HISTORICAL REVIW PROGRAM
RELEASE AS SANITIZED
SOVIET REACTIONS TO STEALTH
InfacMMionfmc in tbe prepunlnn of thu Estimate,wu approved br tbe National Porcarn IntcQuseiice Board* on
WARNING: Tbc maicrial io thisDistribution of
ifrtsclo lhc subject
ihc performance of ihctr duties.
THIS ESTIMATE IS ISSUED BY THE DIRECTOR OF CENTRAL INTELLIGENCE.
THE NATIONAL FOREIGN INTELLIGENCE BOARD CONCURS. the following inteHigoncp organization participated in the preparation ol Ihe Estimate:
Thegency, the Delem-gency. 1hc NoW Socurlry Agency, and lhe inrolliacoee oegoniroiion o) the Doporrmcnl ol Slolc.
The Auntarrf CMDmportwm* al the Army
The Cvettof olDepo<imenl ofNovy
The Aitntant CrMlIntdligence.m ol Iho Air Force
Tlic Counlcr-Slcallh Potential of Current and Near-Term
Early Warning Radar
Command, Control, and Communications
Future Soviet Technical
Early Warning Radar
Command, Control, and Communications
Ol her Defense
Prospective Soviet Stealth
The Impact of the*
Incorporating Stealth Vehicles in Soviet Military
Acquiring and Using Stealth
In recent years, the United States hasariety of design techniques, tliat will reduce the energy reQccted bv or radiated from aerodynamic vehicles and thereby decrease the likelihood of detection by enemy radar, infrared, and other sensors. The United Slates has also made significant strides toward the development of advancedlot the same purpose. This combination of innovative design and use of advanced technologies is known collectively as Stealth.
The well-pub|icizcd US Stealth development effort surely has generated concern among Soviet military planners aboul defense against low-signature and Stealth vehicles, ln addition to the need for increasing thc depth of its defenses by fielding more defensive weapons of existing types, the USSR will have to consider research andprograms lo improve the ability of those defenses to detect, track, and destroy Stealth vehicles. Thc degree of success that the Soviets achieve in these endeavors is certain to influence US military programs, strategy, and tactics.
We also anticipate thai the Soviets will develop systems of their own that incorporate signature-reduction designs and technologies. The USommunity must know as far in advance as possible the means by which the Soviets will reduce system detectability and the degree of their success. This will be necessary to aid in the development of US counter measures and to augment the US Stealth program because Soviet approaches may differ considerably from tliose under consideration for US systems.
This Special National Intelligence (Estimate is an effort to assess at the national level the Soviet capability and intention to respond to the US challenge. It presents our evaluation both of the defensive methods and technologies we believe the Soviets will employ to counter the US deployment of Stealth systems and of their technical capabilities to develop indigenous offensive low-signature and Stealth vehicles. The SNIE is restricted to discussing only aerodynamic and ballistic missile systemsyear period. It also identifies collection and analytic gaps that must be filled in order lor the Community to provide broader, more detailed studies in the future
Signature: The characteristic spectrum of radiated energy from the object. The source of energy may be the object itself, an incidental source whose energy is rcradiated from thc object,pecific source whose energy is rcradiated from the object. (Respective examples are infrared energy from an engine, visual energy from an object in sunlight, and transmitted radar energy returningadar receiver.)
Low Signature (Low-Observableharacteristic of any existingas an aircraft, cruise missile, reentry vehicle, orhas been modified to reduce its signature. Such vehicles can become ,less detectable lo enemy sensors within the limits imposed by the original design. Signature reduction for selected aspect angles or for all radiated or reradiatcd energy probably cannot be achieved for these systems.
Stealth (Vcry-Low-Observablehe sum ofdesign techniques and advanced technologies as expresseduture aerodynamic, missile, or space system developed to minimize external signatures. Such systems will achieve very low signature levels through special design to include careful shaping, by infrared andemission suppression, and by the application of.advanced coatings and material-Signature reduction for any aspect angle can be achieved in this type of design.
Radar Cross Sectionuantitative measurement of an object's visibilityadar as determined by the radar energy reflected by the object. The RCSehicle is determined by its shape andmaterial, the angle at which the vehicle is viewed, and thc frequency and polarization of the viewing radar. RCS is usually expressed in terms of square meters.
Infrared Radiationmitted or reflected heat energy in the near visible light freauencies. The total IR signatureehicle is the sum of its emissions, reflections, and engine exhaust. IR signature is customarily measured in units of watts per steradianunction of wavelength.
The Soviets are well aware of US plans lo develop Stealth aerodynamic vehicles; nevertheless, we judge that their air defenses will remain vulnerable to penetration by Stealth aerodynamic systems for at least lhe next decade. This judgment is basedumber of factors that include;
The limitations of existing Soviet sensors and information-processing systems, which were designed for use against high-signature vehicles.
The massive and capital-intensive nature of Soviet air defenses, which ncccssilales incremental modification rather thanreplacement.
The Soviets' lack of sophisticated measurement ranges, which inhibits their development of counters to the threat posed by Stealth.
The length of ihcycle, which almost certainly will delay the introduction of totally new defensive systems until
In the near term, (hc Soviets almost certainly willigher priority on developing defenses against US Stealth vehicles than on developing offensive Stcallh systems of their own. Indeed, the Soviets already have made certain incremental modifications to currently available defensive systems in reaction to the US deployment of cruisenaturally have the low radar cross section, low infrared signature, and low electronic emission characteristics typicaltealth vehicle.
The critical factor in determining the degree of success that Soviet air defenses will enjoy against low-signature and Stealth targets is the availability of adequate and timely warning information. Therefore, we expect the Soviets' near-term responses to include:
Upgrading the sensors and signal processors in current systems.
Increasing the dcplh of their defenses by extending ground-based and naval radar and fighter coverage offshore using Mainstay AWACS aircraft, aerial refueling,ewof more capable interceptor aircraft.
Further pairing of dissimilar types of radars to fill altitude and range detection gaps.
Increasing the numbers of selected detection and defensive systems.
Adding mobile surface-to-air missiles (SAMs) to the inventory to complicate penetration planning.
Increasing decentralized decisionmaking to counter overloading of their existing command and control system.
Additional netting of early warning,and SAM radars.
In the longer term, the Soviets are likely to seek technological solutions to the deficiencies in their air defenses that will persist despite thc near-term improvements, We believe these will include developing:
ow-frequency conventional radars incorporating new signal processors and electronic counter-countermcasures (ECCM).
Acoustic detection systems.
Improved infrared search and track sets (IRST).
Long-range air-to-air and surface-to-air missiles with multi-mode terminal seekers.
Fully automated command and control systems connected by digital data links.
Soviet Stealth Developments
The Soviets have an excellent theoretical knowledge ofand traditional signature-reduction technologies. However, achieving Stealth is dependent on the integration of shaping and other signature-reducing technologieseapon system.[_
[Jwe doubt that Soviet designers have as yet decided on an overall conceptual approach to any Stealth design. Therefore, while the Soviets probably will begin within five years to modify existing designs to reduce their external signatures, the length of ihe development cycle makes it unlikely that they could field an unmanned Stealth vehicle5anned Stealth platformo prolong the
service life of existing aerodynamicto control the risks associated with Stealthinitial attempt lotealth vehicle is likely to be an aii-lo-surface missile, followed by manned systems such as reconnaissance aircraft or tactical bombers, which depend on defense avoidance for survival.
The Soviets have shown an interest in signature-reducingwith broad applicationariety of aerodynamic vehicles and have acquired related technical information, materials, and manufac-luring equipmentariety of foreign sources. We periodically acquire information from articles in technical journals or from technical intelligence sources that leads us to believe that independent research efforts are continuing in:
Radar cross .section theory.
Automated Bight controls.
Infrared signature reduction
Electronics emission reduction.
The Soviets have three outdoor radar cross section ranges, thc most prominent of which arc at Kalinin and Voronezh.^
^jThesc facilities will contribute to both counter-Stealth and offensive Stealth developments butevel of technology several years behind that of the United States
Moscow has applied signature-reduction and -enhancementto ballistic missile reentry vehicles since the- The objective of this program might be toix of reentry vehicles, decoys, and other penetration aids thatariety of radar signaturesingle payload in ordor lo complicate targeting for antiballlstic missile defenses.
I The objective of tbe US aerodynamic Stealth program is to achieve andigh-coo bdenre capability lo penetrate the continuously improvlnc Soviet defenses, which reh/ on radar, infrared, and visual scroon lo provide target acquisition, ideniifica-tion, and tracking data to contiollm of Interceptor aircraft, surface-to-air missiles, and antiaircraftIf allacking'and cruise and ballisticnot acquired by Soviet seniors or If acquisition were delayed beyond the reaction lime of Iheir defensive network, the attacking force would be able to penetrate to its target without suffering an unacceptable rate of attrition Existing vehicles, modi tied to reduce their radar cross sectionnfrared (IB) signatures, and electronic emmrstaons. wiU degiade the capability of roost current Soviet defensive ivstems and render some others obsolete, but other factors must be considered in order to penetrate luture Soviet defenses Among these future considerations arecontrails, and reflected light.
lealth vehicle requires thai all of these factors be considered from design Inception. Shaping lo reduce radar cross section it Ihe most critical factor inlealth vehicle; reducing infrared emissions from the vehicle's propulsionwithout degrading performance isajor design challengeehicle's elect route emis-sions can be tracked byT systems, passive electronic subsystems or those designed toow probability ol intercept must also be developedI illustrates some of the desirable featuresleallh vehicle
Ihe Coonter-Steosfh Potentiol of Current and Near-Torm Soviet Systems
3 The Soviets are well aware thai ihe United Stales plans to improve its capability lo penetrate future Soviet ail defenses by developing aerodynamicwith reduced external signatures, althougheal certainly consider the impending introduction of Stealth technology as only the latestumber of technical and tactical changes that have forced the Soviets to read (soc inset) Moscow pe'erivei ihe
United States toignificant lead In theIechnologics and probably hat committedresources lo research efforts devoted lo counter the US systems
Ihe last two decades, thc Soviets haveas much on developing and deploying adefense-in depth as they have iheir offensivehave established an air defense system usingconcept that compensates for the ihorlIhe individual elements, but thu approach hasin an air defense network so massive andthat we believe their neai-lerm responsenew lineal will be limited lo systemincremental modification. Thc modificaiionsby the Soviets in response lo the USthe cruiseystem thai inherently has across section and low IRinitial response to Slealth deploymenl. Interm,ect Moscow to develop newand operational concepts that better matchpenetralion threat of US follow-onfor thc nesl five0 years lhc Soviets willto rely on defensive systems already In placepec ted to enter their inventory soon.
Early Warning Rodar Systems
The critical factor in determining ihe degree of success lhal Soviet air defenses will eniov against low-signature and Stealthhe availability ofsensori and signal reocessing Thc eiistlng Soviet air defense network Is alerted bv an extensive network of ground-based acquisition radars The Soviets will have several thousand early warning radars of someypes In service0 Although some of these have an excellent theoretical capability lo detect small targets under controlled cordilions, detection ranges would be severely degraded by low-level penetralion tactics, background duller approximating lhe return of Stealth vehicles, and olher riperalional consideralions.
In lhe near lerm, wc expect (lie Soviets to deploy combinations of these systems in order lo maximize iheir detection capabilities VHr' radars such as thc Tall King Cused as lhe acquisition radar for theurface-to-air missile and for ground-controlledsome tapabilityetect
Soviet Perceptioni ol Iho US Stealth Program
A great deal of attention in lhe Unitedevoted to expandingaviation capabilities in order to overcome the air defenses of thr Warsaw PactTo achieve Ihis coal, tbe Untied Slates isthe work on the "Stealth" program, which is attempting to develop metlsods that would substantially complicate detection of aircraft through air defense means using the principles of radio location or heat-seeking.
Tbeaircraft development programumber of Urge US aerospaceillion dollars for designing ibe fATB bomber was granted to theTbe Lockheed Company, using; lheit gained in designing thendis al present buildingeconnaissancehave received the designation CS1HS-is being financed by the project forthe future ATP fighter aircraft The Boeing,an. and Vought companies are abo participatingwork. In fiscal2 alone. Useillion dollars on this
ccording to American miliiary experts. Ibe development and deployment of "Stealth" aircraft will greatly Increase the surprise use of aircraft, becauseharp decrease in the dtttance at which they can be detected, and it will abo decrease Ihe efiecrtvencss of antiaircraft guided missiles, because of tbe decrease in the EPR and an increase In fluctuating errors when aiming missiles. Shortcomings of such aircraftertain decrease in aerodynamicsmall combat load because of the presumed
absence of external pods, as wellimitation in using navigational systems for operational activities and comorn
Although research In lhe "Siealih" program, wdcjng from Western press reports, is still io tlie upon mental stage, lite United States is already trying to determine future uses for "Stealth" technology In designing new types of tactical fighter aircraft, reconnaissance aircraft, and various unmanned systems and winged missiles. The main attention of the American admtlustration, however, is directed toward the development ofbomber aviation
lo accordance with the modern! ration plan for tlie strategic foices of the United Slates Air Force, serial production is being planned fee tbe ATB bombersmmediately following the completion of Ihc planned productionockwell BIB bombers. The ATB aircraft will be rigorously tested tn the processB production. Thus,B bomber fulfills two functions: ll Is an Intermediary strategic aircraft for penetrating the air defensesiobable enemy, and it servesuarantee in tlie event of failure of the Stealth concept.
If the ATB bomber is developed successfully, It can be deployedn thai case,f these aircraft will be accomplishins missions of penetrating air defenses instead ofB bombers, which would then be used only as carriers for winged roiaHes to be released outside lbc air defense rone of tho enemy.
The Moscow Journal ojefenses,3
radar cross section targets operating at high altitudes bui are less effective against such targets at low altitudes We believe the Soviets are more likely to pair thc 'Vail King with more effective low-altitude sensors-Ilke Big Back. Tall Back, and heightare already available, rather than Investajor modification to tlie Tall King itself.
aiwer frequency radars (that is. VHF) are more effective against low radar cross section targets because tlie radar wavelength approximates the length of the platlorm (see figurehey are. however, more susceptible to ground clutter. Thc Sovietsew VHF early warning radar, the Tall Rack, underWe expect this system, which uses an antenna rnasl abouleters high, lo be effective against low radar cross section vehicles operating at both high and low altitudes. If this new system is developedit could be deployed in the.
n addition to ground-based early warning assets, the Soviets are deploying their newCS aircraft (see figurewhich will be used to improve their offshore early warning capability. Thc radar on this aircraftatr-to-good capability against low-signature targetsoor capability against Stcallh targets at high or low altitudes, over land or over water. Tlie Mainstay's detection, tracking, and command and control capabilities will be an excellent adlunct to interceptors and SAM batteries facing conventional and,esser degree, low-signature threats. Target track data wtll be relayed from Mainstay to ground, naval, and airbornesystems through data finks, tlierebv alleviating some ol lhe operational problems imposed by low-signature and Stealth targets. We expectoainstay aircraft to be in the Soviet inventory
Katlar CapabflNic*w Radar <Ws Si'riiiui Targets
capabilityaiect depends Oti many (actors, including Ihc radar cross section (o) of Ihc urtcl any ihe diitanee (K> or .he rarccl from ilic.Mdar.7nc relationship liel.ven these factors is "pressed by Ihc jodat range cgujtHin.
Alagtreri fcwiiencjjilw ofthe recci.cd-
ru| decrease* al ill. rait of -
ar Clou lecooa a IIfaactM*At turn freoutnttei,api"eaencsvalue. Aiicuikiimo, Ihe rudar crosspeaks 'where the radarihe sire of sobm pian of the urges,III overall length or wing width-Urnreferred lo as resonance. Al very Sowthe iWn (im, section decrcatci U
The radar imec cqoiiaxairem lo Md calccaiuribtr urealbe rciurmd lo Ihr radar for sen soull values of radar*criion fthH* approachesrciomoth faster ni wtiaoa ar;rem. Up ratioran k- lie* lo R* rcniiins large even fixlir iron sc>tMmi) llmrUnr. for targeti Willi to- Bageli m
m. cuni'thulc atn 1V
signiil ashe taint mull This hailfund
leluin is calkJ duller'-So no!
lunr lhe fxenury chHieaelrtlM* ki le alio* ihem lo discriminate between itiir ia gen and duliri of Ih* same orradar erwii K*adii'l tkecerltcal craft fx* inotnetHal absrixe of clutter trotslythe capabilities of lhal radarow ladat crois setiion larad sn utimii dovu-nj't natal'1 cnutuM-rs <" adar con section UiiEetnclude Hw efheia of frequency, duller.ltitude, aspc.t, ard fliflit pr'i- Sockis bctnad Ihr wok of thi*
Fighter Aircraft System*
We do nor expect the overall force level of Soviet interceptor aircraft to chance appreciablyut the incorporation of aircraft now entering production or in the final stages of flight test will dramatically improve Soviet air defenses.boutercent of the Soviet fighter Inventory will consist ofoxhound,lanker, andulcrum aircraft equipped with pulsed-Dopnler redan with digital data processing systems, capable of conducting look down/shoot downcapability essential for defending against cruise missiles and low-signature aircraft but possessed bymallof thc current Soviet bghter inventory.
Al) threeheart of Soviet airsystems for at least the nextequipped with improved radars, fire-control systems, and alr-lo-alr
These three search track
(1RST) sets Q
ookdown mode or bad weather, this tracking capability would be severely degraded. Nevertheless. IRST sets provide an adjunct to radar attack bythe operator to passivelyarget or toarget in an ECM environment if some other sensor provides range data If the Soviets perceive that US developments in reducing radar cross section cannot be countered by radat Improvements alone, they may turn increasingly to infrared or olher passive sensors for detection, tracking, and missile guidance.
II In addition lo defending against penetrating fighter and bomber aircraft, the Soviets are threatened with offshore launches of cruise missiles We Judge
New Soviel Fighters
dcelrine, iheir future command and control structure, and their technological response to the increased threal.
ace-to-Air Missile Systems
he Soviets will have atissile (SAM) systems in the field and maydeploying ground-based laser defenses. Ascase of Soviet early warning radars, somecould threaten low-signature and Stealthunder certain conditions, but operationalreduce their effectiveness under
he USSR's longest range SAM. hatability to attack low signature targets,tlinie operated at low altitudes Nevertheless,of lhe Soviets' significant investment Inand its deployment in Eastern Europe,that Moscow will improve Ihetracking radars currently associated with the SA-5.
IS Theseehe Soviet Union's most modern strategic SAM, is the brst designed to defend againsi low-altitude aircraft and air-to-surface missile
production of new tanker and AWACS aircraft will support the Soviets' plans to move defensive forces further from their coastline in order to Intercept cruise-missile-carrying aircraft before missile launch. If (he newer fighters also aie equipped for aerial refueling, the Soviets could eatend their defensive barrier far enough offshore lo provide the prelaunch intercept capability wc believe they are seeking
hose targets that successfully penetrate the offshore barrier will be more difficult lo intercept over land even though the Soviets havetensive land-based defenses. Low-alhlude penetration tactics have already reduced track time and imposed clutloron Soviet radar and infrared sensors, reduced-signature systems will further Increase the Mresa on their defenses. Almost half of the Soviet interceptor aircraft will have some capability to attack low-signituie targets, unhiding cruise missiles, in0 time frame but probably will have little capability againit Stealth vehiclesS. Moreover, ibe effectiveness of individual air defense systems will be determined in laige part by lhe evolution of Soviet air
The SAIO will be lielded in two versions: iheversion -thenow beingthe mobilestill in development.
Then developments (he Soviets* latest tactical radar-guided SAM. liswhich incorporates two versions of an interceptorthe syslem to attack both high- and low-alfiluile targets ranging fiom cruise missiles to tactical ballistic missiles Its ability lo track low radar cross section targets could be improved by modifying its acquisition and engagement tadars to Include better clutter teicction in the former and towei mounting for the latter
Tbe Soviets have fielded large numbers of infrared SAM systems designed and developed inhat are highly mobile, easy to conceal, and relatively inexpensive lo build However, present Soviet technology in this area wdl notignificant threat to US low-ugnalure or Stealthin lhe near term, because even the newest Soviet
SAMs show only iv.4fmn.jl capabilities lo attack crime oiiviiIh Substantial improvements in infrared, sensing leehnologv will have to be achieved before these weaponi will he capable of attacking US Stealth
Anlwircrofl Artillery Systems
he .'i1t lhe current Soviet mobile radar-directed anliaircraft gun system It Is capable of tracking targetsadar cross sectionquare meter or larger. The follow-onystem could be improved by adding an acquisition radar, improving clutter refection, eliminating muliipalh tracking eirors, and upgrading its fire-controlRerause its range would be limited loilometers. Its usefulness againsi low'Signature and Stealth vehicles Is limited lo polnl defense of high-value targets We expect to see significanl numbers of tbeV fielded during the
Command. Control, and Communieolions Systems
he caiHing Soviet air defense system
Jgreat difficulty in trackingaircraft flying at low altitude Under some conditions. IH highly centralized slruclurc can inhibit the rapid Bow of information and firing decisions necessary lo engage and defeat fast-moving targets. The Soviets recognize that low-signature and Sleallh targets would severely stress their current network and are implementing procedural changes as stopgap measures until belter systems are available ineing forced to lowerto permil more rapid response to targetspilots, flight leaders, and SAM batleiyare bring taught to recognize an overload of the command and control system, and are beinglo engage targets on their own initiative, using local sensor and computational resources, without awaiting approval and target assignment from Iheir superiors
hile Soviet commanders are encouraging the development of autonomous command capabilities to overcome suine of thc deficiencies in their command and control system, they simultaneously urcthe role of centralized command and control by netting together early warning, groundand surface-to-air missile radars Tlie resulting networks capitalize on differences in sensor frequency, output power, and location toore complete picture of the aerialwithto low-aliunde pcnetraiors and low signature
vehicles such as cruise missiles. This sort ofis essential lo the orchestration of Soviet air defenses in response to the longer term Stealth threat, but sensor netting may produce overloading of the command and control system Until technicalin daia handling and integration areinformation from lhe netted sensors could contributehe elfedivcness of local air defense nodes but would providearginalIn lhe ability of Soviet commanders to manage the overall air ballle
mprovements will be necessary to correct lhe hardware limitations apparent in the Soviet air defense network. Existing Sovicl command and oontrol systems are basedne-on-onesingle Interceptor or SAMingle target. The new generation of interceptors now beingand lhe SA-IO system are capable ofengaging multiple targetsesult, the Lazur ground-controlled intercept system and theAM command and control system are being replaced by mote capable systems.
ew air-to-air. air-to-ground, and ground-to-air data HnksQ
jarcproviding better air situation information that will allow the Soviets to take full advantage of their new defensive systems The present objective appears to be one of providing decisionmakers in the cockpit or at the SAM battery level with enough air situation information to make correct cngagcmenl decision' This radical departure from historic Soviet practice is necessitated not only by the decreased reaction time available during engagements wiihsignaturebul also by the belief thai intensive electronic countermeasurc* may degrade command and .control, or that integral command, control, andnodes may be put out of action Centralized decisiontl^king is Ideal, bul in lhe above cases il also should be sufficiently flexible to allow engagement decisions lo lie madeevel appropriate to tbe situation The Soviets will retain centralizedwhenever possible
he Mainstay AWACS aircraft will enhance the Soviet alt defense command and control system by downlinking tracks of targets not visible lo ground sensors to giound stations via digital dala lignal Target information collected by the Mainstay's radar and IFF fidentification friend or foe) system probably includes idenli beat km. position, altitude, velocity, and number ot targetsroup We believe the Mainstay can manage up toimultaneous air hoiolled
intercepts, and control of soma Intercepts would be accomplished via air-to-air data links monitored by control leu aboard the Mainstay Tbe command,and communications capabilities apparent in the Mainilay system originally lesultcd ftom tbe Soviet perception of thc threat posed by low-altitude pene-tratori Although the Mainstayarginalcapability, it will serve as an interim Soviet command, control, and communications response to the Stealth threat.
Future Soviet Technical Responses
Early Warning Radar Systems
c are aware that the Soviets are developing higher powered early warning and intercept radars with the better resolutions necessary'to come lo grips with the low-signature and Stealth detection and tracking problem Soviet radar designers are likely lo incorporate VHF and UHF frequencies, increased pulse repetition frequencies, and improved signal processing in their nexl generation olbyulsed-Doppler processor. They may also develop spread spectrum radars io order lo make effective umming more difficult, however, these would not necessarily have improved capabilities against Stealth vehicles. These newer radars willlo have built-in electronic counter counter-measures (fcCCMJ based on such techniques as side-lobe suppression, waveform diversity, andcancellation.
likely to examine lhe following technical areas because ihey offer the greatest potential for improved perl or ma nee
Reduced radar fieqiiency to improve radar cross lection detection capability and lessen clutter Interference
Increased transmitter power, antenna apeiturc,
Increased signal-processing efficiency and clutter reduction through new waveforms.
Improved subclutter visibility through Internal refcrsernents
Future Soviet fntercrptors are certain to include much-improved IRST sets to enable Soviet pilots to conduct tailchase intercepts of low-signature vehicles Current Soviet IRST sets arc thought toery limited capability against low-signature targets and lose elfectivcness in clouds orluttered background If the Soviets are to improve significantly the capability of their IRST sets, they must develop improved sensors and,signal processors that can reject low-altitude ground clutter.
The Soviets have developed an autonomous midcourse guidance concept for their radar-guided air-to-air
Fighter Aircroft Systems
e are unable to determine the direction that Soviet avionics designers willpart because we expect new technologies tocertainavailable technologies offer the must likely avenues of approach to the problems posed by Stealth. If consistent with past practice, Moscow will upgrade the radar and Infrared sensors oa ils next generation of interceptors in an attempt to meet the Stealth threat. No single technology will correct the deficiencies of current Soviet air Intercept radars, but the Soviets are
rticles in Soviet technical journals havelaboratory-level optical processing of radar signals,.an indication of thc Soviets' interest in devel oping electro-optical adjuncts for airborne detection and tracking nf low-signature and Stealth vehicles. Opticalattractive alternative to lhe high-quality diciial technology on which US systemsincrease thc speed at which tadar data could be processed and would allow lhe detection ofnear-noise-level returns by providingcorrelation power and clutter rejection The Soviets have also demonstrated technology in operational laser rangeflnders. which could lead lo the development of
laser radar systems for the detection and tracking of targets. However, we have no evidence of suchat this time.
Surfoea-to-Air Missile Systems
uch of the detection and tracking technology developed for future interceptor aircraft could apply to ground-bared SAM systems Soviet eaperience in developing IRSTs for aircraft could lead to anground-basedapable of supporting cruise missile engagement by newer and future SAM systemsystem would require advanceddetector and signal-processing technology.^
ver the years, the Soviets have continued to upgrade the capabilities of their radar-directed SAMs to meet tbe evolving threat to their defenses.^
Commond, Control, and Commmunicrations Systems
s ihe US deploys and peilccts the penetration techniQues of vehicles thai have progressively lower signatures, we eapect lhe Soviets lo continuetheir acquisition and tracking tadar networks by improving Ihe data handling capabilities of theirand control systems in order lo provide lhe automated redundant links necessary to handle fast-
moving events throughout the Soviet ait defenseIf thc Soviets are to cope with the very short reaction limes imposed by Stealth targets, they must automate many if not all of the manual operations that inhibit their current air defense system Automating the system will require dcvetOpmenl of suitable system architecture, algorithms, andin which the Soviets most Lag Western computerhe Soviets are likely to conccntrale theii resources in this area because nf tbe potentialigh payoff against low-signature and Stealth vehicles
Ballistic Missile Defenses
he Soviets probabty believe that application of Stealth technology to US ballistic missile reentryis farther off. Their current ABM and ballistic missile early warning systems are based primarily on radar, and their launch-detection satellite* use IR sensors Thc Soviets are actively engaged In research on more advanced ballistic missile defense concepts that could Include directed-energy weapons. Should these prove feasible, the Soviets would have to develop more accurate tracking means that might couple optical techniques such as laser or IR tracking with advanced radar concepts tootentially effective counter to Stealth ballistic missile RVg
Other Defense Options
here are many oplions that thc Soviets might take in responding to the Stealth thrcal lhat are not technology dependent. Most would bo readilyto lite Intelligence Community and offer no long-term solution to lhe problems faced by tbc Soviet air defense system The options include
Ircieasing .the use of AW ACS aircraft, aerial refueling, and long-range interceptors lo eitend defenses Offshore barriers could be augmented bv naval radars, shlpbornend aircraft carrier*
Increasing the numbers of radars and SAMs lo offset lhe ieductions In range and reaction time imposed by Stealth targets.
Increasing the use of mobile SAMs lo complicate penetralion planning
Clearing obstacles around SAM sites andmore SAM radars on towers lo improve hne-nf-sight and reduce ground duller.
UsingHacking nets, human *potlcrs. and visually aimed antiaircraft artillery.
Using manmide nbstaclca such as barrage balloons.
Prospective Soviet Stealth Developments
The Impact of thorocess
he speed at which new technologies aremto Soviet offensive forces will be determined by the status of technologies in research and the com plenty of the systems entering development Tbe technology research phase can be shortened bytransfer if applicable Western technology can be brought lo tbe production line. The overall result is that system development can start earlier than would have otherwise been possible if thr Soviets had had lo rely on indigenous developments alone. However, Soviet designers tend lo select majon systemearly in the development process. The impact of this approach, in terms ol development loadttme. Is summarized in table 1.
Incorporating Stealth Vehicles into Soviet Miliiary Planning
ur iudgmenls oa how Soviet militar, phmners mightecision to incorporate Steahhin their future form are admittedly subjective Nevertheless. Soviet requirements to penetratedefenses appear to be the most difficult task for their forces for the present. Thus, lhe Soviets probably calculate that the most immediate need for Stealth technology lies with those forces Intended forstrike and tactical air operations, ami thai Stealth application to intercontinental bomber and long-range cruise missile designs may safely beower priority. In the longer term, the Soviets probably
Impact of iheD Cycle on Ihe Availability of Systems Incorporating; Stealth Technologies
lhal the US Strategic Defense initiative willumber of thc technologies lo improve early-warning of an enemy bomber attack andS deployment of ballistic missile defenses would be accompanied by air defense moderniaalion.
eripheral Strike and Tactical Airbe aerodynamicand cruiseSoviet theater forces faces an increasingly capable NATO defense. NATO air defenses,those in Central Europe, and lhe defenses over US carrier battleprimary large! of Soviet naval airrated aighly effective by the Soviets The Soviets have invested heavily in these forces over the lastears, deployingencer andackfire bombers thai were developed before signature reductionignificant design criterion. Tliesc aircraft probably will be the backbone of Ihe peripheral bomber forces throughout the rest of lhe century. The Soviets probablyeed to arm these altcrafl with low-signature air-to surface missilesnd perhaps field Stealth missilesbey will field follow-on aircraft thai are likely lo itieotporate some low-signature technologies.
oviet tactical air force operations areby air-superiority and ground attack fighters, and reconnaissance aircraft. The Soviets have Justdeveloping lheulcrum and thehat do not appear to incorporate signature-reduction technologies We judge that these aircraft will be the primary fighters in lhe Soviet tactical air inventory for yean to come and probably will be modi bed with some low-signature features during theii operational lives The design ofStealth fighter using technology currently available lo the Soviets probably would require sacrifices In flight performance that they are likely to considerin an air-to-air combat aircraft whereis an important aspect of survivability We therefore doubt lhe Soviets willtealth lighter before the neat century.
n the other hand, the current Soviet tactical bomber and reconnaissance force consists principally of aircrafl whoses designi offer Utilefor Increased range or pay load, or decreased eiignature. Aircraft in these categories would be less affected by the sacrifices In flight performance forced bv current Stealth technology because iheir pilots have traditionally depended more on avoidance than maneuverability lo survive For these reasons, we believe ihat an aircraft from one of these two mission areas is likely lo be the first manned system to licnefit from Soviet Sleallh technology
40forces. Thc Soviets aie well aware that the US SDI effort is not eipected to come to full fruition before livehis much leadlimc may allow the Soviets to investigate aof signature-reduction techniques and toeffective ones into their neit generationuiully reliable source recently reported that the Soviet* already are working on techniques to reduce the IH signatures of iheir ICBMn effort consilient with their program to reduce the radar cross section of ballistic reentry vehicles (see section on ballistic missile systems)
he Soviets might be especially motivated to incorporate signature-reduction techniques in their long range cruise missiles and, eventually, their Inter-cool mental bombers These systems have sufficient fleiibilily to allow them lo be usedariety of conventional and nuclear roles, and (lie development of low-signature and Stealth air-launched cruise tni*-siWs would extend the effective service life of the generation of bombers now deployed or in
Acqyring one) Using Sleolth Technology
oviet scientists have shown an Interest in slgna-ime ieduction technologies applicableroad cross section of aerodynamic vehicles They haved radar absorbing paint* and materlah for icveral venn and have acquired technical information,equipment, and materials from severalsources The obiect* of Soviet technical interest include:
Kadar-absorbing material* lhalighto decrease lhe effectiveness of certain tadars and millimeter-wave-guided weapons
Lorgc-scale carbonyl iron powder manufacturing facilities. The production capacity the Soviets seek is betond their normal military or civil lequiremenis
Large autoclave* suitable for making composite aircraft parts The number of autoclavesetceed* iheir basic research requirement.
eveloping Ihe technologies required by Slealth vehicle* will tu (heves* with foreignaisistance. hul production of such vehicles may be an even more formidable lask. Careful attention lo qualityong-lerm weakness uf Soviclnecessary lo minim ire lhe ugnature of any given design Retraining production personnel inlo
highly skilled technician* will be time consuming and will put additional stress on the already burdened Soviet mllilorv-produr! work force.
A prerequisite lo developing Stealth vehicles is lhe ability to measure very small changes in the energy emittedflect ed bv prospective designs The most challenging of theselhe radar cross section of Stealthbe doneighly instrumented indoor or outdoor range While initial radar cross section meuurcmtnl* can be made using piccisclv bulll scale modelsompact anechoic chamber, final proof of design testing require* the use of full scale vehicles and probably can only be done al an outdoor facility
The Soviets ate capable of constructing aindooi range roughly equivalent lo first-genera-lion US facilities With access lo Western technology, the Soviets probably will be able lo build indoor ranges in the neat fave years comparable to those currently in use in the United Stain f_
e have idenlified three outdoor ranges in the Soviet Union capable of preforming radar cross section measurements. The least active of these ranges Is al Aralskr_
hc range at Kalinin ha* probably been used to measure the radar cross section or several aerodynamic vehicles^
Sov,Ktj have over thc last five years upgraded then outdoor range at Voronezh!""
jThis range is environmentally suilcd
fc* low mill craa section measurements and. with further development, could de capable of rticasiiilog objects with even lower radar cross lections The Voronezh ranee ts our best candidate for further development of the advanced measurement capability necessary to support both counter-Stealth sensorand indigenous low signature and Stealth vehicle development programs^
ith lhc advent of cruise missiles withlow radar cross sections, the Soviets require sophisttcaled facilities capable of measuring the radar cross section of smaller targets In the past, such US ranges required carefully controlled, graded surfaces citcudmg over greatseveralwhkh precisely adjusted transmittal! bounce radar waves onto pylon-mounted targets lhat. In turn, reflect the energy into closely calibrated receiver aniennas No such Soviet ranges are known to eaisl Modern range-gating technique* have reduced the requirements for control of ground surfaces^
SO Achieving Stealth Is dependent on tbeol shaping and signature-reduction technologieseapon system We are aware that for years the Soviet* have applied some methods and techniques of signaturenotably radar returninfrared emission reduction, and lowof interceptsome of tbeir weapon SYSternv By combining these method* and techniques, thc Soviets couldow-signature flight vehicle, howi'ver. wc have no evidence thai Soviet designers have decidedonceptual approachtealth vehicle or thai integrated sieveloprneiit ol an offensive system is under way. They may rely on disclosures from the burgeoning US program to provide abasis for their indigenous efforts
SI Ne*ertireless, the Soviets haverasp of apiiheable design ihcory mid have shown sufheient interest in related research areas lo Indicate that ihey are developing some *Mtnalure-reduction technologies T
^Icad us to believe thai several independentare continuing.
rticles in Soviet technical publications Indicate an understanding ol radar cross section prediction and airframe-shaping techniques The Soviets haveeitertsivc research on radar-absorbingand haveide range of proven material* uiwn which their designers may draw.the newon of Soviet fighterscontainsoercent composite materials by weight, we have no information on live Soviet ap-ptoach lo the problem* posed by bonding and adhesive materials required to apply composite maleriablo airframe construction
ptimum shaping for low radar cross section could result in airframe* thai are marginally stable in flight The Soviets may be conducting ground-based rejiMtch in advanced automated flight controb and fly-by-wire concepts al lhe Novosibirsk Scientific In stilutc of Avialion
educing lhe radar and infrared signatures ofperformance turbine engines may well be the pacing factor in lhe development of any Stealth vehicle. Thc Soviets have used shielding lo reduce the IR signature of lhe engines on some of their attack hclicop-let* in reaction to the heat-seeking missile threat in Afghanistan, bui citeinal shielding of this lype tends lo increase lhe sire of radar returns While thev have also redesigned helicopter engine eihaust noiiles In an attempt loignatures, we arc no! aware ol any Soviet program to reduce the Infrared signatures of other lype* of aerodynamic vehicles
lic Soviets are progressing rapidly in several electronics fields associated with low-signature vehicle development* In lhe area of airbornelhe Soviets have lhe necessary Irschnology lo developransmitters These devicesby means of slmrt. high-powered bursts lhat reduce the likelihood ol an intercept lhal would give away lhc position of lhe host vehicle Spread spectrum communication* alsoigh potential forlo Steallh aircraft; we eapect lhe Soviet* to field an airborne spread spectrum system5
V Soviet* have sufficieni technological eiper-tise at hand lo satisfy thc passive navigationof Stealth vehicles Laser gyro equipment has been produced in the Soviet Union, and Soviet military author* have noted lheJS short range navigationid-look ing infrared, low light, level TV. and laser subsystems Protected improvements to lhe Soviet CLONASS space-based navigation system may be able In support Steallh operation*
The Soviets are alto progressing rapidly in radar technologies They have developed an electronically scanned phased-array antenna (or theox-houndlanar-array antenna for theainstay AW ACS aircraft. They probably willwideband signals and frequency agilityin order to reduce thc emission signatures ol their current airborne radars and meet theof Stealth vehicles. They have already fielded a
and narrow-band optical systems (laser rongelinders) in Iheulcrum.
he Soviets areew generation ofnd sea-launched cruise missiles designed inhal have reasonably low eiternaldial could be reduced through judiciousshaping and use of radar-absorbing materials.
accurate tracking of ballistic missiles,nd space systems. The Soviets may attempt to counter future US layered defenses by applying signalure-rcduclion techniques, many of which are equally applicable to aerodynamic,or space vehicles For example, theCommunity has assessed the SS-J8 follow-on
the pos.boost vehicle to carry 6i ,h*
lower sfenalure reentry vehicles and additional lh*
penetration aids and other counter-SDI devicesechni,,MO <hetlie longer term, thc Soviets also might
mcnt with tower signature propellants and may use other techniques to achieve range and pay load performance similar lo that of thehey also may use other signature-lowering techniques like radar-absorbing points and materials to reduce the vulnerability of iheir missiles and warheads to intercept.
he Soviets probably began to apply signa-ture-control techniques to ballistic missile reentry vehicles in lhef
an absorbingondueting layer located within the RV heal shield could reduce thc return signal; the magnitude of the reduction depends on lhe frequency of th. incideni radar and on lhe heat shield's dielectric ntoiierlres and configuiation of tlie conductive layer and heal shield materials. On the basts of thii analysis. conclude that the Soviets currently employ materials to modify (he radar cross sections of some of their reentry