCOM/TERPROM navigation systems arevery work intensive in that they require thatthe regions where the missile will be used bemapped by radar or that high-quality maps bemanually transformed into digital elevationreadings and the resulting data used to createa digital map. The commercialization of spaceis making radar map data more accessible forpurchase on the open market thus reducing amajor obstacle to the development of a ter-rain-following navigation system.

The advent of the global positioning satel-lite (GPS) and its Russian counterpart,GLONASS, allows cruise missile designers tonavigate using commercial aircraft INS withintegrated GPS/GLONASS update capability.Both China and Europe have expressed intentto establish similar satellite navigation capa-bilities in the future to ensure that they arenot dependent on the United States for navi-gation data. Although the use of satellitenavigation requires detailed informationabout the terrain along the missile’s flightpath, it is a much less demanding challengeto use GPS/GLONASS than a TERCOM naviga-tion system. Consequently, satellitenavigation provides a means for developingstates to become cruise missile powers.

Cruise missile developers could also incorpo-rate a navigation system that uses a camera.If a video camera is mounted in the nose ofthe missile and used to fly the system byremote control via a television data link, themissile could be steered to a specific target bya human operator. This guidance system alsoallows the user to record reconnaissanceinformation gathered along the flight path,


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5 Jane’s Strategic Weapon Systems, Issue 32, “France: Apache (Storm Shadow),” p. 69.

to take evasive action in the event the missileis engaged by air defenses and to loiter in thetarget area and await the optimal time tostrike. These types of sensors and navigationsystems require communication relays if theflight path is long or the terrain is such thatthe missile’s data-link antenna could bemasked, interrupting the data flow. To thedismay of many engineers, maintaining thedata link for systems that operate over fairlylong distances has proven difficult. It canalso prove challenging integrating an accept-able antenna system into the missile’sairframe. Consequently, video navigationtechnology on medium or long-range cruisemissiles seems likely to proliferate more slow-ly than some of the other navigation systems.

It should be noted that a number of reportsof cruise missiles now in development in themajor states indicate that many of them willincorporate three guidance systems: INS, GPS,and terrain matching. This amount of naviga-tion redundancy will make it difficult todefeat these missiles using jamming or signaldenial tactics.

In the case of less advanced states contem-plating converting anti-ship cruise missiles toland attack systems, the key component thatmust be replaced is the guidance system. Forexample, putting a GPS receiver in the air-frame only provides coordinates of themissiles current location. Therefore, a modifi-cation of this type would also require that asystem be added to the missile that could cal-culate the flight path that must be flown andinterface with the existing flight control sys-tem to correct the direction and altitude ofthe missile. While this is not an impossibletask, it does require some skill.

The payload. A wide variety of munitionscan be carried on cruise missiles to includeweapons of mass destruction (nuclear, biolog-ical, and chemical) as well as a variety ofconventional options. Unlike ballistic mis-

siles, the accuracy of cruise missiles makesthem cost effective when used to deliver con-ventional warheads. Most cruise missiles inservice today have relatively small warheadsdesigned for anti-ship targets while land-attack systems generally carry largerpayloads. The known conventional payloadscurrently carried by various cruise missile sys-tems in support of land-attack missionsinclude high-explosive fragmentation, sub-munitions, runway cratering munitions, andcarbon filament warheads for neutralizationof electrical power grids. There are alsounconfirmed reports that some countries maybe developing or already have radio-frequen-cy warheads designed to overload and fryelectronic circuits.

Since the payload mass of these variousmunitions can differ, missile engineers mustmodify the airframe’s design, shift the inter-nal placement of its components, or adjustfuel or payload weight to handle the variouspayload options. As noted in the discussionon airframes, the components must be posi-tioned so that when coupled with theaerodynamic characteristics of the missile,the airframe remains stable during its flight.

Modifying Existing Anti-Ship Cruise Missiles

The degree of modification required to con-vert an anti-ship cruise missile into aland-attack system is dependent on the orig-inal design of the system in question. If thedesigner envisioned that the missile mightsomeday be converted into a land-attack sys-tem or had built the missile as part of afamily of missiles, the missile could havebeen designed to accommodate future modifi-cation requirements. Although modern cruisemissiles often are designed to accommodatefuture modification, older anti-ship cruisemissiles were built as specialized one-missionsystems. Consequently, the degree of difficul-


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ty that might be encountered convertingthese systems to perform a land-attack rolewill vary from missile to missile.

Figure 3 shows the line drawings of three dif-ferent models of U.S. Tomahawk cruisemissiles. All three models are packaged in thesame airframe dimensions, have the sameweight, and use the same engine and wing sec-tion configuration for the rear two-thirds ofthe missile. Although the Tomahawk wasdesigned for production in several variants andthus is more easily modified than are older sys-tems, it still lends itself as a convenient modelfor discussing modification challenges.

In figure 3, one can see that the TASM-B(top drawing) incorporates a radar (heavy inweight) in the guidance section and that themissile has a shorter range than the TLAM-C(middle drawing) due to less fuel capacity.Both models carry the same size payload.Consequently, the primary tasks involved inconverting the TASM-B into a TLAM-C are tochange out the guidance system and add morefuel carrying capacity to the forward section.The Tomahawk maintains a balanced center ofgravity over the wings by managing fuel drawdown in the various fuel tanks. Consequently,converting this type of cruise missile into aland-attack system is not very difficult.

On the other hand, if the airframe requiredmodification to accommodate a larger fuelsupply or payload, or if the engine had to bechanged out to obtain one that was more fuelefficient (increasing the missile’s range), onecan easily see that such a conversion couldbecome very complex. Many anti-ship cruisemissiles would require too much work to makeit cost effective to convert them to land-attack systems. It would be more effective toobtain the needed components and assemblenew systems in country.

It is the issue of feasibility and cost effec-tiveness that drives the debate among cruisemissile analysts. Yes, old anti-ship cruise mis-

siles could be converted to land-attack sys-tems. However, if only the guidance systemwere changed, the capabilities of these sys-tems would be very limited. Yet, if many ofthe other components were changed, thework effort and expense would climb rapidly.It may be more cost effective to build new,more capable systems. The disagreement piv-ots on how each group assesses this question.


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