I U S Al R FORCE PROJECT RAND RESEARCH MEMORANDUM POLARIS WF APOB SISJ l M l1 I P 011Ter October 28 1958 Thia 111aterial contain• Information affedlng the national defenM of th• United Statea within the 111-nlng of the o• plonoge laws TIii• 11 U S C Socs 793 and 794 the tran1111iaalon or the ronlation of which in any 111anner to an UflOuthorlHcl ponon 11 prohibited by •-· Assigned to _ _ _ _ _ _ _ _ _ _ __ This is a working paper Because it may be expanded modified or withdrawn at any time permission to quote or reproduce must be obtained from RAND The views conclusions and recommendations expressed herein do not necessarily reflect the official views or polici s of the United States Air Force DISTRIBUTION RESTRICTIONS Bot auitabl e tor clinribution to foreign aonrmenta or toreip na-t w•l •· Poec Regu r 'tli 41 0 4' 7· 2S -1 TMOD OF'TRANSMITIAL RE EIV ED FFOM A-A JD - ffi · r- ····r r 3r '- ' r r i l J5 ·' -9 L Jlot •u 11 able tor d1at ribut1on by the Anltcl Sem ces _ Teclm1e l ID tonation AgeDJJ7 AS IA Alltbority A1'R 205-i 3 · - · c ir t- i • •• r i r 1Jft re1trictions on Th i D L • · • o r Ci •· ' li' 'I •• L i l f -Jt ' • further distribution other 1 · · · · '-- _ ·'t'h'an those imposed by security regulations •• _ · • ' i J _sanc _ion ------- R nD jcc· ' ·· - 1 · • ' - i Ii wlH i l J --EXEi UBED FROM GOS •c_ BRlN1 _ _-____ ___ ACKROWLEDGMEN'l'S Appreciation is due the many st a ff members ot The RAM Corporation whose vork and counsel made the writing ot this Research Memorandum possi bl e The author would like to acknowledge 1n particular the assistance ot the t'olloving ind ivi dual a T F Burke E r c H s W 'W Kaufmann w I Rumer C L Freeman M A Margolis B L Shul man 1' A Banunian s s E R ZUbert R Eldridge Bettern Rowen C - - _ IM-23ll lo-28-58 - V SUMMARY This memorandum was written 1n esponse to interest within the Air Ste ff 1n a factual and unbiased assessment of the Polaris weapon system potential It is based on past work at RAND in the strategic area and on sped tic missile systems as well as on information obtained from the Polaris Special Projects Office and i ts contractors The time period ot prim r' y interest is pre- 1965 a period tor which U S strategic systems and torce structure may be hypothesized with reasonable certainty In this ccmtext the Polaria weapon system is approached u cme ot aeveral systems which improve our over-e ll deterrent posture and strategic capability- In today's world and tor the foreseeable future deterrence not only is a reaaOD ble philoso but should 'be our absolute first priority For our deterrent capability to be objective it must be designed tor the failure ot deterrence i e it muat function even if attacked b7 surprise in a well coordinated and detemined manner It 111WJt be inexorable without being infiexible 'Urtber in the design ot strategic torces it IIU8t be admitted that deterrence camiot be cert iD Dd there is a tini but incalculable probability- of general nuclear var It 1• in this environment that RAID bas looked at Polaris There is much to ccamend in Polaris u a part of the U S strategic torces Dispersal conceallllent and mobility are canbined to give this system a low order o-r vulnerability Tbe mobility- of Polaris in a MdilJII which tavors concealment rale out the poeaibility of the eDe'DQ' lmov1ng in advance the preciae geographical coordinate• of the force except tor the pa rt undergoing overhaul in port or being serviced at a tender The removal ot etrategic targets traa the U S or populated areas ao BM-23ll lo-28-58 vi tba t targeting this system does not result in collateral or bonus damage is also in favor of Pola ris although no attempt ha s been made to quantify this asset Polaris would be based forward so that under certain contingencies given reliable command and communications this system could have the shortest response time from command to weapon impact of any U S -delive ed weapons except for our overseas-based IRBM' s Moreover in the event of a premeditated enemy attack Polaris could have a useful wartime lif'e measured in weeks or months which under present plans no other strategic system would have against a coordinated ICJW and manned bcmber attack During the period o f' availability Polaris may also be the answer to adverse political develo lllents which would compromise our basing IRPM's in certain foreign countries Conceptuall y the Polaris system is interesting as a system with a low order of vulnerability to the expected enemy missile and manned b0111 ber threat and as a complement to the desired Air Force strategic posture which would include both a counterforce and counter-city strike capability How- ever as with all nev systems the aolutions to foreseeable technical problems and actual availability dates are to a significant degree uncertain Presently the first Polaris submarine is scheduled to be operational in October of' 19€o with missiles of 1000-n mi range which are designated A-1 The 150C -n mi missile designated the B lllOdel is scheduled to be operational in mid-1963 1 le ready-f'or--ee date for the first submarine is April 196o and for the ninth submarine February 1962 assuming FY-1959 The response time of Polaris and our overseas-based IRBM's would b comparable however REM basing is at present sort fixed and vulnerable to surprise attack I I U Co - · rir j fr f I RM-2311 1 8-58 Vii I f' tbe sixth through ninth submarines are not funded until FY-196o funding they will be delayed about eight months tor ea dates by six months Deployment dates lag the rea dy- The Polaris missile schedule is extremely tight and slippage will undoubtedly occur However the urgency ot the present situation warrants the e rfort being made by the Navy toward attaining early availability Technical considerations are discussed in Section II The critical areas at present appear to be particularly navigation fire control and communications they are su tticiently critical and important to warrant extreme effo -t by the Nav-y The guidance accuracy of the missile will be no better than the position and azimuth information supplied by the navigatio system and a failure of the fire control computer would put all sixteen missiles on a submarine out of commission For the early 1900's the Navy Yill depend primarily upon three highpower vr F JII' radio stations for transmission f'ram the U S are highly vulnerable to modest levels of overpressure These stations Even it they sur- vived they would probably suffer fran severe blackout in the event that high-altitude mega n shots were used by an en f'or communications disruption or by the u s f'or ICBM defense Plans should be tormulated for the use of azry and all applicable eammun1cation links including the SAC links and various relay schemes should be studied employing ships at sea many u s and overseas stations and aircraft including SAC alert banbers The problem ot communicating with Polaris submarines is compli ted by the tact that the submarine must be alerted or at least have pre-planned listening times in order to put up an antez ma to receive Therefore seismic equipnent on the submarine may be uaef'Ul as a bomb al l'm system 7 l trn ' iii I RM-2311 lo--28-59 viii For later periods the Navy is studying various communication systems such as sonar underwater cable nets meteor-burst techniques satellites etc The early A-1 missile design appears to be less critical from a tech- nical point of view However advances in the state-of-the-art are required for the B version which cannot yet be placed on a reliable timetable Although none of' these problems is 1 nsol uble more time developa ent and testing are required for a significantly better estimate of' performance and availability Under present plans Polaris submarines will operate from overseas tenders for a period of' two and a half' years and then return to the u s tor six months which includes four months in a shipyard and two months in training While in a State-side shipyard a submarine Vill undergo recoring of' the reactor depot-type maintenance and required modifications While over- seas a 9 lay cycle is planned With a submarine alongside its tender for 20-30 ya undergoing servicing and maintenance and on station or in transit to and from station for C0-70 days vith each crew lternate takina Two crews per submarine are planned 9 -day duty cycles The overseas-tender concept appears to offer the most effective and least costly mode of operations Based on the above concept and a 30-60-day cycle which also includes one-third of the nominal tender time being spent in training away trom the tender a Pol aris submarine would have an effectiveness ratio of 0 65 if' tenders were located in areas f'ran which targets could be reached Tbat is 65 per cent of the time submarines would be on station in transit to or from statio areas or near a tender on training maneuvers Excluding hllDIBll factors it appears technically feasible to keep two-thirds of the UNG UibflED 5 PoJ aris force essentially on station Hovever the psychological problems involved 1n keeping two crevs continuously on alternate 9 -day duty cycles on the same submarine for long periods are presently unknovn There appear to be two broad alterna tives open to the Soviet Union in countering the Polaris threat by killing the submarines 1 detecting and tracking submarines in peacetime with the intention ot kill ing them at the time ot a coordinated attack on other u s retaliatory forces and 2 locating submarines from patrol aircraft by detecting missiles during launch and in the first pa rt of their light followed by a rapid counterattack The problem of detecting and tracking any relatively quiet submarine is formidable even ignoring a f'1D l active attack that depends upon detection and tracking The ability of the nuclear-powered Polaris submarine to be quiet 1s a critical consideration in vulnerability and a strong ef'fort should be made in that direction This is not to say t bat the Soviet will not be able to take eftective action against the Polaris system but the characteristics of' the operating medium the state of' underwater detection technology and the available tactics favor the ender rather than the tracker it the Polaris submarine is quiet One scheme tor missile detection and anti-submarine attack is baaed on an airborne system using infrared search and radar ranging on the submarine-launched missile to-euri ace missiles are employed against the submarine Multiple air- A high probability- of kill appears tea sible Within five minutes of' an initial detection and • requires about fifty on tation aircra tt per million square miles there are also tactics available to counter such a system of Polaris is discussed in Section However The vulnerability v Excluding the Arctic Ocean neglecting wa ter vhicb the Soviet may UIHIGtflEu classify as their own such as the close-in Barents Sea Baltic Sea etc and considering only western launch e reas the l mi Polaris could hit 6o per cent or the 135 Soviet cities of 100 000 population and above while operating in an area o l 7 million square miles The 150o-mile missile coul d bit 87 per cent ot these cities while operating in n area of 3 6 million square miles · l i For the counter-city mission I three levels o damage were considered ranging tram at least 25 per cent to at least 75 per cent structural collapse Results tor the two limiting cases are summ rized in the follovi Ds table BUM ER OF WEAPONS REQUIBED ON TARGET FOR A GIVEN LEVEL AGAINST TBE 135 LARGEST sovmr CITIES ---t· i At 2 Structural Collapse 2 n mi CEP 4nmiCEP Least 135 r DAMAGE At Least 751 Structural Collapse 2 n mi CEP 4 nmiCEP 3 lio 48o 1200 135 150 290 135 135 200 I i 135 135 --·--------- --------l Do· b 3 I With a 2 mi CEP eight __ _ missiles on e t woulif 'be' required for a 90 per cent assurance level against a lo-psi target However against soft military targets whose coordinates are accuratel7 knovn Polaris missiles would be quite e f'tective -- r ·- 3 r__ r - -- -•-· • -- - t ·----------·-·- - - - - - -•-·- ----· ·-'_ _j RM-2311 1 8-58 xi - Target damage criteria are discussed in Section System costs tor Polaris re discussed in Section IV v For the present program consisting of nine submarines initial investment is estimated at 1256 2 millions and annual operating costs at 152 9 millions Assuming an etf'ectiveness ratio of' • 65 i e each submarine is able to tire missiles against targets 65 per cent of' the time the cost per missile for initial investment is 13 4 millions and the cost- per missile for annual operating costs is l 63 mil1ions The above costs do not include research and devel- opnent which has been estimated at 1040 millions • The growth potential of the present Polaris missile system is limited by the gecmetry of the launching tubes A significant increase in range beyond 1500 n mi with the present re-entry weight will be realized only by a new two-stage design utilizing a small increase in diameter which is available or utilizing longer launching tubes which are feasible A signifi- cant increase in yield will result only fran a significant increase in the yield-to-warhead-weight ratio A requirement tor increased missile range would seem to be primarily a function of submarine vulnerability Since the submarine is the pjor part of initial investment any design changes in the future that result in lower submarine cost can significantly decrease systems cost more study There are two outgrowths of the Polaris concept that deserve one 1s launching missiles f'r D sovn canisters and the other is the use of a submerged mobile barge as a missile base Although Polaris appears to be a reasonable and ef'f'ective ingredient of our strategic posture particularly in the countera ity deterrent role and against sott known military targets it by no means meets all the requirements of strategic capability Among other objectives besides RM 2311 l S-58 xii deterrence is the limiting of damage the u s vould receive 11 deterrence tailed an important element of which is a high-confidence counterforce capabUity made However the projection o'f requirements cannot be precisely The future as to the Soviet military posture operational capabilities and intent is extremely w icertain and the ways that a war might start run the gamut from the premeditated either well coordinated or poorly coordinated to one resulting 1 rom accidents mistakes miscalculations or sheer irrational expedience In the toreseeable future considering bot deterrence and the tact tbat deterrence is not certain there exists a requirement tor a protected 'force ot manned bombers vith multipl e weapons a search capa bil ity and termin l accuracy much superior to that of early generations of bal listic missiles This requirement is based on the expected soviet defense bard targets and targets vhose coordinates are onl v- known in a gross fashion There also exists the requirement tor ICBM1 s with warheads much larger than the Polaris warhead on the basis ot uncertainties and contingency planning The contin- gencies visualized are a future IC M defense requiring penetration aids increased v-ield and apcuracy against hard known targets and an defense program s u civil The larger warhead could be devoted to higher yield or higher yield plus penetration aids for both missile and manned--0omber penetration or And f'inal ly there eXists the requirement for a surtic ient number protected and dispersed del ivery vehicles not only to insure our capa- bility for the desired damage level against an enemy but also to make the job of destroying a significant fraction of our strategic 'force by an enemy infeasibly large 12 RM-2311 lo-28-58 Xiii Culf l Eltl S ACKNOWLEDGMEM'S • iii Section I II TECBNICAL S'l'A'l'E-OF-'tBE-AR'l' • • • • • • • A General SlJllll l r1 • • • • • • • • • • • • • B Propulsion and Perf'omance • • • C• Guid n ce • • • • • • • • • • • • • • • • • • • Bavigation and Fire Control System • • • • • • III CONCEPr OF OPERATIONS A Operational Plan ••• v Logistics • • • • • • • • • • Ef'f'ect of' Missile Bange • • • • • D Command and Co- unicationa • • • • • • COSTS • • EF'FEC' r'IVEll • A Vulnerability • • • • • • • • B Target Damage Criteria • • • • • • • • • • • C lfon-Collater l Damage • • • • • • • • • • Appendix Ccm parison of Sea -Based and Land-Based IRBM's D UN tttJ r' I l 5 5 6 9 10 13 13 14 15 16 21 25 25 Undersea Detection and ASW Weapon Ettectivenesa • • • • A Gu14ance • • • • • • • • • B coats c • B C D V THE POLARIS WEAPOll SYSTEM • D IV • • 41 46 47 51 57 71 l23 Ii I THE POLARIS WEAPON stSTEM · The present Polaris approach essentially reeulted tram the inc0111pa tib1lity of the Jupiter missile with the Nav r•s ultilaate aim tor a submarine missile system During the summer ot 1956 at the request ot the Chief ot Raval Operations the C011111littee tor Undereeaa Warfare ot the latioll l A c of Sciences con ducted a st°Ud1' program at Woods Role Maasachuaetta on the problems ot countering nuclear submarines which included a st ot the use of ballistic missiles 1D submarine strategic operation a In October ot 1956 the results ot this program at Woods Bole the ROBSICA report including the recammendation tor the developiaent of a twenty-to-thirty-- thouaandr-pound two-stage solid-propellant aubmarine- 1 armched ballistic Dlisaue were presented to Adm iral Burke and his staf't In November plans tor a small aol 1dr-i ropellant missile were reviewed by the Scientific Advisor Calllllittee to the Special Assistant to the Secretary ot Defense tor Guided Missiles In December the Department of Detenae approved a plan tor shitting the ettort frca the Jupiter program to the solid propellant l'f V Dlisaile syetem called Pol aria Therefore 1t may be stated that the Polaris program got underway at the begimling of 1957 In November 1957 the target date for achievement of the ultim te tactical missile was advanced frail 1965 to 1963 With an operatioJl81 capa bility beginning 1D 1960 Vith a missile of shorter range The Pol aria weapon system is baaed on survivability in the face ot a premeditated first attack thereby creating a degree ot objective deterrence However reli bl e c01111111D d control and caammication au st also surn ve For its low degree ot vulnerability Polaris relies on dispersal mobility and concealment BijrlSll l i C CIIBJl f 311 1 8-58 l 1 RESTRICTED DATA 2 1-----· ------·- ---- l s ATOMIC ENERGY ACT- 19114 L- - - - - ' - i -- -----·--- ---------- r p-• Length is 382 rt with a beam of 33 tt ·· - _ Sixteen missiles are stored in vertical launching tubes around the submarine• s center ot gravity The system is designed tor a ra te ot tire ot one missile per minute at the surrace or at 100-tt keel depth Ejection is by cc mpressed air The Polaris missile is a two-stage solid-propellant bal 1istic missile v 28 5 tt by 54 in weighing 28 6oo lb Guidance 1s inertial with a quoted 2-n mi CEP including the position error ot the sul aarine The tirst tactical miBSile A-J is schedul ed tor 196o With a nomjnaJ 1000-n mi range with a nom1nal The B version is scheduled tor early 1963 150 -n m1 range liaVigation Will be perf'oimed by a shipboard inertial navigation system SIBS which because ot g ro drif't requires periodic position tixes tor the desired missile accuracy SIRS supplies into mation to tbe tire control computer tor proper inputs to the missile and a lso supplies the mechanical optic l alignment system with an azimuth and a vertical 1n order to orient the guidance p1at1 orm Availability dates are shown 1n the tolloving tabl e traa the favy•s extended shipbuilding program Sllb lumber Ready-tor ea l 2 4-6o 7-00 3 l 5 6 l-61 4-61 7--61 Date Sub Number 7 DeplQJUnt dates Ready-tor-Sea Date l l 8 l -62 9 10 ll 12 2 4-62 5-62 13 7--62 8-62 25 9-63 J g the ready-tor• ea dates by eix months Only nine submarines bave been authorized by Congresa l1d tbe quoted avail ability dates tor submarines 6 through 9 are dependent upon FY-1959 funding If' these tour submarines are not f'tmded until FI-1960 an eight-month delay is estimated 311 10-28-58 5 A GERERAL SUMMARY Tbe present Polaris developaent program 1ncl u¥s tvo tactical versions ot the basic Polaris DLiasile con iguration and design with the Lockheed Missile Syateme Division as the prime contractor for the JILissile l eas guidance These are tbe tactical A-l and B missiles to provide an operation l capability 1n late 1960 vith sile range The A-1 is intended sacrifice 1n mis- '1'he Polaris B missile Vi th a tull range ot 1500 11 mi is currei rtJ y- programmed tor operational uae 1n mid-l 963 Thia development program further includes three types ot test missiles Vi th the same basic con t1gurat1on and general characteristics as the Polaris B missile The teat missiles are desigDated tbe AX A-J X and the BX The AX is a tull-4c le devel opnental misaile intended to test and develop the propulsive booster components and other missile caaponents 1n early tl 1ght The A lX is the test missile tor the tactic l A misalle and the BX serve• as the flight test vehicle tor the operational B missile Although not claasi- f'ied as a teat missile the early tactical A may also be considered as an operational test JILissile which can proVide operational factors tb t may be included 1n the B series o'f m issilea thereby increasing the potentialities ot the over-all weapon system The guidance system tor the Polaris missile is to be a l ightweight allinertial system weighing approximately 200 lb composed ot an 1 Dertial measure- ment unit a digital computer and associated electronics Its accuracy is to be ccmpatible vith an over- ll missile system accuracy o tvo siles maintenance concept now being conaidered ia replacement of the ccmplete system in case of ma i runction The The guidance system developunt 1a being pertormed by the MIT Inst mentation Laboratories as prime contractor The contract tor the producti011 ot the inertial guidance system ae well as the sutm rine-based system bu been awarded to General Electric The 'sms tire control sy-stem which is the basic inertial reference and navigation system on board the submarine is being bullt by Sperry However probably the tirst three submarines will use a Borth American Aviation system At present there are tour subcontrac- tors auppl y'ing the basic inertial components for the airborne system are Litton Minneapoli oneywell Kearfott and A c Sparkplug They All tour companies are building the same MIT signed SYrOB and integrating accelerometers ' be nuclear-powered submarine 1• of conservative design and ia some- what smaller than the Triton vhicb recently has been launched Production facilities for the Polaris submarine include the Electric Boat Com Ba'V Yard Mare Island Bavy Yard Portsmouth 1' B Bew York Ship at Bewport mews Virginia and Inga JJ• Ship at P aagoulaa Mi••· The following brief discussion will cover only maJor poiDta of the system design B PROPULSION AllD PBRFORMANCE The capabilities ot the test and tactical missile• will be largely detenllined by the propulsion system developDenta The AeroJet-General Corporation baa the respouibilit y tor these devel opaents The AX teat missile incorporates tested propellant• giviDg a ae -level specific ill pulse of 230 sec in a booster case made tram current mater1 la and by current man acturing techniques Except tor propellants the tactical A-1 and the A-lX m issilea require higher pertormanc• than is fail able -rra1 the current st te-ot-the tor production i tem aa represented by the AX components - - - BM-2311 10-28-58 __ 7 Currently the d evelopiaent program includes an advanced lightweight cue for the second stage ot the A-1 missile vith the tirat-etage case the same The lightveight case tor the second stage ot the A J as 1D the AX design missile is the eame case required tor the later B miaaile design The pro- pell Dta tor the A-1 missile are the same as those tor the AX m iaaile and represent current production availabilit y vith a apecitic impul se Eigher-i ertormance propellants ot 21fo-244 sec have been tested and a limited pro- duction ot this propel l D t could serve to increase the performance ot the A-l missile ot Polaris B propellants in the A-l second stage The use bas been suggested in order to ottset delays in obtaining the lightweight booster eaees W1tbout an excessive sacrifice ot range The lightweight caae design and the higher-energy propellants are both required in order to meet the Polaris B performance requirements ot warhead and range Recent teat• ot the Jetevator control system have proved the teasibUity ot this t ype ot control tor rocket boosters but the tests have also shown that a materi ls problem may exist i t higber-pertoniance propellallts are used i e higher exhaust gas temperature Higher-energy propellaZLta can be used i t research on materials acccmpaniea the d evelopaent ot the I propellallts Althollgh this discussion has centered on the devel oiaent ot propulsion caa ponents the design and ve18ht ot the guidance cClllponenta are important pe rameters in the pertomance ot the Polaris miaailea Perfonmmce is presently quoted With the tully operational and lightweight guidance system scheduled tor availability compatible with the 1960 operational date tor the A-l miselle current canponents ot inertial guidance heavier than the Polaris cC11Lponenta aa eetim ted - s t ' • 2i • -'· • • system are considerably Better eetimates tor the RM 3ll Ui ll U 10-28-58 RESTRICTED DATA 8 ATOMIC ENERGY ACT-19S4 guidance system cannot be made mtil complete unite are available ill early 1959 CUrrently the design of the A-1 tactical missile is Just pushing the state-of-the art ill materials fabricating metboda and inspection tecb- niquea while the B design ia just beyond current developnents However advances are required vbich camiot be placed on a reliable timetable and they provide a basis tor questionill8 specilic Polaris B perf'ormance and a-vailability Because ot geometrical design constraints imposed on the Polaris missile by the design of the launching system alternative solutions tor regaining performance in case of unforeseen technical ditticUlties are Range perf'ol ll Dce is pl'e e11 tly baaed on igm1naJ characteristics and estilllated weights and there is no reason to question the caJ cUlations made by Lockheed tor the quoted ranges ot the A-J and B missiles However a review ot other develbpaent programs as well e s canponent perfol'Dl Dce results in conservative estimates which degrade the quoted ill order to form an estimate ot the operational range maximtml ranges Such an estimate would illcl ucle the signilicant variations in rocket performance and weights and the operational envirorment e g rain The actaal operational range v1ll have to be determined by fiight teat A set of conservative estimates » m issUea A-l ot operatioll l ranges tor the A-l md is as tallows S00-1000 n mi With heavier than programmed guidance unit · SECRET RM 3ll lo-28-58 10 into account in determining the initial velocity- inputs 1 ntormation is obtained trom the SINS system The basic velocity- It is presently- planned to launch missiles with essentially no submarine velocity The thrust vector is to be controlled by- pos1t'ioning Jetevatora in the rocket exhaust The successf'ul developnent of' these Jetevators is a major problem area prilllarily because ot the high st1ction levels encountered due to the elevated temperature condition Jetevators have been used in the past in the Snark booster developnent but not tor the relatively- long burning times of' the Polaris motors which are of the order ot €o sec per stage It appears that stability- at staging may be a serious problem At staging the second stage is aero cally- unstable and until tbrust comes up there is no vay ot controlling the second stage Fins or a skirt could increase the stability- but this would add extra veight and drag Another problem is the possible collision ot the first stage with the second stage during the time the first stase thrust is dec 71ng and the second stage thrust is caning up These probl ems l so exist tor the Minuteman second stage in the high c preSBure reg lme Guidance is discussed turther in Appendix A D BAVIGATIOI AllD ll'IRE COlfl' ROL SYSTEM The sms sy-stem and the lire Control a ystem are by tar the most ccmplex parts ot the over-all system The SINS is a ahipb local-gravity- inertial s ystem whose purpose is to suppl y azimuth velocity and position 1 ntormation Thia information is sent to the tire control ccaputer so tbat it can compute and furnish proper initial condition settings proper values tor the airborne computer con11tants and the azimuth direction 'l'he SIBS system also supplies the alignment system via an optical system the direction of north - II i - 1tt lblitlU RM-23ll 10-28-58 9 RESTRICTED DATA ATOMIC ENERGY ACT l954 A-1 1000-1100 n mi with lightweight guidance azid lightweight second stage B l K 0-1500 n mi with lightweight cCDponents and the higherenergy propellant j--------------------------------- - 4k J ' ' i J ' --- -- C GUIDABCE - - - - --• _ - - w •·• _-_ - • - - - - - - ·- - _ ___ __J The guidance f'or the Polaris aissile is a velocity-to-4 ained scheme developed orig SnaJJy at Ml' f'or the Thor mi• aue f'or an IR BM guidance sy-atem It is an excellent scheme Integrals ot thrust and 11ft accel erations are digital inputs into an airborne digital computer erometers in the inertial measurement unit f'l Clll the integrating accel- The iDitial velocity- conditions are set in by- the aubiaarine--baaed f'ire control eyatem The airborne computer solves a set ot guidance equations and regulates tbru at cutoff and aupplies the proper steering • ignal 1 There are eight preselected targets tor the sixteen missiles on board the submarine centers or For theee eight target points and f'or launch points in the 20-n mi x 20-n mi grids 1 preccaputed inputs to the guidance ·e qua-- tiona and the azimuth direction are stored on cards The fire control com- puter interpolates these values to obtain the proper settings tor the exact launch point In this calculation the velocity ot the submarine is taken 1 i · -- If' u lrt· 1 •l J ·l JI · l f V r- A F'I · F - FiI ° i RM--23 ll l0--28-58 ll and the vertical so tbat the platform can be oriented tor correcting the drit't ot the gyros ill the sms The present concept system is either by cel es- tial illf'ormation obtained from star trackers or by position tixes obtained f'rom bottClll maps There is acme question as to how often clouds Will the stars so that cel estial tixea c m1ot be made a obscure Also there is some queation to how much ot the ocean bottaa in the intended areas of operation Will be mapped One ot the problems in using underwater maps is that an active emanating system muat be used tor an appreciable interval sms ot time In order to correct tor both position and azimuth more tbal1 one fix is required Possible en effort directed tovard detection tracking and active defense c m1ot be discounted tor the tuture Therefore critical situations can be imagined when the submarine needed a tix and Yi shed to remain quiet Position and azimuth are so important to the Polaris system that much effort should be expended in this area during the early system developaent period An addi- tional capability would result traa designing the stellar optical system to also sight 011 surveyed landmarks and lights The tire control system 1• a ver ccnplex one It muet calculate and supply initial conditiona guidance constants azimuth direction and velocity correction• tor erection ot the inertial platform to siXteen missiles under constantly- changing conditions The rel iability of such a system seema to be quite a problem and a allure of the tire control ccaputer would put l l sixteen missiles out o t cCllllldaeion Many ot· the problems are relieved by the submarine sitting quietly on the bottom with locked gilllb l s where poseibl e particularly in areaa or under weather conditions when corrections to impossible to obtain sms IILight be di tticult or ' - r ' I - • - · --- J -- _ l - - - ' - 1'· 1· J - _ 1 1 l RM-2311 10- 8-58 13 III A CONCEPr OP OPERATIONS OPERATIONAL PLAN Under present plans Polaris submarines will Op r te tram overseas tenders tor a period ot two and a years and then return to the u s tor six 11011ths which includes tour months 1n a shipyard ud two months 1n training While in a State-eide shipyard a submarine will undergo recoring ot the reactor depot-type mainteD Uce and required mcditic tions While over- seas a 90-day cycle is pl anned with a submarine alongside its tender for 13 to 20 days undergoing servicing and maintenance in training away tram the tender for 7 to 10 days and on station or in trausit to and trom for 6 to 70 days Two crews per nate 90-da7 duty cycles The overseas tender concept appears to otter the moat effective and least costJ y mode ot operations It vOUld also appear reasonable to station tenders ill areas trom which targets could be reached U the more conserva- tive overseas cycle is as111J11ed tbe ettectiveneaa ratio tor the force is o 65 That is two-thirds ot the t lllle the submarines are oYeraeaa away tran a tend er and thdretore possibly unta rgetable It the tender time could be cut to 13 days and the time ill the U S to 3 months the ef'fectiveneaa ratio would be increased to o 80 It appears technic lly feasible to reach an ef'tectiveneaa ratio around o 6 or o 65 however there may be psycho- logical problem a involved 1n two crews cont1DU l ly t-ak1Dg alternate 90-ds 7 duty cycles on the same submarine for two and a halt years For a given support level the coat ot the a7stem varies inversely With this ratio If the support levels are tixed an increase in etfectiveneae ratio trail 0 5 to O 7 would result 1n 40 per cent decrease in order to do the aame Job 1n coets or t'orce requirements ' 3ll lo-28-58 14 When the torce size is large enough to require several tenders the tenders can be located so tbat the submarines vould bave a target coverage capability 1n transit to and trom their on-station areas Under this con- cept the f'orce could have the fastest response time of' any protected str tegic system proposed to date The t'WO-Wek transit time to and f'rom the u s out of' three years is 1 nsign1f'1cant amounting to only l 4- per cent B LOGISTICS In a pa per distributed by the Chief' ot naval Operations entitled The Ravy ot the 1970 Era 50 misaUe submarines are allocated to the strategic miHion This f'orce includes about 11 submarines vith the tiDal version ot the Polaris ballistic missile and about 10 IDl l ler submarines Yi th later-generation miBBilea cl aasif'ied as very precise which could also be used tor tactical purpoees Taking a f'orce of' 50 submarines as an example and assuming a 30 to 60-day cycle overseas with tvo submarines per tender and a 6-month shipyard time per t hree yea rs vith the tull 30 days or 6 months epent alongside the tender or 1n the shipyard 7 tenders and 9 drydock spaces would be required I one-third of the J ian1 naJ shipyard or tender times were spent in training 111 open waters then 5 tenders and 6 docks YOUl d be required Further if' a tender serviced 3 submarines instead of' 2 only 3 tenders vould be reqtlll'ed It multiple drydocks per yard were employed then points to be supplied are turther reduced The tenders are small shipyards and are tran a mainten- ance standpoint excluding re-euppl y eHenti ll y ael '-eutticient From this brief' exercise it appears that the logistic requirements the Polaris system are modest tor Five tenders and 3 shipyards and 2 drydocks per yard could support a torce ot 50 aubllarines Two missile depots one RM-2311 8-58 15 on each coast Dlight be desirable in order to tacilitate the tlov of materials Since ve do not have a Navy Logistic Plan we can hypothesize ll waii supporting the Paci fic force thus saving 4500 n mi and tvo points on the East coast supporting the Atlantic force One or two tend ere tor the Pacitic and three or tour tor the Atlantic would be sutticient For the torce used 1n this example the tlov ot materials would be trail the factories to 2 depots to 3 yards to 4 or 5 tenders C EttL- r OF MISSILE RANGE In order to get an appreciation ot the target coverage tor the early missiles and al so the effect of missile _range on target coverage the following nine missile la'ODch points were ass'Ullled as being fairly reasonable A - ott southern coast ot Spitzbergen B - oft northern Borwegian coast - vicinity ot Trauo C - ott southern forwegj an coaat - vicinity ot Bergen D - Tyrrhenian Sea - vicin ity of Genoa E - Northern Aegean Sea - vicinity or Sal onika F - off southern coast of Turkey - vicinity ot Antal ya G - Persian Gul t' B - Arabian Sea - vicinity ot Karachi I - oft southern coast ot Hokkaido Japan The ability to hit the 135 cities of at least 100 000 population in the vaa considered using missile ranges ot 1000 and 1500 n mi s u The only cri- terion was range missile per f'ormance reli bilit7 etc were not taken into consideration The total population of these 135 cities was estimated to be appro%im tely 43 million in the early 19€ic •s ' he f'olloving table shows the target coverage ror the assumed launching points tor a missile · range l _ siiifir t ' • I 1 3ll 10 8-58 16 Launch Point Jumber ot Cities Within Range A 3 21 B C D E 14 14 F 50 50 G 10 H 4 I 4 Population thousands 610 ll 653 l0 1428 3 766 12 124 l2 778 2 612 1 008 9 30 ApproXimately l o per cent ot the tirst ranking cities cannot be hit with a The total population ot the 82 cities included in the 1000 n mi aiasile above table is 30 o million With a missile ot 150 Mi mi range the following data apply Launch Point Bumber ot Cities Within Itange 67 86 78 A B C D 72 E 89 94 J' G 55 14 H I 6 Population thouaanda 16 308 28 209 25 1424 23 219 28 677 30 346 13 689 3 581 1 225 Approximately 12 5 per cent ot the first 1'N k1ng cities cannot be hit vith a 150 - n mi missile The total population ot the 119 cities incl uded in the above table is 38 8 million Fran these tables it is evident that 1n the initial st 6es ot opera- tiona 1 e tev Pol aria submarines available the most advantageous areas tor launching mi 1iles to hit cities ia the Mediterranean sea points E and F followed by points Band Cott the Norwegian coast D COMMAND AND CO l U f ICA l'IONS b-2311 10-28-58 17 ot comrn•n control and cCllllllunication tter the event ot a soviet surprise attack It is important to understand that al though the submarines at sea are mobile their command and control and much ot their communications are not If' ccmmnications are so disrupted that retaiiation is delayed by days and is uncoordinated then the ettects ot this retaliation could be veil below the expected level if the enemy bad active defense against re-entry bodies had an ASW capability against the Polaris submarine and evacuated people trwl maJor cities The cbaraeteriatica such as mobil1ty conce J ment and dispersal in overseas waters that give the Polaris submarine a low order ot vulnerability also make the system very ditf'icult to control particularly und Jllr a coordiDated surprise attack on this cot111try- and overseas strategic facilities However it the Pol aria syatem can be controlled and coordinated even though c011111llmications are delayed many hours the syatem would retain a significant capability pa rti cularly- it the vulnerability reaponae and posture ot the ZI-baaed atrategic torces were adequatel 7 improved In this case the DLixed and diversitied strategic torces would aupent each other and result 1D a better capability tor both deterrences and cOU11tertorce In tact the aituation can be imagined where Polaris vould have a aignilieant value over days or weeka including a negotiable value tor bringing a war to a conclusion The syatem that would be desirable is one that could alert the submarines and transmit orders reliably ill a matter ot minutes gencie• where rapid response would be There are aaae contill- extreme value However such system is extremely- ditticult to obtain it the enemy does not cooperate For the earl y 19601 • the f r f' v1ll depend primarily upon three highpower VI 3 FJF radio station• tor tr llamia11on trca the Annapolla MarylaDd u s One is located at and a third v1l l U IUWflED RESTRICTED DATA ATOMIC ENERGY ACT- 1954 be located in Maine to be operational in late 196o VLF and BF 11 - i l -- - vw _erabl - _ • 9' - t ti' T oC I 'c i - I i l i I cords tram ionospheric sounders at dispersed ground location aud airborne sounders tlovn through the surrounding areas indicated that an intense arti tici l ionosphere was created al moat instantaneously at about 35 to e altitude observed to extend to distances ot 800 miles or more - was ---- --------·· 1 1 -- - -- ·_______ _ ______ Thia layer trom the shot area I I ' I I •-·- ----___ ·----------- ·· ___ ··---- ------- I'Thia -- ionization decayed after 20 minutes or ao suft1cient1y to l lov ma ny Hawaiian c1rcUita to be restored However a second and even more intense radio black- out period was observed at Havaii shortly therea rter several hours atter shot time his one lasted tor Larger weapons or weapons specitic lly de- signed to produce absorption and burst at perhaps more optiJDal altitudes cotJld produce more intense and prolonged ettecta than those observed tor these shots There are also the possibilities that veapons detonated at about 100 or 200-mile a l titude may cause signal interf'erences extendillg to higher radio frequencies or that other types ot weapon may eventual ly prove et rective 1n produci Dg high-intensity background noise in the 1-mega cycle to 100-megacycle portion of the spectrum ijlG·w· r ' nrc ' t tf •· • • RM-2311 10-28-58 19 The approach that the Ilavy is presentl y taking for the early time period before new developments will be avail able is quite reasonable This approach considers the use of depth charges which could be delivered by missiles1 in order to a lert submarines to surface an antenna for'receipt of ordersjand the use of various relay schemes The problems involved appear to be those of preplanning and procedures rather than of technical developments After an attack that the Soviet might launch against the U S and overseas facilities a tremendous amount of connnunications equipment in the U S at sea and in friendly countries would survive due to sheer numbers With intelligent pre- planning of procedures relative t o various contingencies communications could be quite reliable The preplanning should include the use of any and all equipment that might have a capability rather than a few best approaches Even hardened multiple terminals on the transatlantic cable may be interesting In such an environment the control of the strategic and defensive forces would be of singular importance In order t o alert the submarine force the use of seismic equipment in submarines might be applicable as a bomb ala rm system The only backup for various alert schemes would be preplanned listening times For later periods the Navy is interested in such schemes of connnunicating as sonar underwater cable nets meteor-burst techniques communications satellites etc development support All of these schemes should receive research and Reliable communications are basic to all weapon sys- teins and especially to mobile systems IV COSTS These prelim1Dary cost estimates of' the Po1aris Weapon System are based on both 1nton1ation obtained f'rom the Navy and RAM estillates of' the unknowns r However they are not to be considered as either precise or f'inal The Special Projects O 'f'ice has been quite cooperative in mak1ng available intormation known to them However there remain areaa of' ucertainty Therefore the usual admonitions pertaining to cost estimates in general apply Cost data obtailled from the Navy pertain to nine submarines and one tender although uncertainty exists as to the nlDDber of' submarines tbat will be in the prelim Jnary program Congress bas appropri ted tunds tor six nuclear-powered Polaris submarines in the Fiscal Year 1959 program This is in addition to tbe three funded inn 1958 and currently uder construction Construction of' an additional tvo submarines bas been approved so that five submarines are definitely in the works However the additional funds P- propriated by Congress tor the additional tour submarines bave not been allocated It is anticipated tbat when it next convenes Congress will exert c onsiderabl e pressure on the Administration to release the f'unds The Bavy meanwhile is thinking in tems of n1m submarines and it is on this basis that the costs estimates are made The plan of' operations for the submarines and tender bas been outl ined One tender is still contemplated for nine submarines which Navy personnel f'eel is adequate However there are plans ror an additional tender speci ri- cal l y designed to support Pol aria submarines Constro ction coats ror this a dd1tionaJ tender are estimated at sixty-one million dollars Each submarine will bave sixteen missiles on board plus an additional sixteen on the tender sE·c1tf ·'- 1 ' r•rK· Table l on the following page lists the initial investment and annnal operating costs by item tollowing the RAND Cost Analysis Department tormat These costs are based chiefly on the figures obtained trcm the Special Projects Ottice and the implications ot these figures A discussion or these costs is given in Appendix B RM-23ll lo-28-58 23 Table l POLARIS WEAPONS SYSTF M - REVISED cosTS NIHE sUBMARms Amounts in millions of dollars Initial Investment Item Installations Base Facilities Training Facilities Amlua l Operating 10 0 o 4 - Base Maintenance Equipnen1 Submarines Missile Latlllching and Control System Equip11ent Tender Tender Equipnent Missiles 16o Missile Containers Base Equipaent Training Equipnent Stocks Initial Stocks and Readiness Reserves Initial Spares missiles only Initial Spares shipboard FBM Transportation Personnel 'l'r inillg Pay and Allowances Travel • 3 4 900 0 26 0 43 2 o 6 171 2 28 9 7 0 1 6 l 3 l l a 1 5 9 o a 10 1 4 o o 4 14 5 0 1 Maintenance and Fuel Submarines Tender Services and Miscellaneous Command and Major Support Camnand Administration TOTAL It Interim Camnunications are added Facilities Equipnent TOTAL Per Submarine Per Missile Research and Developnent 20 2 1203 6 149 9 46 2 2 3 6 4 1256 2 139 6 8 7 1 06 1040 o 2296 • 2 A more 7 152 9 17 0 152 9 detailed analysis of tbese costs is given 1n Appendix B RM-23ll l0-28-58 25 V EFFECTIVENESS The principal characteristic of' the Polaris s stem tbat distinguishes it from other strategic bombardment systems now planned tor the l900 1 s is 1ts ability to move continuously in a medium which tavora concealment movement may This rale out the possibility ot the enemy knowing in advance the precise geographical coordinates tor this torce except for the part ot it undergoing overhaul 1n port or being serviced at a tender It is hoped that the system will be little vulnerable to surprise atanic attacks and less cautious comments suggest tbat the system will be invulnerable However 1t would appear tbat the submarine is not inherently invulnerable The real question is what can the SoViet Union do to counter the Polaris threat and how much ettort might it take It must be assumed tbat the Soviet Union will work bard at countering this 117stea Since the Polaris Will ccme into operation 1n a period when the Soviet Union is expected to be able to send large numbers ot missiles against the U s with 11ttle or no warning backed up by manned bombers the attention focused by the Navy- on the probl em of surviVing enemy attacks 1n the design of this system is clear warranted and it is this aspect ot the sy-stem that is its chief' virtue However while peacetime movement and concealment are usetul virtues they are neither nece 88 lY nor sufficient 1n order to be able to strike back It is erroneous to regard e tixed system as vulnerable and a mobile system as invulnerable For exaap le the U S baa plans tor fixed bard dispersed bases able to vithataDd heavy thermonuclear missile attacks while on the other band a tew mobile aircraft carriers in a limited area near an enemy represent targets nearl y as vulnerable aa soft fixed bases RM 3ll lo-28-58 26 to a premeditated surprise attack There appear to be two broad alternatives open to the Soviet Union in counteri Dg the Polaris threat by killing the submarines l detecting 8 lld tracking submarines in peacetime with the intention ot killing them at the time ot coordinated attack on other U S retaliatory forces and 2 locating submarines tran pe trol aircraft or ships by detecting missiles during launch nd 1n the tirst pa rt ot flight followed by a rapid counter- attack Submarine Detection and Anti-Submarine Attack This section considers the more typic l undersea warfare methods which the Soviet Union al1 ght employ 1n defense against a retaliato17 attack by Throughout the field ot undersea war- subrlarine-launched Polaris missiles fare which is as broad and c011pl ex as the field ot air vartare underwater sound devices are the counterparts ot radars in air warfare and they are Just as important 1n determining the characteristics and capabilities ot weapon systems However -anderwater sound deVices generally work very poorly com l Nd vith their radar counterparts This tact tends to give the intrud- ing submarine a relatj vely greater advantage than an intruding aircraft On the whole the two fields are about nen as tar aa technical develo ment and basic underatanding ot the sic l processes are concerned There is ot course Rad are tbe possibility that attempts might be made to kill our submarines in peacetime especially it this could be done 1n a way unl ikely to give positive evidence ot the attack i e it the only evidence we vould get is the failure ot our submarine to return to b ae Thia might happen it ve vere to attempt to operate 1n an area regarded by the Russians as a private preserve Perhaps more likely would be an attack on submarines 1n retaliation tor some objectionable u s move For example there have been propoa l s in DOD that the U S sink SoViet submarines th t approach too near our coasts If ve were to adopt such a policy ve should expect tbat same of our Polaris submarines would tail to return to base In tact a truly l imited va r can be imagined which ia limited to submarines and only a tew submarines - -· n 11 _·j • v IJK · 1' · r r· aui - E 1 r I • r are tar more numerous more varied and more camonpl ace but these di t terencea do not indicate a corresponding ditf'erence in understanding On the whole pretty fair guesses can be made as to the evolutionary course which radar v1ll take at least the future 1a planned on' this baaia and that is really the iaportant point tor this discuaaion In sonar at least among tho• e who are not familiar Vith the aubJect there 1a sometilles an inclination to think that matters are di tterent Thia view amounts to a denial ot tbe present understanding ot the t1eld it is an mivillingneas to plan tor the tuture on the b sia ot vbat 11 actually known it is nearly- a hope that a miraculous cure Vill dispel unpleasant re lity It is unwarranted The main avenue• long which aonar improvement can be expected have been clear tor years and developzient is proceeding down them higher radiated power better radiation patterns lover frequencies bigger arrays improved signal proce•• ing As ¥1th radar more data are needed on long e propagation espec over-the-horizon etfects and long-range clutter Hovever one can make tair eatilllates ot the illlprovementa to be expected from a given effort It is the ocean not Just the engineering skill which sets the iaita and the price OD pertonumce ID both rad r and sonar the question is not really whether a maJor nation baa the technical lmov-hov to obtain a certain capability instead whether the nation chooses to pay the price It is Just as a • ut'ficientl y numerous assortment of radars could be uaed to track small lov-tlying aircraft anywhere in the u s so too a sufficiently numerous usortment ot sonars aould track a submarine anywhere in the ocean The coat ot aueh radar aoverage is aatronomic l so is the coat of the sonar ooTerage It is not possible to give a concise caver to the question ot what · r e sonars C D achieve It 1a Jlecesaary to break the answer '' down into at BM-2311 lo-2 58 28 leaat a tev ditterent caaea Besides the nature ot the sonar 1taelt the tolloving variabl es intluence the anaver strongly - kind ot sonar pl trorm - 1peed of aonar plaUorm - depth at vhich radiator 1a placed -vater depth to bottan - depth ot target - temperature structure - character ot the bottan There are caabinatiODa ot these variables tor which the sonar range ia as littl e as 100 yards and there are other• tor whi ch ve hope to achieve 100 miles 1n future equipaent Capabilities ot u s An average is easentially mean1llgl ess Active Sonar The estimates presented bel ov ot present and anticipated active sonar ce pabilities are taken entirely troa a report prepared during 1 956 and pub- lished during 1957 by the CClllmittee on Undersea war-ta re ot the Rational Research Council However additional eamunts and intomation are included vhich are based i l l on a aeries ot recent viaita to Davy agencies including OpNav BuShipa USBUSL mu and usm The active ranges presented are thoae tor 50 per cent probability ot detection ot a randcm-e spect aubm rine at 14 db target atrengtb and are baaed on the toll owing aet ot atandard conditions unleBS otherwise noted Peterson s A Expected Active and Passive Sonar Detection Capabilities ot Current and Future Plat oria-lquipment cc ibiiiatlona NRC CUW 0241 April 1957 Secret I RM 3ll lo-28-58 29 o Deep water 2500 fathoms convergence zone path8 exist o Mixed aurtace-layer depth ot lOO tt o Surface temperature of o Sea state 50° r 2 This situation represents an approximate average ot conditions tor the middle Borth Atlantic over the spring summer and ta ll periods During the winter the miXed l r depth increases to depths greater than 300 tt because ot the higher wind torces and concomitantly higher sea states With ASW 1urtace ships at about 15 mots or less estimated ranges tor equipnent dependent upon transmission paths near the s'Ul'i'ace vary tram 2 to 12 n m 1 against a submarine in the layer and trcm l to 3 n mi tor a sub- marine below the l r The higher value tor the submarine bel ow the layer depends upon the surface ship carrying a sonar radiator which can be put below the layer The higher values tor a submarine in the layer show the anticipated bezletita ot low frequency and high power but the intluence of It mat be emphasized that the l 2-11 mi estimate the layer is evident even though by surtace paths 1a t o r water For equipnent uaing the convergence zone estimates vary trom 25 to €ion mi dependent upon surtace retlection loss For bottan reflection paths ranges var trom 5 to 15 n mi dependent upon bottam characteristics Surtace ship• which move about at high speed are v1rtual ly useless aa compared with slower ships tbe c urftS ot sel1 -11oise versus speed climb astronomic lly above about 18 knots and there is no present reason to toresee much change in this situation Renee s u must obtain search rate by numbers and not by speed ·1 surface search forces RM-2311 c -·· · l 'sE · ' ' R 1t Elf H · 1 -_1 l0-28-58 30 'With airborne eqUipnent using dipped aona r at speeds f'rom 10 to 35 knots estimated ranges vary f'rom 1 5 to 7 n mi against a submarine in the layer a nd from l to 2 n mi f'or a submarine below the layer However these aircraft move slowly 1n terms of the distances involved and in terms ot the speed with which a submarine can break off sonar contact hence such craft require basing rather close to the operating area As things stand today the s u does not have such bases near the potential Polaris operatini areas except tor the Barents Sea The appearance in the Russian tleet of numerous small air- craft carriers would probably signal the developnent of' such basing capability for the Norwegian Sea In any event such sonars are intrinsically limited by the weight size and power capabilities of the platto nn and so cannot be expected to show great range improvement in the f'oreseeable future Expl osive echo-ranging has not lived up ruJJ y to the expectations of a f'w years ago and ranges are estimated between l 2 and 5 n mi Inasmuch as an expl oeive source denies the use ot some valmbJ e signal processing schemes 1n the receiver this is perhaps not surprising With a submarine pl atf'o nn ranges var from l to 10 n mi dependent upon whether the tracker is noisy or quiet and whether the target is in the layer or bel ov it However the submarine can dive 1n and out of the tbel'm l structure as his target does it nucl ear it can m 11euver and speed up so as to remain on the tail of' the target To do these things the pursuing submarine must use active sonar and so is vulnerable to attack himself but at least he cannot so readily be shaken off' the trail Except tor the tact that these values pertain to deep water onJ y tbese estimates are probably the most conservative of any given in the NRC report On the whole the estimates presented are more rel evant to the classic _fl - · s ecRn JI I t • RM- 3ll 10-28-58 31 anti• ubmarine war in defense ot overseas transport than to defense against Polaris Tvo factors particularly lead to this camment the choice ot water depth and sonar conditions and the presentation of' 50 per cent r probabi 11ty' ranges The contemplated use ot Polaris undoubtedly involves operation in the 11orth Sea along the Norwegian Coast and possibly in the Ba rents sea All these waters are shallower mostly about 100 tathcas rather than 2500 tathClll 8 and the temperature structure is probably poorer th n that assumed in the NRC report The HRC estimates tor long ranges by reconvergence or b y deep -water bottan bounce are inapplicable in shallow water Even the estimates ot ranges by near• urface paths are on the opt1m ist1c side in these shallow waters because ot temperature structure and bottom rever- beration l itty per cent probability detection ranges are usetul but they are perhaps more indicative ot the operatioD l problem in a protracted war ot attrition than in a sudden-death all-out strategic nuc lear va r 50 per cent probability ranges should be supplemented because by The 90 per cent ' probability ranges such high values J10re nearly characterize the problem faced by the defenders Because ot temperature and bottom condi- tions it is not uncCIIIIWn to encomter 50 per cent probability ranges of one or two klloyards and 90 per cent probability ranges ot zero yards That is in many sbalJ ov water areas the defending torces especial l y surface ships and shall av dtmked sonars may- never have 90 per cent probsbility of detection because ot temperature structure and bottom conditiona RM-2311 l0 B-58 32 ···--· The NRC report data also tacitly assume that the· submarilief f'alls- 'to ·- execute some of the evasive maneuvers which a Polaris nuclear b a t could and probably vould use Aside from countermeasures the boat can turn tail aspect on his pursuer thereby reducing his echo some four or more db below the value assumed here and knocking the bottom out of 90 per cent ranges for many equipments Further the boat can reduce speed to very tew knots thereby nearly el1minating the doppler differentie l whereby tbe ASW vessel seeks to sort him out from the reverberation In shallow seas up to per- haps 200 fathoms the boat can simply lie on the bottom To discriminate the boat from other objects on the bottom ther becomes very difficult if the bottom is at all rough and rocky the boat blends in and only a highresolution map of the bottom can disclose the boat by its sllape Finally if the defender is not well equipped vi th low-frequency passive sonar in the combat area a nuclear submarine can it' he chooses simply run away from surface ASW forces These latter vessels cannot make better than about 15 knots vithout sacrificing detection rmge seriously The nuclear boat can easily afford to go faster if he is reasonably sure he wi ll not be tracked on passive gep r Capabilities of U s Passive Sonar In recent years the great hope tor the ASW problem has been passive sonar that is lov- f'requency listening equipment in deep water to hear the noise radiated by submarines By using long lines ot rather simple receiving units it is possible to obtain considerable directivity even at J ow frequencies e g 100 cps Tbe numerous receivers are strung along multi-conductor cable so that each output is brought separately to the beach There phasing netvorks are used to make steerable beams or groups · -· _ RM- 311 l0- 8-58 3 3 of fixed beams from a single array o-r hydrophones Bearing accuracy o-r 2 - degrees at wavelengths of 50 ft is typical of the performance for existing gear By triangulation tvo such arrays can now yield a position fix with typical accuracy of about 4 miles radius this is good enough for surface active sonar to finish the job with a modest amount of search By using low frequency such shore-based deep listening arrays can achieve detection and tracking at ranges of hundreds of miles because of low attenuation a nd duct propagation in the deep sound channel It is important to observe that it is only in deep water that such long ranges can be achieved In shallower waters bottom absorption and multiple scat- tering reduce the range drastically Much the same techniques which are used in deep-water bottom-mo ted arrays can be used in shall ow water and in smaller arrays carried aboe rd ships notably submarines In shallow water as noted above ra naes are perforce less under otherwise similar conditions Ranges in ship-mounted gear are also less partly because of interference from mm ship noise but also because the array is smaller Much effort is now devoted to quieting the new attack submartnes sc as to improve their listening ranges however it should always be possible tor bigger bottom-mounted arrays to give appreciably longer range The listening a rra ys which can yield such long ranges against snorkeling submarines can yield comparably great ranges against noisy nuclear boats e g Nautilus • Furthermore the ra nges are quite long against high-speed boa ts even i they are otherwise fairly quiet But ase inst slow boats and against slow quiet nuclear boats the passive detection ranges fall to values comparable to active sonar range or even less For the foregoing reason the vulnerability of the Polaris weapon system RM-23ll 10-28-58 34 lr 1 1 be critically dependent upon the ability of the submarine to be quiet This is probably the most critical factor in the whole problem of Polaris vulnerability because the S U will not find it difficult to track noisy boats On tbe other hand they will find it very difficult to detect quiet boats For a submarine platform at slow speeds detection ranges against a snorkeling or cavitating target are estimated to be as much as 90 n mi for certain equipment vhile an increase in speed of the platform to about 13 knots decreases the detection range by a factor of 10 and more If the target is quiet at low speed then detection ra Dges are low--of' the order of 5 n mi or less For shore-based deep arrays detection rariges ve ry from values of 200 to 1000 n mi against a high-speed noisy nuclear boat such as the Nautilus to t to 5 n mi against a quiet battery boat or possibly a quiet nuclear boat at lov speed Shallow-water s are estimated to give detection ranges of 20 to 50 n mi against snorkelillg boats and l to 10 n mi against quiet boats Sonar Countermeasures Although e ll sorts of active and passive sonar countermeasures vere employed during WW n it is only rarely tha t one finds countermeasures brought into a discussion of the potentialities o a sonar weapon system In this respect the vhole field of sonar is less advanced than radar where a universal consciousness of countermeasures exists Not that the techniques and devices for sonar countermeasures a re lacking rather the absence of this phase of the problem from sonar system analyses sanetimes lends a n air of unrealistic optimism to forecasts of capability against a skilled and ' -· I Sl ltiET 1 •• 1 ·n - -·· ' ' ' U lfit U 311 10-28-58 35 determined enemy Polaris submarines could derive much protection from well used countermeasures they should be incorporated in the weapon system and they shoul d be accounted tor 1n an estimate of vulnerability There are several techniques and devices which can help a submarine avoid detection entirely be quiet Probably the most important of all is simply to However even the quietest boat f'aces some sma 11 chance of being found more or less by accident One wa y to dim1nish this chance markedly is by painting the submarine with a sound-absorbing coating During WW n the German Navy developed absorbing coatings there is some controversy over their actual effectiveness and over the absorption mechanism in the material but there seems 11ttle doubt that some absorption was obtained In this connection it must be empbasized that as little as 3-db echo reduction ca n have drastic e ff'ects on detection probability especially 1n shallow water where reverberation limits the detection raJJge severely The old NAC and NAE beacons and their various kin are sonar noise- makers which a submarine can eject to Jam enemy sonar parts of radar noise and sweep Jamners They work 'l'hey are the counter- to some degree and help a submarine to breakioff sonar contact once bis presence in the area 1s known To work against the new high-power low-frequency sollal s bigger and more costly devices would be needed Such a development is certainly possible its worth would require careful system analysis Presumably if such noisemakers have a p lace in the scheme of things it must be to break ott contact by a tailing s u boat during peacetime A di f'f'erent family of' noisemakers could be employed by U s boats to jam Soviet f'ixed sonar installations such as bottom-mounted or buoy-mo Dlted active ar passive systems Fairly cheap battery-operated nois rs · could be planted close to such arrays It would probably cost the S U more ·' RM--23ll 10 -28-58 36 to disable the noisemakers without damage to their own systems than it would for us to place them by air drop or by ejection from the torpedo tubes Such noisemakers vith a useful life of a few weeks might be laid r in till1es of international tension as part of a low-level alert Homing torpedos both active and passive are in use These can of course be used as defensive ordnance with considerable effectiveness A submarine is not helpless against attacking ships because the submarine can usually detect and track the surt ace ship long before it is itself detected However homing torpedos can also be used against bottom-mounted active sonars The exchange ratio can be quite attractive and it should be possible to deter the s U from emplacing sizable sonars in international waters Dragging or cutting the cables to fixed installations is not very difficult especia l 1 y if' the location to drag is reasonably well known by virtue of vatchiog the installation go in Underwater demol ition team UDI' swilmners can be launched from and recovered by a submarine quite mobile instal l ations If equipped with underwater sleds such men are In shallow waters they can explore the bottom to t'ind hostile They can cut cables or disable equipment More subtly they can move equipment trom place to place or rotate 1t so it gives false bearings They can cover it with sheets of foam rubber so as to put it out of business urt r men can also mspect their own submarine to discover limpet bombs this would seem to be a necessary defensive move especially in the Mediterr ·a nean where limpets might be very attractive to the s u If Polaris submarines plan to lie tor appreciable periods in shallow waters off the Norwegian coast they might heJ p themselves by ejecting · f'rom their tubes silllple battery-operated echo- aters A bevy of such 311 lo-28-58 37 devices strewn about in shallow waters would give the s u forces a col- lection of false submarine targets to investigate and perhaps attack It should not be unduly difficult to con1truct a battery-operated device which emits a line spectrum roughly resemblillg a LOFAR signature of' a diesel engine A series of' sharp low-repetition rate pulses is needed These could be used to deceive or to saturate long-range low-trequency passive sonar - · Friendly surface shipping can be sailed around 1n the vicinity of lowfrequency passive arrays These ships can be made to put out sizable amounts of' noise a freighter running light 'With a bent propeller shaft is especially good at this and so to render the passive array nearly useless Ot course anchoring the freighter doing a f'air amount of hull riveting and then dragging the anchor across the array can be help ful additions to such a scenario Surface shipping even hostile vessels cmbe used to penetrate a barrier A submarine can run under a surface ship or hang on in bis wake Yith only moderate dif'f'icul ty 8 11d it is very difficult for search forces to find him there Unless S U destroyers are equipped vith exceptionally good sonar a daring submariner cou ld even tag along under a destroyer returni Dg to port At night during peacetime a submarine can run on the surface close to merchant shipping with very alight risk of' detection In that position radar is not likely to find hilll At night a submarine can run close to a shore on· the surface with smal l risk of detection especially if he exercises modest caution to detect unfriendly radar and sonar early enough to dive and lie on the bottom In nearly all conditions a submarine is safest at shallow submergence and he is much safer ill shallow coastal waters among islands This tactic with quietiog with an echo-reducing coa tiog an Yith a fev countermeasure ll rtiffilF RM-2 311 10-28-58 38 devices should make a nuclear submarine nearly undetectable Further discussion of sonar capabilities sonar propagation paths and ASW is given in Appendix C Missile Detection and Counter-Submarine Attack If as seems likely Pol a ris submarines Will be extremely difficult to locate in peacetime by standard anti-submarine techniques there remains the possibllity that the Russians might attempt to locate submarines by ob- serving the launch and flight of tmir missiles using patrol aircraf't The capability of this detection method will depend critica lly upon the speed with which the missile l oa d can be fired and the Navy hopes that quite short firing periods will be possible Currently 1-min intervals between firings are expected or 15 min in total and possibl y this time can be reduced However especially in the early years at operation system dif'- ficulties and malfunctions may seriously slow down this rate of fire And the longer the time needed tor launch the more opportunity is ottered the defense to locate and counterattack before the launch of the entire missile load During povered flight the missiles will probably be easy to detect by infrared tecbniq_ues from aircraft above clouds at distances out to hundreds of miles By using combinations o infrared detection and azimuth determination and radar ranging on the missile the location of the submarine could probably be determiDed within 2 n mi or less with high probability on the basis of observing one missile firing Observation of suc- ceeding missiles would yield still more precise location information Sinc e the submarine must be very nearly dead 1n the water while launching its position wilJ chal lge little between firings At 5 knots the position would • lit··· 1ij§' J - ·t m 10 1- Vf•' J iff1t· t r - ' •' f ' ' ' RM-23ll lo-28-58 39 change o 4 n mi in 5 min One possible anti-eubmarine weapon to use together with a detection system ot the type just discussed might be a 3000- to Jooo-lb ASM Yith a 1-MT warhead Each patrol aircratt could carry at least two The time ot flight to impact at a range ot 100 mi would be about 3-5 Jilin Yith a delivery accuracy ot about a mile At 100 n mi radar ranging could have a accuracy ot o 60 leas than 1000 rt and 1 n mi in azimuth is which is easy to obtain The equipaent aboard the patrol ircra tt vould not be simple but such e-1 uip ment baa been designed It would incl ude a doppler-inertia l navigation system The area coverage by such a system would be and a tire control eanputer critically lim 1ted by ASM performance and the Polaris tiring rate A system designed around a l 00-a mi ASM could expect to get an ASM on target within 5 min ot detection and voul d require 50 patrol aircra tt on station per Dlillion square miles Uthe operating a reaa tor Pol aria were limited the force requi red by the Russians to operate aD large airborne patrol ot this type vould not be It would not have to be a continuous airborne patrol like our over- water DEW operation put might a possible signal ot attack operate otten enough not to be mistaken as Jlovever the back-up ratio would have to be sufficient to operate efiectively tor at least weeks An area 1000 by 300 miles in extent in the Norwegian Sea one ot the more attractive areas tor our submarines to operate could be quite veil covered by l 5 patrol aircra tt on station However 1t the operating area vere as l arge as 5 million square ailea which would be the case w1th submarines and tenders The Norwegian Sea which is important for our submarines is one ot the most accessible areas to the Soviet Also ot great importance is the Aegean Sea and the Eastern Mediterranean Soviet patrol capabilities tbere are l 1Jll1ted now by the need 1 0 ovel'-1' ly a U 'ro country but bases in Albania c J d be built up and -poii1ib also in _tbe United Arab Republic i ' st·c RE Jf ' I I - • · I • RM- 311 l0- 8-58 4o in both the Atl antic and the Pacii ic 250 aircraft would be required on station and with a backup ot l 000 aircraft or at least 3 to l this would require a torce Such a syatem would be expensive If the Soviets chose to patrol certain areas there are alternatives open to cOU11ter the threat One is tor the submarines to launch close in to shore especially a steeply shelving shore e g inside a Norwegi Zl fiord or near a precipitous Aegean isl and This tactic could make mu ch more ditticult the attacker's precise location especially by- radar while Soviet coun ter-eubmarine warheads tailing on land would not damage a submerged submarine Sub Depth Bcab Depth rt r·- 50 f J ' 100 500 tt Damage Radius n mi Equivalent llardness in Air 1 6 2 9 10 4 2 5 3 2 4 3 6 3 8 3 3 psi 5 Other possibilities open to the Soviet Union tor ccnmtering the Polaris system are discussed in Appendix c However severai points are tairly clear l There are actions that the soviet union can take in countering t he Polaris tbreat by attempting to kill submarines and a serious effort - - 1 o b 3 1 RM-23ll l 0-28-58 41 on the enemy's part to do this should be expected tt the threat of' possi- ble Soviet actions ii ignored the capability of the torce could be reduced EspeciaJ ly in the ear4 •6o•s when the f'orce is small aud operating a reas a re lillited due to missile range the enacy- Y1ll have an opport'Ullity to detect and attack the force i l he devel opa the capability ahead ot time 2 There are however a wide range ot alternatives which appear at this writing to hold prcaise of malting extreme clitticuJ t the Job of' ccrcmtering the Fol aria force Therefore i l sensible tactics are used and i l the boats are quiet the Polaris system voald 110t be expected to suffer ma ch attrition before the launch ot its missiles B TAR mr DAMAGE CRI'fERIA The question ot vbat sort ot damage capability can be considered a deterrent 1s unresol ved Intuitively' it has always seemed that the expecta-- tion or even the mere possibility ot massive retaliation lllUSt deter a potenti l aggresaor over a larger range of circumstances tban would that ot some lesser retaliation However there ot the relation between damage capability has been no definitive a na l 7sis and deterrence and in its absence there is a tendency to gravitate toward some minimal damage capability since this reaulta in lover ayatem coats Estimates or Just pare gueaaea tor the e capability necesaar to deter vary upward fl'CD 25 per cent structural collapse ot about one l l undred cities and about ten million dead Although this lover level ot destruction would be calam1toua and the threat of it vould inhibit the Russian decia lomneke S in san e degree calamities ot greater magnitude have l ready' been survived by the Russialla Ten million tatalities would deprive the S U ot no more than 5 per cent ·r_ U -2311 l0-28-58 42 of its total population or l2 per cent ot its urban inhabitants During WW II tbe German forces at the time of their f'a rthest advance occupied territory which today contains 30 ot Russia's 76 largest cities and nearly- 40 per cent of its total population Further the Soviet popuJ ation loss resulting trom WW II amounted to something like 20 million - lO per cent ot its 1956 population Evidently even such losses are not disastrous in aey- fiDal sense for the Russians were ab1e to continue a m Jor military action vin the war and subsequently recover It be conJectured that a retaliatory force which falls substantially short of being able to threaten damage as great as tbat from which a recovery has al re been made might on some tuture occasion also fall short of' being an adequate deterrent At least there is a reasonable doubt that the threat ot lower levels of damage is sufficient The importance ot this consideration lies in the increased number ot veapona which m ust be delivered it' the desired level o f' damage is raised The achievement ot 50 per cent tatalities among the inhabitants of large Soviet cities requires about twice as nia ny Polaris-type weapons as vould be required it 25 per cent fatalities would su f'f'ice A e r doubling place i t the damage criterion is raised to 75 per cent i-----------·--·---· _________ -- -4-· -- - - ·- ---7 take s p_ _ _ _ __ _ _ _ - 4 - · - -· 1 _ - t I € b 3 _________j ---------- The above discussion does not consider evacuation fallout or tire storms all of which may be signif'icant Possible Etfect of a Civil Defense Program on weapon Requirements But even now the tull measure of the job that PolariaJ or some other SE IIEltit BM-2311 l0-28-58 43 delivery ayetem may tace bas not been considered ' 'here have been many reports ot Soviet progress in implementing a civil defense plan While those reports are tor the most pa rt vague and while there may be doubt that the measures being ta lten are ot much consequence present information is none the less consistent with the notion that population shelters resistant to perhaps as much as 50 psi may be generally available in the 19€ •a Such hardening or urban evacuation or some combination ot the two could vastly increase the ditticulty ot achie ing L cho•tm ---- _ ___ _ - d v ob jective _____ It is ot course not obvious that ve should be interested 1n maintaining our ability to damage population at same preconceived level in the face ot measures such as those mentioned It Soviet leaders elected to protect nothing but urban populations ve might properly be content with the ability to achieve some suitable level ot damage to the pby'aical re- sources represented by their large cities But 1t is reasonable to expect that Soviet efforts at civil detense will not neglect non-human resources and that the difficulty ot destroying them will be can parable to that ot kill ing people In tact our interest in tatalities arises not out ot any- conviction that f'at litiea ought to be a prime objective but tran other • RM-2Jll l0--28-58 44 sources -among them the belief' that a weapon ayatem 1 s calculated pertormance against population Vill usually be a fair indicator of its suitability for the disruption mission however defined The Disruption Force and Other National Purposes The tundamental concern or this discussion has so ta r been With the deterrence of extreme actions notably with attacks directly against the United States Hovever there is also interest in deterring other undesir- able actions and in general with 1 ntluencing the behavior of' other nations It is particularly in this latter connection that certain asymmetries between the potenti l combatants are interesting To illustrate suppose that a modest force of loV-i yload vehicles were procured With the obJect of' achieving a capability to disrupt the Soviet economy- by dusting ott several-score cities suppose too that the s u simultaneously procured a much larger force of' vell rotected high-payload missiles ao that they achieved the capability of' obliterating the American econ It may be conjectured that 1n this situation American bargaining power vould be disastrously impaired it be ratioDAl to resort to war with the on not to initiate var But the s u s u - Under no provocation would the u s vould be counted would f'eel less conetrained presum- ably signi ticantly so and would theref'ore enJoy all the better of' WlY' bargaining Evidentl y our damage criteria should not be established With- out regard tor how well it matches that of the s u This The kind of' f'orce that is not necessarily so It tor example tbe Soviet Union were to harden the industrial sectors ot i ta cities and evacuate 1ts urban populations prior to attack an opt1mal attack might be one which aimed at industrial sectors only In auch a case damage calculations made 1n tenu ot population would be misleading t o the point of' bsurdity n·· - r -- -- · i§i' CR· T -· RM-2311 l B-58 ---- - 5 is procured should not be chosen without regard tor its effect on our bar- gaining position Neither should a strategic force be procured without regard tor the possibility that same o f its elements vil l be used'otherwise than aa originally intended in the event that deterrence tails A single strategic vehicle is not customarily relied on to serve us in any time period and it is quite possible that by the time the weapons need to be used our opinions will have changed as to vhich weapon system ought to be used asainat each ot the ditf'erent sets of ta rgeta 1'or this and other reasons Polaris like all comparable veapon systems should be evaluated not merely With respect to deterrence targets but al so Yith respect to its possible alter- native employments tor counterforce targets retardation targets pin- down and in conjunction With other kinda ot delivery systems In sum Polaris is an attractive system because it seems to pranise a a uset'ul damage capability against soft known military targets and deterrence targets and combines this cape bilit r vith a baaing principle vhich oftera unique advantages Those are the first-order c011Biderations Compared with itlJ prospective contemporaries a Polaris Ddaaile may prove somevbat deficient over target Then the more dif' ficult Jobs would require several times as m any Polaris vehicles aa Atlases or other re tively high-payload vehicles But thia disadvantage seems to be ccmpensated for in no small degree b y leaser base vulnerability non ollateral damage and a mixed strategic force The advantages of submarine basing may be large enough so that too much concern should not be taken With deficiencies in second-order considerations such aa precise target coverages Ctarves for weapon ettect1veness are included in Appendix c - - BM-2311 8-58 46 C NOB-COLLATERAL DAMAGE Until quite recently strategic forces have been located on bases in the u s Without tak1ng into account either how the vulnerability ot these bases to enemy attack might be f'tected by their location or the extent of civilian cuualties tbat might result fl Olll an attack on these bases Almost all SAC baaes are at long xisting airf'ields which were built up during a period when they were expected to be used only tor training purposes The righting would be done overseas 11ow however these bases would be the prillcip l targets of a Soviet attack And it the SAC bases were attacked heavU - the damage to our civilian population especially trom tall out could be severe Moreover since many ot the air defenses protecting our cities wuld have to be penetrated in order for Soviet bombers to reach our bases the extra cost ot delivering a bQlllb on a city near a SAC base or en route would be small It it were the case that U S cities wuld 1n any event be the direct object ot attack then there would be less concern over the collocation of SAC and cities However there are 111 111' situations in which the Russians would very like1y avofd attack on u s cities Thi• wuld be the case i t they desired to destroy U S military power but preserve the u s economy for exploitation or it their veapou were lim ited to what they thought were necessary to destroy our strategic forces The Polaris system otters the possibility ot aeparating by a ver great dis ta nee our retaliatory power from our cities 'V Jltage ot the system However separation could be Thia is a real adobtained within the l illLits ot the U S if our strategic forces were l ocated in the Great Plains region a nd this central location is in tact planned tor our ICll torce - SURrrr r-r -' - BM-2311 J 0 58 47 An attack against these bases would result in veey small civilian casualties in heavily populated areas ot the countey D COMPARISON OF SEA- BED AHD LAlrn-BASED IRBM'S This section considers some ot the relative merits ot sea -based as against land based missiles ot cOlllparable characteristics 1n overseas locations More specitic l ly it attempts to xem1n the ettects ot land - baaing and sea-basing upon the ettic1eney and reliability ot the weapon system and some ot the possible political consequences ot these lterna - tive basing arrangements The United States acquired the majority ot its overseas base rights under some rather special circumstances progress the manned bomber ns Soviet Union had not ret The Korean War was still in weapon ot strategic vartare and the been credited with a signi f'icant nuclear capabilit7 These circumstances resulted in a period ot several years during which the United States could exercise and plan on the wartime use ot its overseas base system without signif'ie Dt restrictions by the boat countries however conditions have changed Nov It the Anglo-America n and French-American iegotiations Yith resi ect to the IRBM mean anything tor the future they suggest that current and tuture basing agreements especially tain to missiles will involve a much greater degree they per- ot direct control exercised by the host country over the weapon system than bas been our experience vith the manned bcaber It is true ot course that the United States is required to consult With and obtain the concurrence ot host country govenments prior to the use of overseas bases tor a wartime mission But this procedure is not nearly so exacting tor the manned bomber aa it is for a missile which baa host countr persoimel actU lly manning its launch contrci SECRET' i RM-23ll l0-28-58 48 ______ conaoles In the latter case pol itic l conauJ tation and agreement vil l not only have to occur prior to missile launching actual missile launching vithout such agreement may prove impossible except conceivably tor the host country What these possibilities suggest is that overseas land-based missiles are likel1 to have built into them signiticant political dela y times in addition to their normal countdown times Beyond that it is easy to con- ceive of circumstances in which their use might be denied to the United States or l ess easily contingencies in which the host countey might tire the weapons without American concurrence In short overseas land-basing of missiles might appear to a reaction time ot the missile and thereby increase Lengthen the its vulnerability b Introduce a considerabl e el ement of uncertainty as to the availability ot the missile to the United States c Make possibl e the launching of the missile without the consent ot the United States Sea-based missiles by contrast vould not appear to sutf'er f'rom these I liabilities to the same extent The system coul d be kept under full American control decision times presumably would be aborter and the United States could determine the circmnstances of the weapon's use Even should the United States desire to ha ve supporting tenders at such places as Scapa Flow Rota or Suda Bay vailabl e tor these systems 1ts bargaining posi- tion with respect to their command and control ahoul d be better than in the caae ot land-baaed missiles since the option to move to otber locations vould aJ waya be available in the event or either unacceptable conditions· or changed attitudes on the part of host country Or perhaps of lesser importance sea basing of the missile would also provide greater ilrmu nity from sabotage and perhaps somewhat increased varhel d security Overseas land-based missiles run the risk ot engendering certain adverse political etfects to a greater degree than is likely to be the cue with sea -- based systems Land-based systems i f widely dispersed will need real estate beyond current manned aircraft requirements It not actually accident-prone they ma y nevertheless create a tear of accidents especiall y i f they should be mobile ' bey will involve the presence of aome American personnel and thus continue the problem ot troop-community relations Because of their presence these missiles may well increase the fear ot the host country tb t it will become the target ot a thermonuclear attack And because they can be seen they Vill serve as constant reminders both of the balance ot terror and of the host country's role in it Precisel y how these imme- diate effects would manifest themsel ves 1n the internal and external political behavior of the host country is most uncertain But it is difficult to believe tbat they would not result in added hostil it y to the United States and its policies with the further effect of increasingly strillgent conditions concerning the use of the weapons Se -based missiles do not raise real estate problems Accidents that occur to them are likely to happen at sea since the submarines will be away from their tenders 80 per cent ot the time They do not add signiticantly- to the problem of troop-community relationships As targets of enemy attack they do not represent the same hazard to populated areas that land-based missiles do And because for the most part they will be out of sight so they may be out of mind Far less stigma tear and political agitation ·J SEC REl RM-2311 l 0- 28-58 50 are likely to be associated with sea-based missiles by friendly or uncommitted nations as compared with land-based missiles of a similar type Although the sea-based missile may seem prefex ble to the overseas land-based missile in tel'm8 of the politic l constraints and sensitivities that are generaJ ly operative abroad tvo cautionary points may be worth mak1ng- P irst there may be overseas areas outside the European theater on which missiles may be based in either a bard or mobile configuration without suffering from the politic l detects that have been discussed above Of f'hand the prospect does not appear too pranising i'ran the standpoint of ensuring both American control and political reliability over extended periods of time but investigation of the attitudes and receptivity ot particular countries might indicate otherwise Secondly to suggest however tentativel y that sea-based missiles may be preferable to overseas land-based missiles according to the political criteria used here is definitely not to recommend the surrender by the United States ot its overseas base rights These bases premise to figure very importantl y in AJDerican lllilitary and pol itical strategy tor a l ong time to ccme -'lot -· SEGRE-l u l - 8-58 5l Appendix A GUIDANCE In the vel ocity-to-be-gained guidance scheme for Pol aris an airborne digital computer solves a set of guidance equations based on an inertial coordinate system where x y are in the vertical thrust plane at 45 deg to the local gravity vector and z 1s norma l to the x-y plane The integrals or the thrust and lit't accelerations are digital input6 into the digiteJ comruter from the integrating accelerometers in the inertial measurement unit The 1nit1e l velocity conditions are set in by the sub-based tire control system Thrust is cut off when V whose direction is approximately long the thrust vector attains essentially a zero ve l ue For steering VS and Vgz are driven to zero by proper control of the m1ssile 1 s thrust vector There are eight preselected targets tor the 16 missiles on boa rd the sub For these eight target points and tor launch points 1n the centers or 20 x 20 n mi grids precomputed inputs to the guide nee equations a nd the azimuth direction of the x-- plane are stored on cards The tire control computer interpolates these values to obtain the proper settings for the exact launch point In tbia ceJ culation the velocity ot the sub is taken into account in determining the initial velocity inputs information is obtained from the SINS system The b sic velocity It is presently planned to launch missiles with essentially no submarine velocity INERTIAL MEASUREMENT UNIT The major elements of tbe Polaris inertial iaeasurement unit are a J RM-23ll lo-28-58 52 conventional outside-in gimbal system three single egree-of-freedom floated pendulous integrating gyros for integrating acceler meters resolvers and associated electronics There will be no sbockm ounting of the unit The order of gimballing from inside out is yaw roll and pitch with angular freedoms of± 36o ± 30 and 30 to - 90 deg respectively Resolvers are required between the inner and middle and between the middle and outer gimbals for both platform stabilization and missile control system angular reference The input axes of the three accelerometers are oriented along the x y z coordinate axes The gyros are oriented so that the input axis of the pitch gyros is a long the z axis The input axes of the roll and yaw s ros are in the x-y plane but not along the x and y axes Instead the yaw axis is along the local gravity vector and the roll axis is normal to it This orientation does not minimize the effects of dri rt due to mass unbalance in the yaw gyro However dri rt is not a dominating t'actor in nmM accuracy A constant one-degree-per-hour dri rt rate results in a one ile miss at 1500 miles ERECTION AND ALIGNMEN'l' The platform is erected to the local gravity by nulling tbe sum of the outputs of the x and y accelerometers plus a correction for the velocity of the submarine obtained from the fire control computer It' the sea le factors of the x and y accelerometers were the same this would simplify the operation One ot the specit'ications on the accelerometers is that their sea le factor be within 0 01 per cent of standard Since at present it is not known how the sea le factor of pendulous integrating gyros fluctuates with time this specification seems difficult to meet Furthermore since the accelerometers are being used for erection their scale factor cannot be SF ET' f - RM-23ll lo-c 8-58 53 easily checked and corrections put into the airborne computer to compensate tor any such ahitts The azimuth reference for alignment is to be supplied by the SINS system made up ot three separate SINS units flexing ot the submarine structure It is assumed that there ia negligible Since the mirror on the platform is attached to the outer gimba l and not to the yav gimb l back- ack reaolvers re uaed to drive the platform to the proper azimuth orientation trical a nd mechanical null alignment or The elec- these resolvers must be kept within 20 aec of arc PLATFORM 5 l'ABILIZATION The stabilization loops b ve a ba nd pass ot approximately 20 cycles per sec The maximum torque output o-r the torque motors tor the pitch roll and yaw gimbals respectively are 1 2 fi-lb 2 4 rt-lb and 2 4 tt-lb These -q lues are quite low and require that the uncertainty torques and the maas unbalance ot the gimbals be kept quite small Otherwise a large por- tion o-r the avail able torque will be uaed up and very little torque would be left to isolate the platform from missile motion Since no production platforms have been assembled no teat have been m d e to determine the uncertainty torque• and the effect• ot maas unbalance under high g 1 s fuge tests or a Centri- complete platform must be made in order to determine these effects GYROS Am ACCELEROMETERS The gyros are single-degree-of-treed om floated integrating gyros made of beryllium 25 IRIG They have been designed by MIT and designated by them as the The integrating accelerometers a re floated pendulous integratin · -- ' •• - f'#ii-' I ' • 1 - SECRET gyros based on the 25 IRIG and designated by MIT a s the 25 PIG a digital output wheel by They have Both the gyros and accelerometers are being built the tour previously mentioned companies directlY trom MIT drawings So tar there are no test data available from production units to indicate their To insure a quick reaction time it is planned to supply the performance proper amplitude ot 6o- ycle power to the gyros and accelerometers so that the spin motors will operate at a low speed and yet produce the same temperature distribution as when the rotors are opera ting at airborne speed This concept has not been fully tested to indicate that there will not be a temperature transient when the spin motors are switched to airborne frequency THRUST VECTOR COlffllOL The thrust vector is to be controlled by positioning Jetevators in the rocket exhaust The successful developnent of these jetevators is a major problem area primarily because of high stiction levels encountered due to Jetevators have been used in the past the elevated temperature condition but not tor the relatively long burning times of the Polaris motors which are ot the order of 69 sec per stage The angular information tor the control system is obtained trom the resolved gimbal angles of the inertial measurement unit The angular rate i ormation is obtained trcm body-mounted rate gyros PITCH CHANNEL Instead or using a pitch angle program to attempt to obtain a zero 11 rt trajectory during the first stage the appropriate trajectory is programmed by the use of an equation employing velocity inf'ormation during the tirst stage or a pitch rate command signal The values of the constants in the 'i I I • · - RM-23ll 10--28-58 55 equation determine the shape of this part of the trajectory which is the same tor a 11 ranges computer The pitch rate command is an output ot the digital This method ot producing the approximate zero-lift trajectory is superior on tvo accounts to programming the pitch rate directly It reduces the angle attack of the missile in the presence ot vind shears and nonstandard thrust conditions and it materially reduces the velocity error at staging due to non• tandard thrust conditions and wind Atter staging the pitch steering is changed to the cross product steering using the velocity-to-be-gained information This method of steering is excellent since time variable gains a re obtained automatically which properly tighten up the velocity control loop as cutoff is approached This method of control is similar to the one used on the Thor YAW CHAmm Since there is no programming to be done 1n the yav channel gross product steering is used in both the f'irst and second stages ROLL CHANNEL Roll control is obtained by merely nulling the appropriate _resolved gimbal angle STAGING It appears that stability at staging may be a serious problem At staging the second stage is aerodynamically unstable until thrust comes up there is no way o controlling the second stage Fins or a skirt couJ d increase tbe stability but this would add extra weight and drag Another problem is the possible colliso of the first stage with the second stage during t he time the first stage thrust is decayi and the second-etage - I - l' · 1 1 -· • SECRET p -· RK-2311 lo-28-58 56 thrust is coming up POSSIBLE PROBLEM AREAS l Reliability and maintainability of the very complex fire control system 2 Ability to get information for correcting the SINS system so that correct azimuth and position information is available tor inputs to airborne guidance system Jetevator develoinent 4 Solution to the second-stage stability problem and to the problem of possible collison of the first and second stages at staging vithout the addition of too much weight and drag to the missile 5 Possibly too low maximum torque available for torquing the gimbals This is dependent upon the uncertainty torque l evel s and mass unbalance of the gimbals in the production pl atforma 6 DifticUlty of launching in rough seas 7 Scale factor shitts in the accelerometers 8 Problems in production of the guidance system SE·CREl RM-23ll 10-28-58 57 Appendix B COSTS COST ANALYSIS Installations Base Facilities One Missile Assembly- Facility MAF tor the initial force of nine submarines and one tender is contemplated This MAF is planned to be built at the Navy Ammwiition Depot at Charleston South Carolina by October 1960 and is to have the following capability Assembly rate • • 8 missiles per veek Outloading rate • • 16 missiles per week Storage capacity • 90 missiles Construction costs are estimated at $10 million vi th an additional $7 million for equi1111ent Training Facilities A crev team training facility vill be erected at Nev London Connecticut to provide crew team tra1n1ng for the double crew per submarine program The breakdown costs are as f'ollovs Building • • • • • Equi pnent and Air Conditioning •• FBM Team Trainer $200 000 153 000 •1 6oo ooo $1 953 000 See Table l page 23 ·'Ii RM-23ll 10-28-58 58 These are shown in Table las $0 4 million for training facilities and $1 6 million under training equipment There is a possibility that another similar crew team training facility might be constructed at Charleston depending upon the availability of funds and the magnitu de of the program However the training capacity at New London represented by these costs and those under training equipment are sufficient to train two crews through the first eleven submarines or a total of twenty-two crews Base Maintenance The $3 4 million is a Navy •figure and it is not known precisely what is included Using Cost Ans l ysis Department methods the maintenance of the incremental facilities should be around half a million dollars per year Equipment Submarines The Navy gives the cost of nine submarines as $900 million This corresponds with a previous estimate of $109 million for the first submarine and $100 mil lion f'or each subsequent submarine It is felt that over time these costs per submarine might be significantly decreased The funding summary as presented in FBM Program-Polaris lists expenses by categories for the thirteen submarines which they consider The average estimated cost for one submarine obtained by adding together each fiscal year's funds allotted £or each category and dividing by thirteen is Item Millions of Dollars Ship Construction Launch and Handl iog Fire Control • • • • • • • Navigation • • • • • • • • Missile Checkout • Test Instrumentation Weapon System Trailer • 2 49 31 44 $ldi · 39 Lt· · · Total • ru $ 78 72 6 36 7 6 8 46 u ECnltltt l 3ll 1 8-58 59 Under the category of ship construction are included the folloWing nuclear powerplant Bureau of Ships Eq pment procurement basic construetion equipment installation conventional submarine ordnance and electronics - ·7 I equipment fi ' r' G J 7- 11 --- - --- ---- --- - ------ --- ---- -- -- --- -- -- --- --h- _ ' Estimates of expected maintenance and replacement of launch and hand ling fire control navigation missile checkout test instrumentation and weapon system trainer components aboard the submarine were not available Assuming a canplexity of equipnent comparable to that of equipnent used in the missile subsystems for which replacement at the rate ot 20 per cent per year is current Navy thinking an annual charge of $ 8 million per submarine or $43 2 million for the system vas made Tender The tender cost ot $26 million applies to the modi f'ication of an existing ship Construction of a new tender at a cost of $61 million is planned if the system grows and if t'l lllds are available The tender is a t'loating maintenance and repair facility for both the submarines and missiles and is equipped with vary-ing classes of machinery and electronic gear The dollar cost of these items is hidden in the initial investment expenditures for the tender To be ree listic this equipment should be charged ordinary depreciation maintenance and replacement costs Since the tender does service missiles it is reasonable to expect that the equipment on board rll1 contain missile checkout and test instrumentation gear The cost of these items on board the submarine averages out to $2 8 million and it is assumed that the tender will be similarly equipped lf this is considered to be equivalent to base equipment annual charges of 18 per cent are usually applied However to be consistent ' he 20 per cent factor used iUP 1 k4L r · •1JN w lg1r t 1 RM 3ll 1 8-58 6o for submarine equipment w s used It is believed that the tender will al so house refresher training equipment but these costs have been included under the training equipment category The Navy source used to obtain annual operating charges lists about $200 000 per year for supplies and equipage In Navy terminology supplies are consumable items and include electronic and machinery repair parts soap swabs etc Equipage incl udes more durable items such as special clothing life Jackets typewriters etc It also includes sheet metal and repair items used by tenders to repair other vessels This cost has been included under Services and Miscellaneous in order to avoid double counting Missiles cluding spa res The cost obtained for the missiles vas $1 339 750 each inThe spares philosophy used was suf'ticient to replace the complete missile every five years or 20 per cent Deducting this amount the price of the missile al one becomes $1 07 million It is believed that the cost of the missile represents production missiles and excludes those produced for development and testing the varhead is al so excluded A breakdown of missile component costs obtained frcm the Special Pro- jects Office at a lat r date gives a maximum and minimum for the various components The maximum represents current experience the minimum represents what they think they can do with direct contracting and a better learning curve None of these costs includes any al lmra n ce for spares for checking equipment or for containers The same cost was used for both limites of Guidance 11 which is an certain item SEC'RET 7't W'l- RM-2311 1 8-58 61 Cost thousands of dollars Maxi mum Minimwn Subsystem Propulsion 6o per cent of cost in first stage 4o per cent in second $250 Re-Entry Body less warhead •• •• •••• • 32 20 5 Flight Con trol 43 16 In ters a ges i e power supplies wiring separation devices etc • • • • •• 177 8o Guidance 50 50 $552 $200 $366 5 Since the missile cost could not be resolved in the time available the highest cost of $1 07 million was used in t he interests of conservat ism The number of missiles for the system for which cos s were given was 144 including spares the tender load However this does not include an amoun c suf't'icien t for Consequently costs of an additional 16 missiles plus spares have been in luded in the estimate No additional information on t he training firings of missile above that of one firing per year bas been learned Official Navy policy appears -co be very conservative concerning the use of expensive ordnance for training In view of this existing policy three firings per submarine per year were assumed in expect a t i on t hat the policy will change as the system matures and is made comparable to other systems However this cost category could read $1 07 million per year if the existing training philosophy was rigidly adhered to Missile Containers In order to keep the missile under suffi cient environmental cont rol to preven any damage t o t he propellant grain duri g t ransport containers are provid ed Environmen t emperature has been 1111t ' natt RiETr· RM-23ll l 0-28-58 62 specified at 8o0f 3°F These containers are listed a t $8 110 000 This amount is held sufficien to purchase enough containers for 144 missiles Unfortl lllately the specific number of containers represent ed by t his figure was no available A one-to-one ratio of missiles to containers is discounted as the use of these entails recycling Applying the spares figure of 20 per cent to the containers as annual replacement we obtain $1 6 million which was used to represent annual operating costs Base Equipment The seven million dollars represented here is for the equipment in the Missile Assembly Facilit y building Annual operating charges of 18 per cent have been applied agains t this figure folloving CAD procedure in lieu of any figure furnished by the Navy Training Equipment This category includes the following i 1 ems accord- ing to data obtained Item Cost thousands of Dollars Attack Teacher •• Diving Trainer •• $2000 700 Refresher Training Equipment •• 500 Maintenance Training Aids •• 575 Operational Training Equipment 550 FBM Teem Trainer • • 16oo Total $5925 The FBM Team Trainer wi11 be installed in the crew team training facility There is some speculation as to whet her three Attack Teachers will be bought At this time the purchase of one is certain It is not known whether the other wo are held in abeyance due t o lack of funds or due to uncertainty as to how many are needed to u lfill its mission -1 l I · •1 _JtJ SECRET' 70 The Special Projects J't t 1 • • SECRET l RM 3ll 10-28-58 63 ottice claims that the training acilities and equipaent delineated above are adequate to train two crews per submarine through the irat eleven boats Annual operating costs were obtained by applying the 18 per cent tactor s in the case ot base equipnent Training equipaent for the Polaris system ot 144 missiles trail the costs available is about ¢6 million which is considerably less than the costs under training tor Air Force ballistic missile systems such as Atlas or Thor ing a Conaidering the factor-of-five difference in personnel and assum- factor-of-two tor complexity tbese costs are partially resolved aowever caution is warranted tor this category pending turtber in tormation stock a Init1al Spares and Readiness Reserve Using a stock level toll awing tactors used by the Navy tor logistic support ot Naval vessels and cost t1gurea tor nuclear sul marines 9 4 mill ion was the initial investment estimate Initial Spa res-Missiles The tigure ot ¢43 2 million vas obtained u described under Missile Equipnent Initial Spares-Shipboard F M Szstem amount obtained tor this item No turtber im'ormation regarding the spa res policy tor this category was obtainable ing tbe Bine million dollars is the However this seems low consider- average coat ot shipboard components ccmputed above It ve include launch and handling tire control navigation missile checkout test instrumentation and the weapon syatem trainer tbe total average coat is j$25 J mill ion per submarine Nine million dollars is 3 9 per cent ot the total cost o ¢231 3 mill ioD for the nine boats which is a low spa res factor SECRET 77 r - 1 _H ·l • • t •·• 1 i l •i RM--23ll lo-28-58 64 · i S I D ''ti · 1r· i J 1 • Hence this figure is conjectural as it is not knovn exactly what is included Spares cost for tbe naval vessels are usually included in the vessel procurement ccsts Hence it is assumed that the initial spares for sub- marines and the tender but not for the missile subsystem are accounted for in the purchase price Transportation The major item here is the cost of shipping Polaris missiles Because of dangers involved due to cracking of the solid propellant grain and its requirement for environmental control it is assumed that the missiles will be flo-wn from the manufacturing facility in California to the Naval stations in the East A Lockheed report gives the weight breakdown and estimated costs of flying these missiles using C-133 aircraft missiles comes to about $2 6 million The costs for transporting 16o To this is added the costs of trans- porting ammunition and other supplies Annual operating'expenses represent costs of flying 20 per cent spares as veil as annual supplies replacement Personnel Nuclear training vill be taken by 40 enlisted men and three officers per crew or a total of 774 men for the nine-crev complement Formal nuclear training takes six months plus six months training at the prototype One- half of each crew goes to the shipyard at which their submarine is being constructed twelve months prior to commissioning - -- SECRET Tbe other ha lf of the RM-231 l 10-28-58 65 crew reports to the shipyard nine months prior to commissioning The Navy costs figures for this training is $200 per man per week for 2236 man-weeks or of $10 400 per man course $8 o49 6oo for the 774 men This is equivalent to a total This figure includes all overhead associated with the It is notable that the cost of nuclear training for the FBM system is the same as the nuclear training for any other nuclear-powered ship FBM Technical Training for the initial system is given as $2 088 000 The breakdown shows 372 man-weeks for formal training plus 150 man-weeks for special weapons training The costs as given indicate that 522 men from the eighteen crews will This implies that of each crew 43 per cent take nuclear take the course raining and one ha lf of the remainder 28 5 per cent take this technical training Thus it appears that 28 5 per cent of the crews do not take any special training at al l It is important to realize that costs of submarine school training and special 1st training are not included in this estimate and therefore the amount show understates total training costs Replacement Training Using personnel numbers obtained previously and arbitrarily augmenting the crew proportionately to account for an additional -workload imposed by three more submarines now nine instead of six the following estimate -was arrived at Personnel for nine submarines and one tender Officers Squadron • Division • Support Submarines Tender Total Enlisted Men Total 30 9 6 6 300 15 18o 1620 30 852 330 18oo 882 255 27 3039 6 l JJ 12 RM-23ll l o-28-58 66 The turnover rate received from the Special Project s Office a s 20 per cent per year Charges were me de f or basic training a t $3200 per man Costs ror nuclear and technical training were added under the assumption that the same percentage of the replacements would take these courses as in the regular force Again these costs are underestimated by costs of submarine train- ing and other specialis't courses Pay and Allowances $10 000 per officer and For submarine personnel pay and allowances of $5000 per enlisted man were used for other person- nel $ oo per officer and $34oO per enlisted man were used Travel The estimated obligations for FY 1958 under the account movementspermanent change of station as listed in Congressional Hearings for 1958 were used excluding the travel of midshipmen aviation cadets and officer candidates Maintenance and Fuel Submarines Annual overhaul restricted availability charges and the cost of replacing the pucl ear core are incl uded in maintenance The cost for recoring is from $3 to $3 5 million every 30 months Again the higher figure was used a nd prorated on an annual basis Costs for maintenance and replacement of equipment pertinent to the Polaris are accounted for under the equipment category above The Navy defines restricted availability as including costs of labor and ms terie l s for nonscheduled repairs Nonscheduled repairs are defined as repairs occurring between regularly scheduled overhauls to accomplish specific items of work such as routine minor repairs repairs occasioned by collision grounding fire dama ge etc • · r r· ' I ii 1 111 • SECRET ' RM-2311 10-28-58 67 Tender This che rge of $300 000 includes charges for overhaul fuel and restricted availability Supplies and equipage training ammunition and medical costs have been included under Services a nd Miscellaneous to e void double counting If the items attributable to the tender as annua l costs are accumulated under one heading the total amounts to $1 2 million yearly Services and Miscellaneous Materials supplies and contractual services for administrative work medical and food services - training ammunition and miscellaneous POL fall in this group Miscellaneous POL ra s computed at $100 per man per year since it was not possible to distinguish utility services and fuel costs Command Administration In estimating weapon systems costs it is desirable to include the prorata share of the intermediate and major commands which support the opera- tional units I a ck of information prevented use of In- a similar method stead Navy Appropriation Account titles were examined to determine those most applicable to the Polaris system Items in these accounts relating to major equipment expenditure were excluded in an effort to isolate annual expenses and to prevent inclusion of inapplicable items The Polaris system's proportional share of these expenditures -was then estimated Interim Communications In the Navy document Flee Ballistic Missile Program Polaris FY 1 59-60 estimated funding requirements are given f or the program through FY 196o is w s not done in t his r eport in order t o make the various categories as comparable as possible to the usual RAIIP f'ormat 11 tEe a t rf ·_ - I RM 3ll l 0 8-58 68 Admittedly this program is for 13 submarines with growth potential through a total of 25 Command Communications Under the broad heading of Logis t ics and Oper- ational Support command communications in the amount of listed $92 414 ooo a re This is of course an optimistic program but some parts o t' this amount are necessary for the mature Polaris system even if only bare essentials are provided List ed under Camnl lllications and Facilities Equipment are a Augmentation of VU' Maine Equi pment and Facilities b overseas Radio Receiving Equipment and Facilities c Communications Field Test d HF Radio Station Funds requested for the above are $46 176 000 for facilities and $6 450 000 for equipment through FY 19ti These items provide in the Navy's own language on1y an interim commUllications capability Hence it appears reasonable to include this amount in the initial investment for the system The sum of $39 074 ooo for the developnent of new and existing VU' equipment devel opnent of HAP E t ansmit ters and receivers SESCO Whisper programs etc may be included under Research and Development The implications are however that since the $52 6 million for com- munications prov1des only int erim capability expenditures for facilities and equipment will probably be required Annual charges using factors of 5 per cent of facilities costs and ll per cent of equipment costs have been ma de This cost appears as an addition to the Table l rather than as part of the body of the table because funds for this portion are not yet authorized and conceivably may never s ee t he light of day J I _ 1•f - • 4 • iS EC'RE -· The main parts of t he table - - BM-231 l 1 8-58 69 express the costs of the items which are most certain of expectation and hopefuJ ly the implications of costs on annual operations Research and Development Available references 11st Rand D expenses for the system as a 'Whole as between one billion and l o4o billion dolls rs The precise content of this category is obscure however idee J J y it should include the various research and development programs pertaining to submarines communications nav1gation and guidance which are directly applicable to the Polaris program This obviously would include ex penditures for the Ocean Survey program for the Compass Island and Observation Island experimental test ships etc Thus in order to include costs incurred by the system this category is al so shown separately As elsewhere the highest estimate bas been used in the interests of conservatism - - RM-23ll lo-2 58 71 ppendi x C UNDERSEA DETECTION AND ASW This section considers the undersea warfare methods 'Which the Soviet Union might employ in defense against the Polaris system Throughout the field of undersea warfare which is as broad and complex as the field of air warfare underwater sound devices a re the counterparts of radars in air WS rfe re However underwater sound devices genera ll y work very poorly as compared 'With their radar counterparts This fact tends to give a n intrud- ing submarine a relatively greater advantage than say an intruding aircraft Hence the Soviet Union might use other undersea warfare devices such as mines or underwater swimmers to supplement the more conventional A SW forces GENERAL STATE OF THE SONAR ART There is a despread impression that the field of sonar is not rea lly well developed that with a big push real breakthroughs could be obtained that heretofore the field bas perhaps languished for want of real ta lent and real money Certainly' more money and more ta lent would be welcomed and would be useful but the basic impression is entirely erroneous Sonar is at least as highly developed a field as radar There are few techniques in the radar bag of tricks which have not been at least examined usually tried out at sea in sonar Indeed just because the sonar problems have been bard er than the radar problems at any particular time in history the sonar scientist has often been driven to try b a rder and to try fancier tricks Hence many of the newer techniques in radar are fairly old in sonar On the whole the tvo fields are about even as far as technica J development and basic understanding of the physical p esses a re concerned SECRET Rade rs RM-23ll 10-28-58 72 are far more numerous more varied and more commonplace but these differences do not indicate a corresponding difference in understanding On the whole pretty fair guesses can be ma de as to the evolutionary course which radar will take at least plans for the future are made on this basis and In sonar at least that is really the important point for this discussion among those who are not familiar with the subject there is sometimes an inclination to think that matters are different This view amounts to a denial of the present understanding of the field it i _s an unwillingness to plan for the future on the basis of what is actually known it is nearly a hope that a miracUlous cure will dispel unpleasant reality It is unwarranted Much is already lmown about sound in w ter and there is no more basis to anticipate a big breakthrough in sonar than in ra da r The ma in avenues along which sonar improvement can be expected have been clear for years and development is proceeding down them higher I adiated power better radi- ation patterns lower frequencies bigger arrays and improved signal processing As with radar more data are needed on long-range propagation especially over-the-horizon effects and long-range clutter However one can make fair estimat s of the improvements to be expected from a given effort It is the ocean not just the engineering skill wich sets the limits and the costs on performance In both radar and sonar the question is not really whether a major nation has the technical know-how to obtain a certain capability instead whether the nation chooses to pay the price It is Ju st as a sufficiently numerous assortment of radars couJ d be used to track small low-flying aircraft anywhere in the U S so too a sufficiently numerous assortment of sonars could track a submarine any -here in the ocean The cost of such radar coverage is astronomical so is the cost -such sonar coverage SECRET lo RM-23ll 10-28-58 73 SONAR PROPERTIES ·oF THE OCEAN Before considering the performance of specific sonar systems it is useful to outline some of the relevant characteristics of the ocean In a general way these establish the nground rules With which the sonar designer is faced Inasmuch as sonar almost never vorks as well as its radar counterpart it is helpful to note some of the differences which lead to the disparity The velocity of sound in sea water is approximately 48 x ft sec The velocity is dependent upon both temperature and pressure so this is only a rule of thumb Sonar is at a disadvantage with respect to radar because of this slow information rate The ratio of propagation velocities is about 200 000 whereas the ratio of typical vehicle speeds is genere lly about 100 so the disadvantage is real and is not compensated by slowing do'Wil the clock The attenuation of sound in sea water is quite severe except at very low frequencies At 24 kc vbich is a convenient frequency fran the standpoint of WB Ve Length 2 4 in the attenuation is about 5 db per kiloyard one way In radar the attenuation in the medium is generally trivial even at long ranges except for the water and oxygen absorption bands echoing range of 4o oqo yd vhich 1s mod est for radar a have to overcome 4oo-db attenuation which is fantastic To achieve an 24-kc sonar would Fortunately for the sonar designer this attenuation is quite frequency-dependent and is much more moderate at low frequencies at 10 kc it is about l db kiloya rd and at a few hundred cycles it is of the order of' 0 05 db kiloyard These lower frequeo cies involve longer wavelengths and consequently large arrays and not much work was done in low frequencies until at'ter Wgrld War II At 24 kc the standard U S frequency during World War II the wavelength of sound in sea water is as we have seen about 2 4 in sonar is in many respects canparable to 4900-mc - ij CRET Hence such One may compare the RM-23ll 1 8-58 74 dimensions of the· radar ant enna with those of the sonar transducer directly even beamwidths of only a few degrees require radiators less than 6 ft in diameter However attenuation precludes use of such sonar frequencies at ranges in excess of a very few thousand yards To avoid attenuation the designer may go down to say 10 kc Here the attenuation does not make echo-ranging impossible out to ranges of perhaps 20 000 yd but the wavelength is 5-3 4 radar as far as antenna size goes in This is comparable to 2000-mc Sonar radiators 10 or 20 ft across are quite practical but it is rather difficult to drag a 20-ft diameter object through the -water beneath a ship To get really low attenuation and hence to make possible ranges of say 100 m11es the sonar designer is driven down to frequencies of the order of l kc to 200-mc radar Here the 'We Ve length is 4 8 f t--comparable Arrays of the order of 100-ft long are needed to achieve bee mwidths of a couple of degrees and such arrays begin to approach the dimensions of ships themselves If attenuation alone limited sonar hugh low-frequency sets would long ago have been built t o the sonar man However sonar is plagued by clutter--or reverberation y the most sophisticated modern radars are significantly aware of clutter arising from any scatterers except the earth's surface but sonar is relatively much more 11 mit ed by reverberation than is radar Part- ly this i because ven the deep ocean is a rather thin layer of -water It is as if t he atmosphere were only about 12 000 ft thick with another solid earth and trees up above Under such conditions one would see radar tar- gets free of ·clutter only at very short ranges and that is exactly what happens to sonar gets For long-range sonar all targets are 11 low altitude tar- Furthermore the ocean is surprisingly inhomogeneous not only beca1 15e of marine organisms but also because of t empera e and salinity gradients RM-23ll 1 8-58 75 All these lead to reverberation from the body of the water itself and this tends o became very important in long-range systems It is as if our 12 000- ft radar atmosphere were thoroughly cluttered with birds of assorted sizes and shapes Also the ocean exhibits marked refraction effects which sometimes help and sometimes hind er ea ch party in the ASW problem On the one hand down- ward refraction tends to limit the range at which a sonar near the surface can detect a target beyond this range the sub marine is below the horizon On the other hand surface ducting can lead to greater than average range Downbending is connected with reconvergence effects and it is presently hoped to extend sonar ranges significantly e g to 30 and perhaps 6o or more miles by echo ranging in reconvergence zones Refraction cond i ions e lso Wlderlie the existence of the deep sound channel whereby SOF AR and LOFAR achieve very long detection ranges in deep water Variations in refractive paths contribute to rapid fluctuations in the phase and amplitude of signals propagated ove - appreciable distances These modulations smear the signal spectrum in much t he same manner that radar ground clutter is smeared and t his hampers sophisticated signal-processing schemes which rely upon signal int egration Othe sonar characterist ics of the ocean of less importance deserve men ion One of these is nat urally occurring noise Whereas the deep ocean basins e -e f airly quiet except f or sound which l aks down from the t op this is not a t all true of shallower wat ers such as surround a 11 the continent s n virtue J ly all shallow t ropical and tempe -ate waters noise produced by marine lif e e g crackinG shrimp croakers sroaners etc is a definite i lpedimen t to passive sonar whi ch seeks to detec quiet targe s - In addition RM-23ll l o-28-58 76 the noise of surf b e kins on a coast or in whitecaps at sea hampers listen• ing The noise of the wind itself is not ne ligible Aboard surface cre t t he noise o the -waves washin5 age inst its own hull puts a lower liz lit on the backsround sel -noise level that such a ship can achieve In arctic regions where ice occurs the noise level of the ice moving around against itself or against a shore can be high Bottom conditions affect sonar perfo 1 lB Ilce especie lly on continental shelves These ve cy 'rom exposed be re rock to deep sot't mud In the former bottom reverberat ion is severe in the latter bott0t 1 absorption is severe t here is some ki d of sonar operation which will be affected adversely for whichever extreme occurs This tends to f'orce the sonar designer to design his system i e frequency pulse l ength radiation pattern etc to fit the particular area in which it will be used However these bottom con- ditions vary rather quickly f rom place to place and the 11 optimum sonar may be one which does not work very well in any one place in order to comprise among the highly diverse conditions it must meet The attenuation of sound in sea wter is so great and so frequencydependent that for practical purposes one can be confident that any sonar I system which operates over acoustic path lengths of only a couple of dozen miles must use audible frequencies Hence for such systems the entire opere ble frequency range above about 50 cps can be monitored by one pair of human ears This s'ituation is in drastic contrast to the radio and radar frequency ranges which are so wide that elaborate search receivers are needed In the microwave region especially quite secure communication could be achieved by hiding a narrow band signal some place in the many available kilomegacycles This 1s Vir'tually impossible in sonar with a simple hydrophone and amplifier one man can cove e whole oand RM-23ll 10-28-58 77 simultaneously and continuously sophisticated signal processor Furthermore the human ear is a fairly When a man turns his attention on a particu- lar signal in a background of interfering signals he is using a tunable filter of ad Justable bandVidth which he can narrow down subconsciously to less than 50 cps Consequently secure sonar camnunication systems are to be ta ken with a grain of salt the opera tor might not recognize the signal but he would probably' detect it For the same reason it is a simple matter for a submarine to monitor for hostile sonar except at short ranges he cannot be significantly threatened by a signal he cannot hear To cover even tbe frequencies which could be used against him at very short ranges the submariner need use only a few more ears with fixed-tuned superhet receivers Just as radar surfers a peak power limitation because of dielectric breakdown so sonar is peak-power-limited by cavitation of the ocean For typical shipboard active systems cavitation sets an upper limit on the pulse power which can be radiated This precludes the possibility of raising t he power sufficiently to overcome own-ship noise at high speed and so shipboard sonar is speed-limited Cavitation also precludes raising the out put power by dozens ot db in order to work into the refractive shadow zone by scattering The very large high-power systems which are now under development or presently proposed are all quite low-frequency systems To get useful directivity patterns they require radiators so large that even at a mega'W'B tt power level the intensity at the radiating surface would be canparable to existing sonars At megawatt levels the prime sources of power pose greater problems tban does cavitat ion - ilRGRET tl 91 RM-23ll 1 8-58 78 Because of the requirement to use low frequencies in order to achieve long ranges sonar pulses must be very long in comparison With radar puJ ses At the very low frequencies sonar designers are finding it desirable to use pulses of the order of 1 second long and even longer Consequently 1-megawa tt pul se power in sonar is much more of an engineering problem than is 1 megawtt in a radar whose pulses are a microsecond or so long Such sonar pulses a re so long tba t the pulse length compares to the thermal time constants of the system and the engineering problems begin to take on sane of the aspects of l megawatt cw People are thinking in terms of self-contained nuclear reactor supplies to provide the radiated power in some contemplated systems SONAR PROPAGATION PATHS Until very recently radars operated over a simple radar-line-of-sight transmission path refraction conditions occasional ly produce ducts and holidays but these are generally looked upon as exceptions to the normal situation It is only the recent work on over-the-horizon radar that in- troduces radar transmission paths which are normally other than straightforward Hence persons familiar with radar a re usually not accustomed to the variety of transmission modes which are used in sonar In most areas the ocean can be divided verticaJJ y into two ms in regions on the basis of water temperature Starting at the surface and moving down- w-ard one usua lly encounters first a layer of water wose depth extends typically to one or two hundred feet rarely less than 10 or greater than 4oo in which the temperature is not particularly predictable and may vary rather erratically If strong winds have been blowing this upper layer may be well mixed with the resul t that temperature does not vaey with depth • _ SECRET ½ ' On the other band if mixing has not been strong then a fairly steep drop o temperature uith depth ma y occur Less common but not rare are cases of increasing temperature with depth and of inversion layers Beneath this surface layer one passes into the deep-vater regime Here the ocean is quite stable and the pattern of dependence of temperature upon depth is quite uniform from time to time and from place to place The tem- perature falls vith depth at first rapidly and then slowly approaching constant temperature at great depth The bowide ry between the two regions is often rather sharp and is calJ ed the thermocline These patterns of temperature versus depth are of para mount importance in any understanding of sonar performance The velocity of sound varies 'With temperature and with pressure and these 'With salinity which is usually less important determine the refraction conditions in which sonar propagation occurs Increasing pressure depth causes an increase in the velocity of sound of about 1 8 ft sec per 100 ft Decreasing temperature causes a decrease in the velocity of sound in the order of 8 ft sec per degree F Consequently near the surface in the upper layer the velocity of sound can increase 'With depth remain constant decrease Vi th depth or vacy in a more complicated pattern depending upon the interplay of these two effects Below the thermo- cline the velocity always fall with depth initially because the temperature term dominates the pressure term At a greater depth a few thousand feet the temperature gradient becanef small and the pressure term begins to control and belbv this depth the velocity increases with depth is a depth at which t he velocity is a minimum Hence there This is the a xis of the deep sound channel which 1s a 'airly permanent duct in t he deep ocean - S1 RET 0 L · · · • - _H'1Y' i o S-ECRET-- t In tbe neighborhood or the surf'ace these characteristics usually cause the sound propagation paths to be quite complex Negative temperature gradi- ents above the thermocline cause downbending and tend to produce a -s urface shadow zone This is the counterpart of the horizon shadow in radar but the sonar horizon may occur only a couple of kil oya rds from the source Positive temperature gradients or isothermal water above the thermocline lead to upbending and the consequent formation of a surface duct 1n which shallow targets may be detected at greater•tban-average ranges However these same conditions tend to produce a shadow zone at the depth of the thermocline 'With the result that a target below the thermocline may be poorly detectable Generally speaking sound which passes down through t he thermocline enters the upper region of the deep sound channel Sound waves moving above the a xis of the channel are bent downward those below are bent upw rd This duct traps the sounds and their intensity fa l ls off slower than the inverse square law If the sound -waves avoid surface and bottan reflections which tend to scatter and absorb sound and if the frequency 1s low enough to avoid excessive atten tion then sounds can propagate in the duct for hundreds of miles with modes J oss of intensity This is the basis of SOFAR and LOF AR These effects serve to illustrate why it is reaJ ly not possible to give a concise answer to the question of what range sons rs can achieve It is necessary to break the answer down into at least a few different cases Besides the cature 0£ the sone r itself the folloving variables influence the answer strongly _ ml-23ll l0--28-58 81 0 Kind of sonar platform 0 Speed of sonar platform 0 Depth at which radiator is placed 0 Water depth to bottom 0 Character of the bottom 0 Temperature structure 0 Depth of target There are combinations of these variables for which the sonar range is as little as 100 yd and there are others for which i t is hoped to achieve 100 miles with future equipment An average is essentially meanillgless The ray paths also help to illustrate the importance of tilting sonar By tilting the radiator up or down the sonar operator can change greatly the intensity of sound which arrives at diff'erent regions This introduces another factor into detection range calculations which should not be ignored When one attempts to estimate the range at which the probability of detection is 50 per cent the answer is dependent upon what the operator 1s trying to do In a tilting sysfem for example what tilt 1s he using to search with7 Tilt is oDl y one of a group of variables vhich enter into this question Others include the azimuth sector width over which search is conducted the speed of the search platform a od the range scale prf which is chosen An estimate of search rate capability which includes these f'actors is quite involved and a broad general treatment of the subject is nearly useless However it should be noted that statements of detection range frequently pertain to the characteristics of the sonar set when aimed opr irnaJJy at the target and t hey then do not include the ot her factors which inf'luence search rate It should not be ass lmed too hastily or example that a ship advancing · SECRET · a 3ll 10-28-5 8 82 across he ocean can search uni ormly a circle whose radius is equal to quoted values of sona de ection range It is relevant to the Polaris problem to not that re raction conditions are a minor consideration when the sonar angle of tilt is steep The sound rays are then no longer grazing the temperature layers and the bending of the rays is trivial except for precise f ire control Hence upward-looking and downward-looking sonars and fathometers work much more predictably than do search sonars If a surface ship can get into position more or less directly above a submarine and i f the sonar is free to ti t so as to cover most of the hemisphere below tb en the submarine finds i more d i 'ficul t to escape Hm1ever the surface ship is under these conditions hard put to keep up wi ch the submarine as it tWists dives and speeds up then it is maneuverability and speed which nable the submarine to escape rather tban intrinsical ly poor sonar performance A submarine chasing another submarine bas the advantage over a surface vessel that it can go up and do Wll through the temperature layers as its tarGet does Furthermore the chasing submarine can enjoy the same speed and maneuverability as its target Hence a nuclear subme rine equipped with modern active and passive sona r has a good chance of remaining on the trail of a target indefinitely once he has been vectored in and contact has been established Finally it should be noted that the importance of the temperature structure is appreciated by both submariners and Af3W orces and as much by the S U as by us It is standard practice in our Navy and presumably in the Soviet Navy for submarines and surface ASW forces t o make fairly frequent mee sureme uts of the temperature struct ure of the wa-cer the in strument used is called the batbytheI'I lograph i quent ly abbreviated to BT • RM-2311 lo-28-58 83 Hence it mIJ Y be assumed that both parties in an ASw problem know the temperature structure and atte14pt to optimi e their tactics with respect to it The foregoing discussion is a verJ abbreviate exposition of propagation paths as they a ffect sonars presently in operational use However although it is intrinsic in wb e t bas been said so far the emphasis has not been placed on propagation paths which underlie new developments now under way These new sonars look very promising and are eJ 'J ected to be in operational use 1n a few years To understand them it is necessary to consider more carefully the sound rays which curve dc m into the deep sound channel During lorld War II and even today such sound was lost for practical purposes except insofar as it contributes to long-range reverberation In sufficiently sba l J ow water or Vith sufficient dovnw rd tilt the sound hits the bottom where some of it is absorbed and some is refl ected The fraction which is absorbed may be quite high but that which 1s reflected moves upward and either hits the surface or simply curves back to the bottom Tha t which hits the surface is not reduced significantly by absorption but at the same time it is not reflected uniformly because the surface is not perfectly smooth The sound goes on bouncing off the bottom and surface being scattered to some degree in ea ch reflection and being absorbed in the bottom until bottom absorption scattering geometric divergence and attenuation consume it For existing operationa l sonars whose frequencies are generally above 10 kc and vhose pulse povers are typically on the order of 10 kw t he absorption attenuation and scattering reduce the useful signa J level so rapidly tb e t sonar raoges in shallow water are very poor Not oDJ y does the signal disappear into noise but it also must compete with severe reverberation RM-2311 1 8-58 84 It is clear that the processes of absorption and attenuation can be combatted by increases in radiated power Furthermore these processes and the severity of scattering from a rough surface can be combatted by lower frequencies Hence development has been heading toward high- power low- frequency sonars to operate by bottom bounce Such sonars seek to detect targets via these reflecting paths As a n example the LORAD program at USNEL which is only one of several of interest for bottan bounce is presently radiating 30 kw between 1 and 2 kc A staggered program of multiple-frequency pulsing is used to overcome the l im ited de ta rate of sonar and correlation techniques are used in the receiver The next development step will go to 200 kw and fUture plans envisage l megaw tt At best bottan-bounce systems must find their targets embedded in severe reverberation Tbe radar man can conceive the typical shal low---water probl em to involve using 300-mc radar to find a 5 or 10-knot target in an atmosphere only l 000 ft high with earth trees etc top and bottom ments are using sine wave - rm Present develop- and noise pulses with digital canputer corre- lation in the receiver to dig the target out of the clutter However it is apparent that the ability to find the target at all is dependent in large pa rt upon the frequency difference between the doppler from the target and the equivalent doppler spread of the reverberation Consequentl y the detection range especially in shallow water will probably always depend fairly critically upon target re dial velocity This is one of' many instances in which slow speed helps the submarine avoid detection There is · no basic difference between the use of bottom bounce 1n sballow we ters continental shelves and deep waters ocean basins except that in the former the number of reflections is greater with consequently grea te losses and shorter usef'uJ ranges However in de waters the use of bottom - - _ SECltEl - RM-2311 10-28-58 85 bounce leads up to and resembles the other main area of present development which is reconvergence- one echo ran0ing When sound curves down from the sur ace in deep water i finally passes the a xis of the deep sound channel and there starts to curve back up At a range in tpe order of 30 miles it comes back up to the surface layer and most of it probably actually hits the surface There is a sort of focusing effect which tends to bunch he rays back together again at this range so the soUild is said to reconverge in a zone at this range After surface reflection the sound heads back down again passes into the duct is bent up again forms a second reconvergence zone reflects again and so on Until scattering divergence and attenuation reduce the signal below useful levels there is a tendency for several successive reconvergence zones to exist For sources near the surface these are equal ly spaced about 25 to 30 miles apart and each zone bas an annular width of about 10 per cent of its range Various scattering processes occur both at the surf'ace and in the volume so the geometric regularity of r ay diagrams tends to be destroyed The first reconvergence zone usually shows up as a region in which the acoustic intensity is markedly higher tban on either side However scattering fills in the intervening regions and later zones become successively less pronounced blending into a fairly uniform distribution after about tbree zones In reconvergence-zone echo ranging the number and signal level falls ation orr or reflections is not great primarily because of geometric spreading a nd attenu- With sufficient puJ se power these can be overcome and so high-power systems are under developnent The LORAD program is primarily aimed at re- convergence with bottan bounce in a secondary role - •i' s 1l1T 99 - BM-23ll 1 8-58 86 Reconvergence-zone ranging like bottom bounce must combat reverberation When an annular region perhaps three miJ es across is returning echos from 30 miles away even a deep submarine is immersed in surface reverberation To discriminate the target against the reverberation background reliance is placed on relative Doppler discr1lllina tion It remains to be seen just how reliably a target may be detected at various radial speeds in the different zones Two other characteristics of reconvergence-zone ranging need to be mentioned One is that such ranging is dependent for its operation upon the re- focusing from the deep sound che nnel This is not al'WB ys as strong as one might wish and its characteristics are not the same in the Atlantic as in the Pacific There are those who expect it to be quite successful in the Pacific but not as good in the Atlantic Lastly it should be noted that re- convergence systems will probably g ve solid coverage out to a few kiloyards perhaps as much as 10 or 20 kiloyards in favorable circumstances but some- times much less then there will be a holiday in the coverage out to perhaps 25 to 30 miles at which point fairly re1iable detection under favorable circumstances may occur over a span about 3 miles wide Beyond this will be another 25-mile holiday where detection probability is very poor and at about 50 or 6o miles a band perhaps 6 miles wide vhere the probability 'Will be better but probably not really good When such systems become operational they will present some interesting problems to the operational people in the develo PD1ent of doctrines for optimum use of this pecuiiar pattern of detection probability It may turn out if the detection probability in the first zone is high enough in enough sonar conditions that a screening line of reconvergence-zone sonars in deep water could be spaced about 35 to 40 miles apart this range are for the present pure speculation • SECREl 100 Estimates beyond CAPABILITIES OF U S ACTIVE SONAR The estimates presented below of present and anticipated active sonar capabilities are ta ken entirely from e report prepared during 1956 end published during 1957 by the Committee on Undersea War are of the National Research Council However additional comments and information are included which are based in part on a series of recent visits to Navy agencies including OpNav BUShips USNUSL NRL and USNEL The active ranges presented in Table 2 are those for 50 per cent probability of detection of a re ndom-aspect submarine at 14-d b target s rength and are based on the following set of standard conditions unless otherwise noted o Deep water 2500 fathoms convergence zone paths e ist o Mixed surface layer depth of 100 ft o Surface temperature 50°F o Sea state 2 This situation represents an approximate average of conditions for the middle North Atlantic over the spring summer and fall periods During the winter the mixed layer depth increases to depths greater than 300 ft due to the higher wind forces and concomitantly higher sea states Platform A Convoy Escort Surface Ship 15 Knot See Table 2 Platform B Hunter-Killer Surface Ships 20-30 Knots This platform will have somewhat poorer performance than that shown for the first four convoy escort equipments It is doubtful whether either if-peterson s A Expected Active and Passive Sonar Detection Capabilities of Current and Future Platform•Equi pment Combinations NRC CUW 0241 April 1957 Secret - - s·Elrtllt BM-23ll tt28-58 • · • iii• lb· 1 · i fjl Table 2 PLATFORM A CONVOY ESCORT SURFACE SHIP '15 KNOTS Average Range for 50' ti Probability of Detection Transmission Path Kiloyard s Submarine Submarine Equipment in Layer Below Layer Near Surface SQ S-4 8-14 kc 4 5 1 5 8 3 one prototype fo ur years to fleet use 8 7 In development 7 years to fleet use 12 3 5 In development 7 years to fleet use 25 4 Research stage 10 years to fleet use 8-14 kc tri-beam s -4 8-14 kc tri-beam hull and 250-t't towed transducer SQ S-23 5 kc 2-4 kc sonar 2-4 kc sonar Bottom Reflection Path 2-4 kc sonar 1 In production one year to fleet use SQ S-4 Convergence Zone Status zone 57-63 zone 57-63 114-131 depends upon surface reflection loss Research stage 10 years to fleet use I one 10-30 depends upon Research stage 10 bottom characteristics years to fleet use I - - -- SECREir 10 2 RM-23J l lo-28-58 89convergence zone paths or bottom reflection paths can be utilized by equipments on this platform bece use of its high background noise In order to overcome the background interference a very large equipment appoxime tely 16 x 10 ft would be required which would introduce a large am ount of drag and conse- quentl y decrease endurance drastica lJ y sonar should give some improvement A well-shiel ded deep variable-depth However the basic limitation of sonar operated at high speeds appears to be flow noise which bas not been appreciably reduced to date Platform C Picket Surface Ship Slow This platform should be capable of carrying a very large eqUipment which could be towed if necessary to reduce the ef fects of high sea states and second convergence zones should be reached and possibly the third First Bottom reflection paths should provide ranges f'rcm about 10 kilcya rd s out to 4o or 50 ld loyards depending upon the smoothness of the bottan When surface ducts 250 f't deep or more exist mid-Atlantic winter ranges as great as 100 kiloyard s may be obtained on targets in the duct Platform D Coa s taJ Patrol Cra f't The SQS-9 J 2 14 16 and 18-kc searchl ight 100-ft variabJ e-depth sonar is a vaila bl e for this type of craft should be achieved against both deep and Ranges of about two kiJ oyards shalJ ow targets With a J a yer depth of about J 00 ft Platform E Airship Helicopter See plane or Hydrofoil Craft See Table 3 Platform F Explosive Echo-Ranging frcm Fixed-Wing Aircraft and Other Platforms See Table 4- Platform G Submarine See Table 5 RM 2311 10-28-58 90 3 Table PlA'IFORM E AIRSHIP HELICOPTER SEAPLANE OR HYDROFOIL CRAFT Equipment Average Range for 50 Average Speed Probability of Detection of Advance of Kiloyards the Platform Submarine Submarine _ Knots in Layer Below L er Status AQS-2 25-kc airship towed variable depth sonar 24 2 9 1 8 Under evaluation AQS-4 20-kc helicopter 70-ft dipped 11 l 9 J 3 In fleet NRL LOMASS-3 2-kc scanning Airship dipped in layer 35 15 3 5 Under development laboratory prototype by December 1957 NRL LOMA BS 3 35 12 3 2 6 Under development laboratory prototype by December 1957 2-kc sacnni ng helicopter dipped in layer SECRET· l fv-i 7 BM-2 3ll 10-28-58 9i Table 4 PIA ORM F PLATFORMS EXPLOSIVE ECHO-RANGING FROM FIXED WING AIRCRAFT AND OTRER VARIABLE WATER CONDITIONS MIXED LAYER 0-150 FT THICK Transmission Path Near Surface System 11 Interim11 Status l 5 5 10 5 2 vailable in ess than one l 3 y be avail- Vertical directivity in receiver to reduce bottom reverberation 10 5 10 5 Two hydrophones omnidirectional at 6o and 300 ft 1 5 5 5 10 5 3 5 5 5 7 5 Two vertically 2 directional hydro- 10 5 phones one shallow 1 5 5 one deep Total depth all Very deep source near surface con- and receiver d itions -12 000 ft 3 le 3-5 years y be availle 3 years y be avail- able 3-5 years 30 30 be avail- 50 50 ble 7-10 years When more than one range is given first number is for 50 per cent probability of detection second for 50 per cent probability under some conditions 50 per cent under others and third tor some improvement expected but degree uncertain · 10 ' S BM-23 ll lo-28-58 92 5 · Table PLATFORM G SUBMARINE Transmission Path Equipment Near Surface BQS-3 Single PJ atf'orm Operating Condition Average Renge for 50 Probability of Detection Kiloyards Target Target in Layer Belov Layer Status In fleet ping Submarine quiet in layer 10 HTC 200 Below layer SQS-4 8-14 kc Transiting noisy sbail ow 6 2 5 A few in fleet SQS-4 8-14 kc Transiting 3 5 5 A few in fleet 21 4 5 7- 5 noisy deep 5 Quiet shal low kc Part of integrated sonar proposed for 585 nuclear submarine Research stage 10 years to fleet use 5 kc Transiting noisy f shall ow Convergence Zone 5 kc Quiet Zone 56 5-63 Zone 56 5-6_ II Bottom Reflection 5 kc Quiet Zone 20-50 -11- · j#'c·RH IO o 16 3 5 Zone 20-50 II - - 1 - -t 1r i RM-2 ll I l0-28-58 SECRET' 94 Table 6 PLA'lFORl J Platform Depth fathoms t- - 500 DEEP VEHICLE REMOTE PLATF'ORM Average Range for 50' Probability of Detection Kilo vards Target Target Target Area Above Below at Covered Layer Layer 1000 ft sq mi 10 10 16 SJ Status NRL--Tests sched ul ed January 1957 Feasibility depends upon surface reverberation data urgently needed r ---- 15 15 20 5 175 24 5 24 5 30 450 33 5 33 5 39 5 1000 NRL--Funds requisitioned for 195e Feasibility depends upon surface reverberation data urgently needed The table applies to an upward looking sonar omnidirectional in the horizontal plane vhlch ms y be located at the depths shown The ranges stated are the horizontal radii to the outside of the annular search patterns of this equiJ llent when an isothermal mixed layer 200-ft deep exists No ranges are given for the inner radii of the annular search patterlls because of the lack of data concerning surface reverberation RM-2 11 lo-28-58 9 3 Platform H Bottom-Mounted Shore Very-long-range active deep-ocean surveillance systems are under consideration Too little is known about many of the basic parameters hovever to permit any significant predictions at this time It appears that ranges of 50 to 100 miles may be achieved by large fixed active systems in sba l lov coastal water during periods of the year when the water is fairly well mixed Platform I Fixed Buoys Such platforms in deep water can afford sonar performance ranging from a few kiloyards to very long ranges depending upon their size power and depth Communication to the monitor can be provided by cable radio or so- ns r links Certain applications of such devices appear quite attractive and are being investigated Fixed surface-looking buoys arranged in barriers may be the only practical method of providing coverage of some shallow coastal regions during periods when propagation losses are very high Platform J Deep Vehicle Remote Platform See Table 6 The following ai e a variety of comments on individual entries in the tabular data presented above In Table 2 the improvement in range between rows 2 a nd 3 for targets below the layer illustrates the influence of a surface layer In row 2 the sonar is mounted on the hull of a surface ship and so is above the layer In row 3 the surface ship carries a sonar radiator which can be put below the l ayer _Such variable-depth sonar VDS towed sonar has been tested but is rare in the operational forces Future modification will install this feature in the operational forces In this same table rows 3 4 and 5 show the anticipated benef'1ts of low frequency a nd high power but the -' - SE 1 RE f ·iT· t rlOJ -' tt J ij - V- • I 1 4 ·'· S·EC RE·T ·· Ii • influence of the layer is evident M RM-23ll 1 8-58 95 •j w t It must be emphasized again that the 25- kiloyard estimate even though by surface paths is for deep water Platform A presented in Table 2 is described as Convoy Escort Surface Ship 15 knots The Convoy Escort part of tliis description is really not significant the table applies to surface AStl ships at 15 kllots independent of their mission Platform B is deserving of note simply speeded up This may be looked upon as Platform A The remarks ma de by the NCR report are well ta ken Sur- face ships which move about at high speed are virtually useless when compared with slower ships the curves of self-noise versus speed climb astronomically above about 18 knots and at present there is no reason to foresee much change in this situation Hence S U surface search forces mu st obtain search ra te by numbers and not by speed Platform C probably deserves a place in a balanced mixture of ASW forces However 1n coastal waters it does not pose too serious a threat to a submarine because the submarine can avoid the picket and because even a picket ship does not enjoy a very good range in shallow -water Platform D ma y be looked upon as an inexpensive version of Platform A Inasmuch as the S U will presumably be hunting Polaris-carrying submarines in coastal waters it may be expected that such craft will be numerous in their fleet The building time for such era ft is much less than for full- fledged ocean-going destroyers so it is not at all impossible for the to acquire large numbers of these in a few years s u Hence large numbers of such PC boats might turn out to be the most potent threat faced by the submarines Once a PC boat makes a contact he can call in his big brothers to maintain the contact and to make the kill - - -- 'rSEiR6l i 109 - - RM-c 3ll 1 8-58 96 Platform E Table 3 is a handy adjunct in a mixed ASW force because it can move rapidly into an area of suspected contact and there help to establish the contact However even these aircraft move slowly in terms of the distances involved and in terms of the speed with which a submarine can break off sonar contact ating area Hence such crai t require basing rather close to the oper- As things stand today the s u does not have such bases near the potential Polaris operating areas except for the Barents Sea The appear- ance in the Russian fleet of numerous small aircra1't carriers would probably signal the development of such a basing capability for the Norwegian sea In any event such sonars are intrinsically limited by the weight size and pover capabilities of the platform and so cannot be expected to show great range improvement in the foreseeable future Platform F Table 4 bas not we understand lived up full y to the expectations of a few years ago Inasmuch as an expl osive source denies the use of some valuable signal processing schemes in the receiver this is perhaps not surprising In any event where three ranges are listed for each set the first number is probably a better one to contemplate than the second or third Platform G Ta bl 5 is the potent one on its own merits As mentioned previously the submarine can dive in and out o f the thermal structure as his target does if nuclear it can maneuver and speed up so as to remain on the tail of the target To do these things the pursuing submarine must use active sonar wid so is vulnerable to attack himself' but at least he cannot so readily be shaken off the trail Except for the fa ct that these values per- tain to deep water onl y the various estimates in Table 5 are probably the most nearly conservative of any given in the NRC report I · fklfEJ' 110 ''i -· BM-2311 l 8-58 97 Under Platform r the word 11may 11 should be presented in boldface red type No evidence bas been found to support the 50 to 100-mile estimate given here it appears to be pure spect lation based upon a 300-cps-to-2-kc research program which has so far not yielded such esuJ ts In many respects Platform it is an aJ ternative platform I does not involve sonar problems as s'ltch However it may be noted that buoys a re par- ticularly vulnerable to several countermeasures Furthermore they often re- quire a friendly sho e which the S U does not have in most of the areas of Outside the 3-I lile licit it is qui e possible that various nations interest might sweep the buoys up either accidentally or as hazards to navigation The remarks in the last coJ Uiilll under Platform J Table to this question 6 hold the key This matter of the competition of surface reverberation with the echo and the extent to which doppler discrimination can improve the echo reverberation ratio was discussed above Unt'ortunately the NRC report fails to append this remark to several other line items where it is also warranted In any case this platform is of limited interest in the Polaris context because of water depth On the whole the estimates presented are more relevant to the classic anti-submarine var 1n'defense of overseas transport than to def'ense against Polaris 'l'wo f'actors particularly lead to this comment the choice ot water depth and sonar conditions and the presentation of 50 per cent probability ranges The contemplated use ot PoJ aris undoubtediy involves operation in the North sea ong the Norwegian Coast and possibly in the Barents Sea AJ l these -waters are shal l ower mostly about 100 fathoms rather then 2500 fathoms and the temperature structure is probably poorer than that assumed 1n the NRC -eport Those instances in wbich the NRC report estimates l ong ranges by SECR'El 11 - - reconvergence or by deep-water bottom bounce are inapplicable in tbe shallow water Even the estimates of ranges by near-surface paths are on the optimis- tic side in these shallow Waters because of temperature structure and bottom reverberation The main body of the Norwegian Sea ls a bout 1500 fathoms deep and the deep-vater conditions assumed in the NRC report will be met to some degree However in this area the deep sound channel may be poor because of the effects of ocean currents and reconvergence may be poor Furthermore the temperature structure above the thermocline vill probably be poor much of the time In the Mediterranean extensive areas of deep water are found but poor temperature conditions may be expected because of strong surface heating and rather poor mixillg Even in the Mediterranean a Polaris-carrying submarine is likely to spend most of its time in sballow coastal waters and among isl ands In such cases the remarks above concern- ing the shallow northern areas apply here as well Estimates of 50 per cent detection probability range are useful in eJ l circumstances however they are perhaps more indicative of the operational problem 1n a protracted var of attrition than they are 1n a sudden-death all-out strategic nuclear liSI' For the latter 50 per cent probability ranges should be supplemented by 90 per cent probability ranges because such high values more nearly- characterize tbe problem faced by the defenders Because of temperature and bottom cond 1tions 1 t is not uncommon to encounter 50 per cent probability ranges of' one or two kiloya rds and 90 per cent probability ranges of zero yards That is in many sh allow water areas the defending forces especially surf'ace ships and shall ow dunked sonars may never have 90 per cent probability of detection because of temperature structure and bottan conditions Such an area is that off B l 1fax and cooditions off the Norwegian coast miglit well be similar I • ' · Ste REt · l'L - -·· u ·-SECRET I 10-28-58 -99 1- • • The NRC report data al so tacitly assume that the submarine tails to execute some of the evasive maneuvers which a Polaris-carrying nucl ear boat could and probably would use Aside from countermeasures which are dis- cussed below the boat can turn tail aspect on his pursuer thereby reducing his echo some 4 or more db below those assumed here and thereby knocking the bottom out ot 90 per cent ranges for many equipments Further the boat can reduce speed to very tew knots thereby nearly eliminating the doppler dif'ferential whereby the ASW vessel se·eks to sort him out f'rom the reverberation In the shallow seas up to perhaps 200 f'atboms the boat can simply lie on the bottom To discriminate the boat fran other objects on the bottom then becomes very dif'f'icult if the bottan is at all rough anc1· rocq the boat blends in and only a high-resolution map of the bottom can disclose the boat by its shape FinaJJy ii the defender 1s not well-equipped with low-frequency passive sonar in the ecmbat area a nucl ear submarine can if he chooses simply run away f'ran surface ASW forces These latter cannot make better than about 15 knots and preferably much less Vithout sacrificing detection range seriously The nucl ear boat can easily af'tord to go faster if he is reasonably sure he will not be tracked on passive gear The only existing active AS l sonar develq mient program which is not reasonably well covered in the NRC estimates is the Colossus I program at USNUSL This is a bottan-mounted upward-looking chain ot active sonars tor use as a barrier line in shall ow water Such sonars are essentially inverted fathometers and they enjoy the same relative treed om from refractive effects hence their operation 1s quite reliable from a sonar viewpoint reverberation-limited They are a submarine can be detected reliably only at ranges shorter than tb e range to the surface A range gate is used to exclude the SE RET J l ' 311 lo-28-58 100 surface return and this serves to establish the mjnimn1D spacing between radiators in the string The gap in coverage mid-way between t-wo radiators and near the surface must not be big enough to permit a submarine to sneak through The USNtJSL program has determined that in- 250 f'athans the maximum permissible spacing between units 1s 200 yards in shallower water it would be correspondingly less the interval f'rcm The Colossus I progmm has used frequencies in 16 to 26 kc with 3 watts radiated which gives 34 db signal noise ratio in state 6 sea noise 500 such units 25 mil es They believe they can put up to on one two-conductor cable cessing would be provided at the transducer Automatic data pro- It is USNUSL' s rough guess that at 20 units per mile the cost would be $75 000 per mile plus installation costs plus shore station costs plus operating costs They- note tb at vater currents might make troubl e in laying the equipment pack ice on the shore would al so make trouble If' a suitabl e friendly shore -were availabl e then systems such as Colossus I would be quite feasible and reliable though costly If permitted to operate as planned they would probably be nearly perfect if' means were provided to sort out shallow submarines f'rcm surf'ace vessels The sub- mariner's response to' such a system would involve countermeasures Apart fran acoustic countermeasures one ef'f'ective countermeasure woul d be to drag the equipment up w1th hooks as soon as it is laid Perhaps the subtlest trick would be to drape acoustic covers over a tev of the units so that they appeared to work but never gave any e hos Si nce the units a re active it would be easy to find them and such covers could be put 1n place by UDT men Between these two extremes lies a whole spectrum of countermeasures some of which are discussed below · ·Sl C R'i li · L 11 3ll 10-28-58 l Ol PASSIVE SONAR In recent years the great hope for the ASW problem has been passive sonar that is lov-frequency 11 stening equipment in deep water to hear the noise radiated by submarines By using long l nes of rather silllple receiving units it is possible to obtain considerable directivity even at low frequencies e •g 100 cps • The numerous receivers are strung eJ ong a multiconductor cable so that each output is brought separately to the beach There phasing net-works are used to make steerable beams or groups of f'ixed beams from a singl e array of hydrophones Bearing accuracy of 2 deg at wavelengths of 50 ft is typical performance for existing gear By tri- angulation two such arrays can now yield a position f'ix w1th typical accuracy of about four miles radius this 1s good enough for surf'ace active sonar to finish the Job with a modest amount of search By using low frequency such shore-based deep listerdr l g arrays can achieve detection and tracking at ranges of hundreds of miles because of lov attenuation and duct propagation in the deep soUild channel It is im- portant to observe that it 1s only in deep water tbat such l ong ranges can be achieved In she U over vaters bottan absorption 8Ild mul tipl e scattering reduce the range drasticall y Much the same techniques which are used 1n deep-water bottom-mounted arrays can be used in shall ow water and in small er arrays carried aboard ships notably submarines In shall ow water as noted above ranges are perforce less under otherwise similar condi t1ons Ranges of ship-mounted gear are also less partly because ot interference f'rom own-ship noise but also because the array 1s smaller Much effort is now devoted to quieting the new attack submarines so as to improve their listening ranges however it should alva ys be possi'bl e f'ar bigger bottom-mounted arrays to give ap- preciably longer range · JUJllE T II SE CR RM-23U 10-28-58 l02 In addition to the ship-mounted medium-size passive an-ays there are also available for use small expendable air-d roppable passive sonobouys These listen for submarine noises and send the signal to aircraf't by radio Such bouys are much too expensive for continuous large-area surveillance but they assist a hunter-killer group in establishing initial contact and in re-establishin8 a lost contact U S f'leet-type submarines can travel only about 150 miles on batteries this at low speeds at high speed the distance is much less Such sub- marines must operate their diesels at points in the- ocean not more than 150 miles apart Consequently in an area under passive sonar surveillance such a submarine stands a poor chance of transiting the area undetected Actually even this statement must be moderated because such a boat can reduce the likelihood of detection quite a bit by running slovl y on his diesels and or by going on the surface The listening arrays which can yield such long ranges against snorkeling submarines can yield comparably- great ranges age inst noisy nuclear boats e g Nautilus Furthermore the ranges are quite long against high-speed boats even if they are otherwise fairly quiet But against slow boats and against ' quiet ntclear boats the passive detection ranges fall to val ues comparable to active sonar range or even less For the foregoing reason the vulnerability of the Polaris weapon system will be cri ticaJ ly dependent upon the ability of the submarine to be quiet This is probably the most critical factor in the whole problem o-£ Polaris vulnera bili ty because the S U will not f'ind 1 t diff'i cult to track noisy boats On the other hand they will find it very difficult to detect quiet boats ·sECREr 110 CAPABILITIES OF U S PASSIVE SONAR The material presented below is taken from the same National Research Council report that was used as a source of information on active systems The comnents made there concerning assumptions etc apply here as well Platform A Submarine Slow and Medium Speed See Table Platform B 7 Shore-Based Aircraft Sonobuoy and Submarine-Mounted See Table 8 Platform C Picket-Ship Very-Low-Frequency Systems It will be desirable at times to maintain surveillance of ocean areas from surface picket ships rather than from shore based install ations or from airers ft Several very-low-frequency passive systems have been suggested for this use and are briefly described in the following para graphs Bottom-Mounted Arrays Experience in conducting acoustic survey operations bas shown that a ship can stream to an eight- or ten-mile length of cable terminated in hydrophones on the bottcm for considerable lengths of' time and under fairly severe l weather conditions Both broad-band and narrow-band B Dalyzing equipment presently available for shore based use or under developnent for airborne or submarine use could be adapted for use on picket ships Such systems wi tb about eight hydrophones in deep water might be expected to give a reliable range of the order of 100 miles on a snorkeling or cavitating submarine To reduce the pOssibility of attack by a veey quiet submarine smaJ J explosive charges can be thro Wll periodically to check 'for echos both vith t he bottomed hydrophones and with an overside hydrophone · - SE6R61ir 117 a Table 7 PLA'IFORM A f 'r f SUBMARINE SLOW AND MEDIUM SPEED Vl X Maximum EquiIJllen L c BQR-3A 5-ft line hydrophone Snorkeling in dome trainable u s or cavitating any type propulsion Quiet c - OQ Plat form Operating 'fype of Target Condition a Recorder Aural Detection Classification Range Range Kiloyards Kiloyards Patrol Quiet X 18 13 kn X 4 Patrol Quiet X 2 5 Status About 30 in fleet Primarily a fire con l rol son a r Wi t h bearing a ccuracy-a 10 in A'IF If fi tted wit h a bearing recorder detect on performance would be al mo s t equal t o BQR-2B --1 QR-2b and Bearing Recorder -4 kc Recorder 0 3-15 kc ural approximately 6-ft I iJiameter circular arr y r 48 3-ft-high lines Snorkeling u s or Patrol Quiet cavitating any type propulsion 13 kn Quiet shallow BQR-4a and Bearing Recorder Snorkeling 10 x 20- ft conformal array of U S or 8 -ft-high lines o 6-4 8 kc cavitating recorder 15-4 8 kc aural 110 18 13 4 First product ion equipne t now installed Product n equipments for mos 1 of t e fleet contracted for - 00 ' Patrol Quiet 10 Patrol Quiet 16o 30 2 5 any type propulsion 13 kn 20 9 Quiet shallow Patrol Quiet 17 9 Approximately 8 in fleet few Will have bearing recorders o t hers will ge t them A ConLinued c-- n a ' 1 - Table 7 Cont'd Equipment H'l'C 200 -5 x 7-ft searchlighL Lruinable Platform Operating Type of Target Condition Snorkeling u s or caviLating any type propulsion Quiet Shallow c Q _ _ Maximum Recorder Aural Detecl ion Classification Range Range Kiloyardo Kiloyards Patrol Quiet X 18-30 13 kn X 4 Patrol Quiet X 2 5 S t atus One prototype JusL evaluated Future uncer tain Also provides single pins echo ranging and di rec io nal communication c-- n - l a rn - ---r 36 ft x 24 ft conformal array of spots one row high 0 5-2 kc recorder 0 15-5 kc aural c · -- ' 8-fL diameter Cylinder 4-ft high 1-2 kc recorder 0 3-10 kc aural Snorkeling u s or cavitating any type propulsion Patrol Quiet 13 kn 18o 11 50 -3 Part of integrated sonar proposed by USL for 585 nuclear boat 1958 building program IC l 'I - - f '1-' t Quiet Shallow Patrol Quiet 12 Snorkeling u s or cavita Ling any type propulsion Patrol Quiet 170 48 16 9 Quiet Shallow 4 13 kn Patrol Quiet ' Part of integrated sonar above primarily designed for active deLecLion a t 5 kc intermediate and sho rt range passive tracking an d fire control canno use LOFAR f b'f V1 Con t inued Table 7 Cont'd b I °'ii Equipment PUFFS three equally spaced 6-rt lines on 250f'l base line 0 2-8 kc Platt'orm Operating Type of Target Condii ion Snorkeling u s or cavitating any type propulsion Patrol Quiet Maximum Recorder Aural Detection Claosification Range Range Kiloyards Kiloya rds 10-15 for range determination accuracy about 2 per cent or range 00 Status Passive ranging system Breadboard model has had limited sea t ests by NOL · c-- NOTES - C V 0 · 1 2 3 Localization by passive equipment s about 2° BQR-2b--Automat1c target following will provide bearing accuracy of 0 25° on noisy target at 12 kiloyards on patrol quiet platform B -7 BTL described in LOFAR sheet 1t 1s proposed to use a LOFAR analyzer vi th this equipment vhich may pennit classification at recorder i'de t ection range when platform is at patrol quiet - - r-r t -rw- ' i · r Table 8 · PLATFORM B SHORE-BASED AIRCRAFT SONOBUOY AND SUBMARINE-MOUNTED VERY LOW FREQUENCY PASSIVE SYSTEMS Platfonn c _ c- f'J G Water Depth fa thoois Type of Targe t Type of Analysis Detection Range miles Localization Classification Status Shore -based deep arrays 1000 Snorkeling u s Narrow band LOFAR l00-4oo1 t5 20 2 Good but not Operationa18 100 per cent6 Shore-based deep arrays 1000 Low speed Snorkel British Narrow band LOFAR 75-300 f5 Good but not Operationa18 100 per cent6 202 a C'-11 C'- 1 - Shore -based deep arrays a 1000 J J High speed snorkel or battery British Narrow band LOFAR 75-4oo3 $ 202 Good but not Operat1ona18 100 per cent6 ·• • I' Shore-based deep arrays 1000 High speed nuclear Narrow band 200-1000 202 Good but not Operational 100 per cent6 J 202 Good but not Opera Lional 8 100 per cent6 tS LOFAR NAUTILUS Shore-based deep arrays 1000 Low speed nuclear Narrow band 10-100 LOFAR Quiet battery -5 Good but not Operationa18 100 per cent6 lf b X Continued Table 8 003 ConL'd I f ro N Platform Shore-based shallow water short arrays Water Depth fathoms 100 O W Type of Target Type of Analysis Snorkel U S • Narrow band Detection Range miles Localization Classification 20-50 broadband 50 Estimated 0 Status Good but not Available 100 per cent6 1958 4- 100 - ' 1 '-1 Quiet battery Narrow band broadband 1-10 50 Good but not Available 100 per cent6 1958 __ _ • Narrow band broad band Good but not Under study 100 per cent6 r j -' ii Narrow band broad band Good but no t Available 100 per cent6 1958 Estimated • i •I In - N p-- Shore-based very deep water arrays 2500 Note 4 tJ rB Shore-based 100-1000 medium dep t h arrays Note 5 ' Aircraft sonobuoy 1000 Aircraft sonobuoy 1000 Snorkel Cavitating Narrow band broadband 30-100 Narrow band broadband 20-4o 10° Good Product ion 1958 10° Requires sur- Production face observa- 1958 tion listening Aircraft sonobuoy 1000 Quiet Narrow band 1 2-2 broad band7 Estimated Good 0 roduction 1958 Continued ·- __ - C-J Table 8 Water Depth fathoms Platfo nn c » a ·'·t Aircraft sonobuoy 100 Aircraf't sonobuoy 100 Aircraft sonobuoy 100 Type of Target Snorkel Cavi ta ting· Quiet Cont'd Detection Range miles Localization Classification Type of Analysis Narrow band broad band7 10-' o Narrow band broad band7 10-30 10° Narrow band broad band 7 1-5 10° 10° Good Status Production 1958 Requires sur- Production face observa1958 tion listening Good ' ' l' l l i 1958 Submarine quiet condition Production c a 1 Snorkel ' Narrow band broadband 30-100 20 Good ' 'i ·-- r ' 'i BQR-7 Experi mental Model ll Submarine quiet condition --L • f Y 2 i ifJ f- Cl - t-l - l • 3 ' · Cavitating I I Narrow band 10-50 broadband demodulation 20 Fair ' BQR-7 Experi mental Model I A DOID ra I---r-±- lof 200 miles is enerallv used 'J1hPrP- i 9 A AmA11 AAClnna1 ro --lo -t-- - - -- - a difference between areas of the ocean At 200 miles from each of two or more stations it is approximately a circle of 4-mile radius By changes in propeller and fin design the blade and shaft lines can probably be greatly reduced thereby cutting the high speed snorkel range to 75 to 200 miles and the high-speed battery to a much lower figure Continued I I ' J JI O Table 8 Cont'd Fl I O' W NOTES Cont'd 4 Better ranges t han deep arrnys for quie t targets but poorer ranges on noisy target s 5 Ran$es 01 co intermedia te between those of deep water and shallow water arrays 6 The addi t ion of an ideal broadband bearing analyzer to the narrow band analyzer should yield an improvement in classification 7 Can be combined wi h explosive echo ranging to improve dete ct i on probability localization and classification ·· 8 A pr ototype broad band space correlation sys tem SIGMA for use with existing SOSUS arrays has been evaluat ed a t Eleut hera miles See USL Report No 308 Range on ca vita ting submarines 100-200 c -- - C l - Sa t ura tion Saturation random shipping well be problem in peacecime In wart ime '1th controlled _ - shipping saturation by targets may not be a problem if sonobuoy equipped aircraft a r e available to examine 1 'J1 in succession all targets in a given beam C M EN'l 'S by J may a j it ure Possibili t ies Range i ncreases are questionable as improvements in detection capabilities may be lanced by quieting of future submarines t ' Jamming Decoys Jamming by the enem y may be feasible Decoys may be feasible and would contribute to the saturation problem Interfering targets will cause more trouble to 2-hyd rophone CODAR than to SIGMA but a system combining the best propert ies of both should be possible c C ' t 'i RM- 2311 10-28-58 ill Floe ting Array As an extension of the sonobuoy principle a small amount of' work has been done with floating arrays In one l roposaJ hydroplanes a re mowited on the spokes of' an umbrella-like structure about 50 f t 1n diameter which in turn is suspended from a buoy ship can be provided Either a cable link or a radio link to the 'Ihe ana lyzing equipment vould be similar to tbat used for the bottom-mounted array This system would el so be expected to have a range of about 100 miles on a snorkeling or cavitating submarine the bearing accuracy would probably be less than that of the bottom array be used 'W'ith small expl osive charges for ecbos It could also This system has the dis- advantage of drifting unl ess an anchor can be devised it has the advantage of permitting the picket ship mobility for evasion or attack if a radio link is used Ship Sonobuoys Either short-life or long-lif'e sonobuoys can be used singly or in pairs The characteristics and analyzing equipment would be essent1aJ l y the same as the e ircraf't equipment but simpler than the f'loating array Handling would al so be simpler but t1te expected range on snorkeling or caVitating sub- marines would be only about 50 miles Again explosives could be used to help detect nearby quiet submarines The sonobuoy system requires little special-bandling equipment on the ship and therefore can be quickly installed on any vessel capable of' maintaining station Conclusions These data are as complete as they could-be made within the limited period of preparation Predictions of perf'o rmance in other propagation situations -wou ld be very desirable and sboul d include deep mixed layers · shallov depressed chanoel s intermediate depth r -1000 f'athoms and RM-2311 10-28-58 112 shallow water _ 100 fathoms It woUl d also be worth while to establish a mutually acceptable set of representative propagation conditions to serve as a basis for canparison of various sonar platf'orm-equipment combinations Fewer comments are needed at this point than were appended to the NRC data concerning active systems This is partly because the data speak f'or themselves if' all data relevant to snorkeling submarines and high- speed submarines are ignored then one can pretty well inf'er the situation as it would pertain to a quiet nuclear boat AJ ternatively one can see in these tables the detection and tracking ranges which the S U might achieve by passive sonar against noisy boats further comment Row 5 of Table 8 is singled out for The range of 10 to 100 miles listed for shore-based deep arrays against low-speed nuclear boats 1s at least highly misleading if not Just plain wrong Perhaps this ·estimate is applicable to the Nautilus which is an exceedingly noisy boat such ranges will be It shoUl d not be construed from this that obtained against quiet low-speed boats A far better estimate for that case is show in the f'ollowing row of Table 8 qUiet battery boats t to 5 miles Between these tvo 11m1ts 1 it might turn out that is a better estimate than The comments appended in the NRC report deserving ot more attention against 5 11 • to Table 8 are well taken and This 1s the subject of the following paragraphs i0NAR COUNTERMEASURES AJ thougb all sorts of active and passive sonar countermeasures were employed during World Warn it is only rarely that one finds countermeasures brought into a discussion of the potentialities of a sonar weapon system 1n this respect the whole field of sonar is less advanced than radar where a universal consciousness of count ermeasures exists SV IED Not that the techniques RM-23U l 0-28-58 ll3 and deVices for sonar countermeasures are l acld ng rather the absence of this phase of the problem from sonar system anaiyses sometimes lends an air or un- realistic optimism to forecasts of capability against a skilled and determined enemy Polaris submarines could derive much protection fran well-used count er- measures they should be incorporated in the weapon system and they should be accounted for in an estimate of vulnerabil ity There are several techniques and devices which can help a submarine avoid detection entirely Probably the most important ot all is simply to be quiet and this has been discussed above However the quietest boat faces some chance albeit small of being found more or less by accident One way to diminish this cha nee markedly is by painting the submarine w1 th a sound-absorbing coating DuriDg World War II the German Navy developed absorbing coatiDgs there is some controversy over their actual effectiveness and over the absorption mecbanism in the material but there seema to be little doubt that some absorption was obtained In this connection it must be emphasized that as little as 3-db echo reduction can have drastic effects on detection probability especially in shall ow -water where reverberation limits the detection range severely Af'ter the var the U S Navy supported a development program at M I T to carry on fran the German start By the late 194 1 s the M I ' program had produced a coating vhich in the laboratory yielded about 10-d b or more echo reduction over the temperature and pressure ranges of interest to a submarine 'lllat coating was more effective against the sonar frequencies then 1n use e g 24 kc and woul d undoubtedly' have given poorer absorption at lower frequencies The M I T laboratory- tests vere sufficien promising to lead to a full-scale trie l at sea and the U S S Cubera was coated Project Mystic The RM-231 l 10-28-58 U4 necessary clean metal surface was not obtained with the result that large patches of the coating failed to adhere and washed off shortly after the Furthermore the material laid down on the Cubera ve s Cubera put to sea demonstrably not that prescribed presumably because the workmen were not sufficiently skilled and trailled duction in the trial The net resul t vas little or no echo re- This event perhaps coupled with a basic question as to the extent to which U S submarines as their mission was then conceived would benefit from echo reduction led to a widespread loss of interest in the program It would appear that the value of such a coating to a Polaris boat would be so great as to justify a very sizable program aimed at producing a practical coating The goal need not be very large absorption although this is certainly desirable the goal should include useful absorption at low frequencies e g down to l or 2 kc • Above all the goal should be practicability there is no reason to suppose that a lov-f'requency coating need to be so thick as to be im practical and there is no reason to suppose that a coating cannot be bounded tightly to the hull by routine careful work in a Navy yard It should be noted that the USSR did not suffer the dis- appoint ment of Project Mystic and so may not be deterred from developing such coatings for Russian boats The old NAC and NAE beacons and their various kin are sonar noisemakers which a submarine can eject to jam enency- sonar parts of radar noise and sweep Jammers They a re the counter- They vork to sane degree and help a submarine to break off sonar contact once his presence in the area is certainly known To work against the new high-power low-frequency sonars bigger and more costly devices would be needed Such a development is certainly possib1e its worth voul d require car ul system analysis · JtSEti RB1tltU BM-23ll l0-28-58 ll5 Presumably if such noisemakers have a place in the scheme of things it must be to break off contact by a taili Dg S U boat during peacetime If nuclear- varhead ASW weapons were employed such ejected noisemakers would be of small help because of the large lethal radius A different family of noisemakers could be employed by U S boats to jam Soviet fixed sonar installations such as bottom-mounted or buoy-mounted active or passive systems Fairly cheap battery-operated noisemakers could be planted close to such arrays It would probably not cost the s u more to disable the noisemakers without damage to their own systems than it would for us to place them by air drop or by ejection from torpedo tubes Such noisemakers with a useful life of' a few weeks might be laid in times of international tension as part of a low-level alert Homing torpedoes both active and passive are in use These can of course be used as defensive ordnance with considerable effectiveness A submarine is not helpless against attacking ships because the submarine can usually detect a nd track the surface ship long be ore it is itself' detected However homing torpedoes can also be used against bottom-mounted active sonars The exchange ratio can be quite attractive and it should be pos- sible to deter the S U from em placing sizable sonars in international waters Dragging or cutting the cables to 1 ixed installations has been mentioned previously This is really not very difficult especially if the location to drag is reasonably well known by virtue of watching the installation go in U D T swimmers can be lawiched from and recovered by a submarine equipped with widervater sleds such men are quite mobile In shallow waters they can explore the bottom to find hostile installations cables or disable equipment If They can cut More subtly they can move equipment from place to place or rotate it so tbat it gives f bearings They can cover RM-23ll l0-28-58 1 16 it vitb sheets of foam rubber and so put it out of business U D T men can also inspect their own submarine to discover limpet bombs this would seem to be a necessary defensive move especially in the Mediterranean where limpets might otherwise be very attractive to the S U If Polaris submarines plan to lie for appreciable periods in shallow waters off the Norwegian coast they might help themselves by ejecting from their tubes simple battery-operated echo-repeaters A bevy of such devices strewn about in shallow waters would give the S U forces a collection of false submarine targets to investigate and perhaps attack It should not be unduly difficult to construct a battery-operated device which emits a line spectrum roughly resembling the LOFAR signature of a diesel engine A series of sharp low-repetition-rate pulses is needed be used to deceive or to saturate These could long-range low-frequency passive sonar Friendly surface shipping can be sailed around in the vicinity of lowfrequency passive arrays These ships can be made to put out sizable amounts of noise a freighter running light with a bent propeller shaft is especially good at this and so to render the passive array nearly useless Of course anchoring the freighter doing a fair amount of hull riveting and then dragging the anchor acro s the array can be helpful additions to such a scenario Surface shipping even hostile vessels can be used to penetrate a barrier A submarine can run under a surface ship or bang on in his wake with only moderate difficulty and it is very difficult for search forces to find him there Unless s u destroyers are equipped with exceptionally good sonar a dari· ng submariner could even tag along Wlder a destroyer returning to port At night during peacetime a submarine can run on the surface close to merchant ship ing with very slight risk of detection radar is not likely to find him t -n- - - • ·iN ' trt 1· -· Dt llllfl l l M In that position RM-2311 10-28-58 ll7 At night a submarine can run close to a shore on the surface with small risk of detection especially if he exercises modest caution to detect unfriendly radar and sonar early enough to dive and lie on the bottom In nearly all conditions a submarine is safest at snallow submergence and he is much safer in shallow coastal waters among islands This tactic with quieting with an echo-reducing coating and with a few countermeasure devices should make a nuclear submarine nearly undetectable ALTERNATIVES TO SONAR Inasmuch as sonar works as poorly as it does one may well inquire why it is the predominant anti-submarine detection method The answer is simply that all the alternatives are even less versatile and usef'ul Though sonar ranges are short all other techniques offer even shorter range and most have additional limitations Nevertheless there are alternatives and these must be anticipated in the defense of a Polaris-carrying submarine MAD Magnetic Airborne Detector or Magnetic Anomaly Detector gear carried in low-flying aircra can detect a submarine by the disturbance which the submarine's steel hull makes in the earth's magnetic field In i the long run the submarine could counter this device by degaussing or by the use of non-magnetic steels but these measures are not now contemplated in the Polaris program The detection range of MAD is only about 1500 ft maximum and so the gear is chiefly useful in closing a narrow channel or in localizing a contact established by other means Magnetic loops•-that is cable loops on the bottom--can also be used to detect the presence of the magnetic disturbance caused by the submarine Such loops are of quite limited applicability because of the need for a friendly shore because they only work i n fairly shallow water in areas of -· t I• 1 RM-231 l 1 0-28-58 11 8 small natural magnetic disturbance and because it is impractical to use them in areas where water currents are strong There is at present a development program Project Clinker which uses airborne passive infrared gear to detect a trace the passage of a submerged submarine on the surface caused by There is not much doubt that tbe trace is weakened by deep submergence a nd by slow speed It is not yet clear how soon a f'ter passage the trace appears nor is it yet clear that identification of the trace can be sufficiently reliable At best the surface tends to be cluttered by windrows and by traces from surface ships On the other hand it may turn out that a nuclear boat leaves an especially strong or characteristic wake because of the large amounts of heat vented outboard It is not now appropriate to go beyond the foregoing remarks because an evaluation program for Clinker is under way and the results have not yet been reported to us The submarine will be especially vulnerable to covert attack when in and when leaving port At those times it would be f'airly easy for covert U D T men disguised as sportsmen for example to attach devices to the hull of the boat This would involve a certain amount of risk but it should not be assumed to be an unacceptable risk especially if it is known that the submarines fail to inspect themselves at sea Various harbor defense devices to protect against free sw immers exist but it would be foolish to suppose they cannot be penetrated The devices could be lim pet bombs mentioned previously but they might also be noisemakers or lights or dye-markers which would facilitate detection when set off by a time clock Self-inspection at sea would seem to be the surest defense against such devices and is just one more mi ssion for a team of U D T men aboard the submarine SEC RE l • -· t RM-23ll 10-28-58 ll 9 MINES Unlike all other major naval powers in recent years Russia has a naval tradition and histol 'J of mine warfare Mine warfare is regarded as one of the main branches of the Russian naval service and career officers serve their stint in the field as a matter of course Russia is known to have a large stockpile of thoroughly modern mines and has used them in the recent It must be assumed that Russian planners will at least consider the past use of mines in defense against Polaris Naval mines can be grouped in two main types moored mines and growid mines Moored mines are buoyant and are held at a preset depth by an a nchor a lock can be used to hol d them down until it is desired for them to float up to position Ground mines l ie on or in he bottom they need not be buoyant and so can carry a heavier charge 2000 lbs is typical as compared with 600 lbs for moored mines All mines could carry nuclear charges Modern mines are highly devel oped when laid gently and with care they are reliable They can be laid by submarine by surface vessel and by air either with or without a parachute Moored mines once they let up to depth are relati ely easy to locate by high-resolution sonar although search rates tend to be low and they can be swept by conventional m nesweeping techniques which cut the anchor cables Ground mines are exceed- ingly hard to locate for all practical purposes this remains an unsolved problem despite a great deal of development effort Furthermore no satis- factory sweeping methods a re available for use against a sophisticated gTound mine Mines in present stockpiles can be routinely outfitted with of the following gadgets sEBlff' u u I an y mixture RM-23ll 10-28-58 l2Q o delayed rise to depth moored mines preset at time of laying o delayed a ' llling usually up to 1 year preset at time of laying o ship counter which simply counts down one digit from a preset number every ti me the mine would otherwise have gone off o magnetic signature o acoustic signature o pressure signature Among those developed but not usually used are optical sensors vibration pickups and cosmic ray background sensors no doubt still others exist Not all of these gadgets would be useful specifically against Polaris For example the ship counter is suited to a protracted war of attrition and is used to make a ground mine hard to sveep Ship counters could be used in anti-Polaris mines but very possibly would not be On 1he other hand delayed arming would probably be very attractive It is possible to lay down a defensive mine fieldin territorial waters announce its presence and defend it To transit such a mine field would be essentially impossible if the defender used some sonar pickups to detect stealthy activity At the present time there are no areas where such a 1 defensive mine field would much hamper Polaris operations Hovever if the political situation around the Mediterranean were to change this might no longer be true An extensive mine field such as this could be used to exclude all ships friend and foe alike To leave open lanes for the passage of friendly ships invites the submarine to sneak through by following How- ever it is possible to assemble mines which are specifically directed against submarines not only moored mines set below surface shipping but also mines which are set for specific submarine signatures are undoubtedly 1i i ' S'E'C 'RE-l l if RM-23ll 10-28-58 l 2l possible One conceivable combination vhich exploits the quietness of the submarine would be to require a magnetic signature a weak pressure signature and the absence of an acoustic signature Even more specificity would be obtained by requiring the signature of the nuclear submarine And the Russians might even be able to conwct a device which recognizes American nuclear submarines It is one thing to lay down an extensive mine field in territorial waters it is quite another to mine international waters In most areas the Russians would stand small chance of doing it without detection and probably other nations would resist with force Exceptions might be made for the Barents Sea where the Russians are strong and our surveillance is haphazard The Black Sea is a lot more risky but not necessarily critically so Sporadic sneak mining in open waters or even covert mining in NATO territorial waters' is much harder to detect It is not beyond a 11 reason that such methods might be used to attrite our submarine force in peacetime An occasional loss at sea even if known to be by mine would cause all sorts of diplomatic furor b t would be difficult to pin down An exploded mine is fairly anonymous particula rl y in waters which were mined during World War II It would be exhausting a nd fruitless to sweep extensive areas against sporadic mining the only real hope would be to catch them in the act and this is unlikely Remotely operated mines are quite feasible not only by cable to the beach or to a friendly boat but a lso by acoustic or low-frequency radio control It may seem a drastic approach but it is not beyond technical possibility for the Russians to lay numerous controlled nuclear mines in potential Polaris operating a reas these to be a tonated simultaneously with ilt HEu RM-231 l 10-28-58 122 an attack on the U S How effective any plausible level of such mining would is most uncertain but it must be borne in mind that the Polaris weapon system may be sensitive to modest levels of shock RM-2311 10-28-58 l29 - -· RM-23ll 10-28-58 130 J - Qj ' l f-J J-J V - ' 1 J c I ' ----- - s·Esm · 144 RM-2311 10-28-58 8 RM-2311 10-28-58 127 I i ro ro f f l '• l t· ' v l • · --sECR EJ ·t LA -1 ' RM-23ll 10-28-58 126 - -- BM-23ll 10-28-58 125 i r • • ·t '1 J ✓ I_ l I _ 'J i ' ' · V I - -- • L tt ' ' - RM-2311 10-28-58 123 Appendix D WEAPON EF CTIVENESS Figure l shows the number of weapons required'for the destruction of point targets as a function of hardness yield and CEP Figures 2 through 7 show the number of weapons required for various average levels of structara 1 collapse and fatalities against a target system ma de up of the 135 Soviet cities with populations of at least 100 000 These curves were generated from information available in RAND Research Memorandum RM-1671 which is a detailed analysis of the structure of eight Soviet cities and their vulnerability to a wide variety of attacks ties were associated with structural collapse of buildings Fatali- The buildings were assumed to be drag-sensitive which reduces the overpressure requirement for larger-yield weapons The effects of radioactive fallout or fire storm were not considered nor were civilian defense shelters although the population was protected by those measurf iavailable to an unhardened city There was no evacuation of the population The attack consisted of using weapons of the same size on the entire target system For those targets I requiring more than one weapon multiple a illl points and multiple weapons up to 13 were considered The force size represents the number of weapons that must be detonated on target No allowance bas been made for the effects of enemy attrition or disruption nor have launch and in flight reliabilities been accounted for In generating these graphs a particular veapon yield was chosen first The number of these weapons required for each of RM-l67l 1 s eight exemplar Hanunian N A Urban Blast Dama e 'J ™-1671 J uly 15 1957 Secret-Restrict ed Data i• S·EC Rli 1 l 7 7 1i1rir · u - and Delive Ac urac s·ECRlJ · iH 1 i d•lf li -' J h 1t _ V · n ' ff 0 _ - •··- M _ J r - ----· • ·-- - - - _ § Table 9 · I f l'I Q W SUMMARY OF WEAPON-EFFECTIVENESS FACTORS 01 r 0 Exemplar Cities Molotov Komsomolsk Saratov Tashkent Ufa-Chernikovsk Gorkiy Oroznyy Others Total Stalingrad Number of Similar Cities 3 3 4 578 1 066 3 176 525 538 147 ·- 8 11 12 1 320 4 131 3 717 4 079 330 113 731 778 901 109 6 13 44 35 135 Pop llation of Similar t- Ci lies t housands of Persons Tolal Largest Smallest 240 101 11 627 6 891 4 839 188 5 596 43 005 211 350 102 102 r Ru dlus of ' Similar Ci t ies miles Lo rgest Smallest 4 5 3 2 4 o 1 7 2 9 1 4 4 3 1 6 3 0 1 5 4 5 1 0 5 9 1 8 4 7 2 7 o B 0 9 Others are to be lumped together with either Tashkent or aroznyy whichever bas the smaller m unber of weapons required ___ 0 '- A ---· - -------- -- --- - - - - J - ' c · · tlil ' I RM-2311 10-28-58 l 31 cities vas then determined for the desired damage level Due to having dis- crete weapons the average damage level was often larger than the desired damage level This is particularly true f or the case of a large weapon against a small city in which one weapon does considerably more damage than desired The number of weapons for each exemplar city was then multiplied by the number of cities s illlilar to the exemplar The sum of these products repre- sents the force size required for the conditions chosen The accompanying Table 9 stmmia rizes the various factors pertinent to this method SECRET l--t- -5