if rm 1 13m a Mr343 1 a 8-2 - erfms'gf'w Antlw gu 511551 By g COPies Date 03-23-2011 - MDC 32317 TIT-LE FINAL REPORT ARMS CONTROL IMPLICATIONS OF STRATEGIC OFFENSIVE WEAPON SYSTEMS U VOLUME IV Technological Feasibility of Launch-On-Warning and Flyou't Under Attack U 96 PREPARED FOR The Arms Control and Disarmament Agency PREPARED BY I - - - - - - l 1 4 0 - W nAEROSPACE SYSTEMS ANALYSIS A MCDONNELL- DOUGLAS ASTRONAUTICS COMPANY if 5301 Bolsa Avenue A Huntington Beach Calif 92647 I illr ACDA MAILING ADDRESS g Post Office Box 3084-4 If Midway City California 92655 MCDONNELL DOUGLAS CORP 2'3 A I - GROUP 1 Ezciuded from automatic downgrading and declassificafion - T - rut- DOCUMENT CONTROL NO FINAL REPORT ARMS CONTROL IMPLICATIONS OF STRATEGIC OFFENSIVE WEAPON SYSTEMS DOUGLAS VOLUME IV Technological Feasibility of Launch-On-Warning and Flyout Under Attack IU JUNE 1971 MDC PREPARED FOR The US Arms Control and Disarmament Agency PREPARED BY ARMS CONTROL STUDY GROUP AEROSPACE SYSTEMS ANA LYSIS APPROVED BY 89% R E JOHNSON STUDY MANAGER ARMS CONTROL STUDIES AEROSPACE SYSTEMS ANALYSIS 1 APPROVED BY Zak N MANAGER AEROSPACE SYSTEMS ANALYSIS THE JUDGMENTS EXPRESSED IN THIS REPORT ARE THOSE OF MCDONNELL DOUGLAS CORPORATION AND DO NOT NECESSARILY REFLECT THE VIEWS OF THE UNITED STATES ARMS CONTROL AND DISARMAMENT AGENCY OR ANY OTHER ORGANIZATION OF THE UNITED STATES GOVERNMENT MCDONNELL DOUGLAS ASTRONAUTICS COMPANY FIESTFI ICTED DATA 5301 BOISE AVENUE Huntinglon BEBCN CA 9264 7 This document contains restricted data as defined in the AtomIc Energy Act of 1954 GROUP 1 its transmittal or the disclosure of its con- EXCLUDE FROM tents in any manner to an unauthorized AUTOMATIC DOWNGRADING person is prohibited WW AND DECLASSIFICATION Hw# 51551 DocId 32700119 11 This page Unclassified Voluiine i PREFACE This document IS Volume IV of a seven volume final together with two data books presents the results of Contract a study of the Arms Cont101 Implications of Strategic Offensive weapon Systems The data and analyses rep011ed in these volumes and data books used the results reperted previously for Contracts and and represent a significant extension in scope and depth of those results The primary emphasis in Contract was on analysis of sin vivability and penetration issues a1ising f1 om the inteiaction of stiategic arms limitations and the advancing technology of st1ategic weaponry In addition analysis of country offensive missile development capability was pe1f01 med To provide a consistent aeoessible and timely database for the analy ses performed the data books on U and Soviet strategic offensive weapon systems which were prepaied under Contiacts and AC 180 were updated and extended This study provided the U S Arms Control and Disarmament Agency ACDA with the following products A An updating of the data base for U S and Soviet offensive weapon systems 1 U S Strategic Offensive Weapon Systems Data Book U McDonnell Douglas Corpmation Report No MDC 32289 April 1971 2 USSR Strategic Offensive Weapon Systems Data Book U McDonnell Douglas Corporation Report No MDC 32288 Apri11971 B A final report comprised of seven volumes 1 Volume 1 Summary U 2 Volume II Strategic Missile CharacteristiCs and Related Arms Control Constraints U I This page Unclassified DocId 32700119 This page Unclassified Volume iV 3 Volume NCA Defense Related Issues U 4 Volume IV Technological Feasibility of Launch-On- Warning and Flyout Under Attack U 5 Volume V SSBN'Survivability U 6 - Volume VI Forward Based Aircraft In A Strategic Role U 7 Volume VII Impact of Technology Exchange On Country DevelOpment of Ballistic Missile Delivery Systems U This study was performed under the cognizance and direction of the ACDA Science and Technology Bureau and the advice and cooperation of the Project Officer E E Anschutz is gratefully acknowledged Other AC DA personnel whose assistance was invaluable to the study are J B Resnick Volume and C Henkin Volume VII This final report was prepared by the members 'of the Arms Control Studies Group at the McDonnell Douglas Astronautics Company MDAC This group consists of R E Johnson Study Manager T W Winn Deputy Study Manager I B Koriagin H Kumagai Additionally many of the engineers and scientists in the Development 3 Engineering and Advanced Systems and Technology organizations at MDAC contributed to the study This volume addresses the technological issues bearing on the feasi bility of alternatives to riding out a counterforce attack on the Minutes man Two possibilities are investigated- launching before a pindown attack can be initiated and flying out through a pindown attack The effects of a nuclear environment on Minuteman during boost are dis- cussed along with possible approaches to hardening the system This page Unclassi ed DocIdz32700119 Section Section Section 'Section Section Section Section Volume IV - CONTENTS PREFACE LIST OF FIGURES INTRODUCTION SUMMARY 2 1 Launch On Warning 2 2 Feasibility of Pindown 2 3 Flyout Against a Deficient Pindown Attack 2 4 Conclusions PREEMPTIVE SC ENARIOS 1 Alert Status 2 Potential Soviet Preemptive Capability 3 Preemptive Attack Strategies LAUNCH NING 4 1 Attack Flight Time Requirements 4 2 Warning Systems and Delay Times 4 3 U S Strategic Command and Control 4 4 Feasibility of Launch-On Warning FLYOUT UNDER AT TACK The Pindown Environment Minuteman Vulnerability Soviet Requirements to Guarantee Pindown Flyout Against a Deficient Pindown Attack Viability of Pindown me-ri-e U 5 OPTIONS REFERENCES DocId 32700119 Appendix A Appendix ase Volume IV - MINUTEMAN PROPULSION AND STRUCTURE VULNERABILITY A 1 Introduction and Summary A Vulnerability Evaluation A 2 1 Motor Case Wall Heating A Z 2 Motor Case Front Surface Spall A Z 3 Motor Case Back Surface Spall A 2 4 Case to Liner Bond Failure A Z 5 Line to Grain Bond Failure A 2 6 Structural Bandage to Nazzle A 2 7 Nozzle Throat Insert Damage A Z 8 Grain Damage - Up the-Nozzle Exposure A 2 9 Post Boost Propulsion System PBPS Vulnerability A Z 10 Summary A 3 References MINUTEMAN GUIDANCE AND CONTROL VULNERABILITY B 1 Nuclear Weapon Lethal Mechanisms B 2 Weapon Effects on Minuteman Components B Z 1 Prompt Ionizing Radiation B 2 2 Neutrons B 2 3 X Radiation 13 2 4 Electronlagnetic Pulse B 3 Boost Phase Survivability B 4 Glossary B 5 References INDEX 104 L Number 5 5 5 6 5 7 This page Unclassified Volume IV FIGURES Minuteman Pindown Requirements U Minuteman Saved by Flyout All Wings U Soviet ICBM rIirne of Flight Versus Range NRE U Time of- Flight Versus Range U Soviet SLBM Time of Flight to SAC Targets U National Command Warning to Response Cycle U Minuteman II Boost-Phase Vulnerability 1 Mt Weapon U Pindown Geometry Wing Weapon 1 cal err Z U Wing I Air Force Base U Pindown Geometry Wing Weapon 1 cal cm2 U Pindown Geometry Wing 1-Mt Weapon 5 cal urnZ U Minuteman Pindown Requirements U Minuteman Saved by Flyout During Attack Wing I U Minuteman Saved by Flyout All Wings U Altitude Dependence of the Free-Field Environment for a 4 th Weapon Temperature Rise for Various Case Thieknesses Steel This page Unclassified Page DocId 32700119 in This page Unclassified Volume IV - Number - Page Temperature Rise for Various Case Thicknesses - Titanium 71 A-4 Temperature Rise for Various case Thicknesses - Fiberglass 72 Peak Stresses in Steel - PUFF Data U '73 Peak Stresses in Titanium PUFF Data U 74 Peak Stresses in Fiberglass - PUFF Data U 75 A-8 Energy Deposition in PBPS Propellant Surface Under Steel and 2 54 cm Liner U 81 A-9 Energy Deposition in PBPS Propellant Surface Under Fiberglass and 2 54 cm Liner U 82 ilk-7 10 Energy Deposition in PBPS Prepellant Surface Under and 2 54 cm Liner U 83 A-ll Energy Deposition in Silica Phenolic MK-2600 U 85 Damage Threshold for Up Nozzle Exposure of Solid Propellant U 88 7 This page Unclassified DocId 32700119 Number 2-1 2 2 3-1 3-2 4 - -1 A-l 'A This page Uncfassified Volunie IV - TABLES Feasibility of Evading Pindown U Soviet Minimum Guaranteed Pindown Requirement U Characteristics of Soviet Systems Possessing Preemptive Strike Utility U Potential Soviet Counterforce Effectiveness Under Offensive System Deployment Moratorium U Early Warning System Performance U Feasibility of Evading Pindown U Soviet Minimum Guaranteed Pindown Requirement U Minuteman Motor Case Data U Motor Case Wall Heating and Spall U Case to Liner Bond U Grain to Liner Bond U Nozzle Structural Damage U PBPS Survivability and Hardening Summary U Ascent Phase Nuclear Environment U Weapon Effects on Minuteman by Component U Minuteman Vulnerability U This page Unclassified DocId 32700119 Page 100 tr Volume Section 1 INTRODUC TION Even though an agreement may emerge from SALT within the next year the survivability of the land based ICBM force remains one of the cru cial strategic issues Even if the agreement includes a moratorium on offensive deployment it is within the limits of technological feasibility for the Soviets to improve the accuracy of their to the point that they are a definite threat to Minuteman survivability Nothing short of rigorous enforceable control of qualitative improve ments in offensive systems can prevent Soviet achievement of counter force capability if they choose to exercise this option Such control is highly unlikely On the other hand it is quite possible that the ABM agreement will preclude defense of the Minuteman and it is almost cer tain that if a defense is allowed it will only be a token therefore other Options must be sought to preserve the land based force One way to improve Minuteman survivability would be for the U S to adopt some variation of launch-on-warning LOW LOW if adopted by the U 8 would make the survivability of Minuteman insensitive to qualitative improvements in the Soviet strategic missile force With the deployment of satellite based warning systems the U S has nearly 30 minutes warning of counterforce attack on the Minuteman by Soviet 1C If the Minuteman can be launched within that 30-minute inter val the accuracy of the Soviet will be unimportant because the Minuteman silos will be empty While LOW certainly represents a solution to the Minuteman surviva- bility problem it is not without drawbacks First there is the possible problem that the command and control machinery which is required to launch Minuteman may be incapable of reacting within 30 minutes-- particularly if the attack is a complete surprise If LOW is feasible two other major objections raised against a LOW doctrine are LOW increases the risk of nuclear war because the National Command Authority NCA must initiate its response on the basis of information from potentially fallible sensors and there may be strategies avail able to the attacker whereby he could deny a LOW capability even if the U S were willing to implement such a doctrine Pindown using the Soviet is the most likely strategy for this purpose 9 DocId 32700119 '1 14 3 Volume IV - This study examined the technological issues associated with the three objections cited above The feasibility of launching before the ICBM's could arrive was examined Options open to a potential attacker to defeat LOW were also examined these options ranged from attempting to mask his intent in order to delay U S response to use of depressed trajectory SLBM's in an all out pindown attack to keep the Minuteman bottled up until the can arrive A simple flyout strategy was developed which provides guaranteed survival for some portion of the Minuteman force against all but very large inventory pindown attacks Throughout the study an attempt was made to maintain the viewpoint of a Soviet planner Because deterrence is so much a product of per ceived rather than actual capability the credibility-of LOW or flyout capability to an outside observer is perhaps more important than their actual feasibility This report is organized as follows Section 2 contains a summary of the report and its conclusions Section 3 examines preemptive scena rios isolating those elements which bear on LOW feasibility Sections 4 and 5 examine the feasibility of LOW launch before pindown is possible and flyout under attack Section 6 discusses U S options of both sys tems' development and arms control p1 oposals which could eliminate the threat of a pindown attack Two appendiXes contain a discussion of Minuteman vulnerability to nuclear effects and ways to increase the hardness of the system Appendix A discusses the propulsion system motor case and structures while Appendix discusses the guidance 10 DocId 32700119 Volume IV - Section 2 SUMMARY n One of the principal objections to LOW as a strategy can be dismissed after an examination of reasonable preemptive scenarios There is no attack strategy which could be guaranteed to result in effective pindown and which conceivably could be construed as anything but a deliberate counterforce attack The inventory required for effective pindown is too large and the coordination of too many platforms SLBM and ICBM is necessary for a pindown attack to be regarded as either accidental or unauthorized The danger of a false alarm triggering a nuclear war is also exaggerated of a false alarm by any one of the warning systems is negligible the probability that two warning systems measuring entirely different phenomena would report correlated false alarms at the same time is infinitesimal More important the nature of a serious pre- emptive attack is such that time sensitive targets such as SAC bases command and control centers etc must be attacked in the first few minutes if the attack is to succeed Thus the evidence of the warning systems would be corroborated by nuclear bursts onor over the United States before the Minuteman could be released The remaining arguments against LOW are dealt with in more detail in the following subsections 2 LAUNCH -ON -WARNING The major problem associated with implementing a LOW doctrine other than the willingness of the NCA to actually employ such a policy-- is the possibility that the attacker may be able to pin the Minuteman down before the launch command can actually be eXecuted and the missiles get i away safely For'the purpose of this study LOW was assumed to be denied if the enemy can detonate an SLBM warhead over the Minuteman wing before the first Minuteman which can be launched is outside the lethal radius of the warhead There are physical limitations to the strategic warning and command systems as well as built-in safeguards to minimize the chance of an accidental launch together these factors result in a protracted interval between the first perception of an attack and the flyoui' to safety of the - DocIdz32700119 Volume IV - first missile launched The most important and least predictable delay is associated with the assembly of the NCA and the time it requires to assimilate the situation understand the options and determine a response This delay is obviously highly scenario dependent if the nation is in a state of strategic alert the NCA will be secure andmuch of the decision process will be speeded up On the other hand-rvif the attack is a surprise just assembling the NCA and determining who is in charge could consume hours Other significant delays in the com mand link are the four minutes required for formatting and transmitting the launch command from the National Military Command Center NMCC to the Launch Control Center -LCC and the 11 minutes needed for decoding and verifying the message and initiating the launch In addi-- tion the missile is extremely vulnerable to nuclear effects throughout powered flight another 175 seconds for Minuteman although after approximately 150 seconds of flight the missile is far enough downrange that bursts in the vicinity of the launch area are not likely to affect it Table 2-1 shows how the Minuteman response time compares with Soviet SLBM time of flight to the various Minuteman wings Four different cases which could arise over the next few years are considered This table assumes that no time is consumed by the NCA decision-making process Current U S and Soviet capabilities are shown in the first row of Table 2 1 This case assumes that the U S does not yet have a satellite-based early warning system over the SLBM launch areas and restricts the Soviet Union to nominal trajectories Even so the Minute man clearly cannot escapebefore the first Soviet missiles arrive 'The other three lines of Table 2 1 represent hypothetical situatiOns which could be possible in the time periods indicated By 1973 the U S will have a boost-phase warning capability in the SLBM launch regions This will effect considerable saving in time to launch Minuteman but the saw-- ing is not adequate to insure Minuteman- launch before the could arrive In addition the improvement could be offset by Soviet develop ment of a depressed trajectory threat It might also be possible by 1973 or thereafter for the U S to improve Minuteman launch-crew capability to meet the original standard of six minutes from receipt of command to execution If this could be done or if an equivalent length of time could be saved in some other way and the Soviets do not develop a depressed trajectory threat a launch-on warning capability would be marginal given the highly optimistic assumption that the NCA is ready to react instantaneously Once again however a depressed trajectory threat would be adequate to forestall such a capability This interval is determined by the slowest crew for fail safe and attack coordination reasons and by no means is a lower bound on the time required 12 DocId 32700119 9 I 61100LZE pIoou 51 Table 2-1 FEASIBILITY OF EVADING PINDOWN U Attack Starts at 0 A11 Units in Seconds Strategic Alert 11 SLBM Tune 0f Flight Earliest Possible Wings II Wings I Minuteman Time Period V VI 8 IV Launch Time Earliest Time to Safety 2 3 Current 73o - 850 600 1 100 1 275 2 1973 1976 586 746 456 933 1 160 1 - P 1973 1976 586 7425 456 860 F 1975 - 1980 913 1020 708 6'53 860 Depressed trajectory threat fFBoost phase warning system Improved launch crew facility - submarine standoff new SLBM required for range Volume 1V - The only way it appears possible to guarantee that Minuteman could fly out to safety WOuld be for the U S to enforce either through agreement or by ASW capability a Soviet submarine standoff from our shores at at least 500 miles This would put the north central Minuteman wings out of range of the Even if the Soviets deploy or some other longer range SLBM with depressed trajectory capability at this range LOW would still be possible although NCA reaction time would have to be very fast under two ininutes The discussion above does not rule out the possibility that LOW may appear credible to the Soviets A Soviet planner is unlikely to have detailed insight into U S command and control delays His assessment of U S response time is likely to be predicated principally on his experience with his own system it may be either smaller or greater than the actual delay in the U S system Consequently the discussions above do not necessarily indicate that a Soviet planner would be willing to discount a LOW threat especially in a strategic alert situation 2 2 FEASIBILITY OF PINDOWN If the Soviet Union were to attempt a preemptive attack against U S strategic forces within the next decade the mission of actually destroy ing the hardened Minuteman silos necessarily would fall to the SS-9's and SS-ll s To attain the accuracy required these ICBM systems would have to fly close to nominal ballistic trajectories and thus would require at least 3OIminutes to reach the Minuteman silos from their locations in the central Soviet Union On the other hand Soviet SLBM's on depressed trajectories can reach the Minuteman silos in 10 to 12 minutes Minuteman can be ready to launch 19 minutes given current warning and command delays after the attack begins with suitable adjustments in doctrine and systems and with boost phase warning this interval potentially could be reduced to 11 ininutes or less If the Soviets do not pin the Minuteman in their silos the entire force could be launched before the preemptive strike occurred If the Soviets elect to pin the Minuteman down it is by no means certain they can succeed unless they have a large inventory of to assign to the job The lethal mechanisms which are most effective in the pin down attack viz x-rays do not persist they are released and dissipated within microseconds after the bomb bursts Thus to insure pindown the attacks must detonate bursts at frequent intervals in order that any Minuteman attempting to flyout is within a lethal radius of at least one burst at some time during powered flight Pindown must start before the first Minuteman could be launched and continue until the first wave of ICBM's arrives l4 DocIdz32700119 - Volume IV - Factors in addition to the duration of the attack which determine the number of weapons required to insure pindown are geometry of the Minuteman wing 2 hardness of the Minuteman during powered flight and 3 yield of the attacking weapon -Wing geometry has a significant effect on pindown requirements The Optimum pindown strategy is to detonate warheads at approximately 25 nmi altitude about 25 nmi north of the Minuteman wing The number of bursts required is determined by RV lethal radius and the width of the threat tube The latter in turn is a functionof wing geometry and the angle subtended by potential targets in the Soviet Union in this study only targets in the western half of the Soviet Union were con- sidered The interval between successive bursts is determined-by the time required for a Minuteman to fly through the lethal volume generated by a single burst A wing which is wide from east to west such as Wing I requires more bursts to cover the threat tube than one which is narrow such as Wing VI However Wing V1 is long in the north south direction and therefore the bursts must be repeated more frequently because a missile launched from thesouthern most part of the wing can traverse the lethal volume generated by the burst in 40 seconds Wings II through have approximately the same overall geometric configuration and require identical pindown attacl s two bursts every 50 seconds Table 2 2 summarizes the requirements for all the wings if Minuteman hardness is cal cm2 and the SLBM warhead yield is 2 Mt The pindown requirement is extremely sensitive to the attacker s as sess ment of Minuteman hardness The number of RV's required varies with the square of the hardness level because a variation in hardness changes 'both the number required to cover the width of the threat tube and also the time required for Minuteman to fly through the lethal volume The sensitivity increases at higher hardness levels 4 to 5 cal crnz because the depth of the threat tube becomes large relative to the lethal radius of the warhead thus necessitating tandem bursts one above the other to insure that no Minuteman can escape The overall impact impact of hardness is shown in Figure 2-1 in terms of the number of RV's required per minute of pindown for both 1- and SLBM warheads It is of course impossible to state what the Soviet assessment of Minuteman vulnerability might be but is is reason able to guess that he would prefer to work with sure kill values rather than'sure-safe values For Minuteman the sure kill levels are 2 to 10 times the sure safe numbers 2 3 FLYOUT AGAINST A PINDOWN ATTACK The Soviet planner's total inventory requirements for a guaranteed pin- down attack can be estimated from Figure 2 1 If the planner is fairly 15 Dochdz32700119 'Volume IV Table 2 2 SOVIET MINIMUM GUARANTEED PINDOWN Inte rval Maximum Number of Between Pindown Number of d Wing Bursts Bursts Duration Required SLBM Yield 2 Mt Minuteman Vulnerability 1 cal cmz reckless and assesses Minuteman hardness at cal cmz and if his SLBM warheads have their estimated yield of 1 Mt 20 minutes of pin down will require 600 on-station within 100 miles of the U S coast Because it is practical to maintain no more than about two thirds of an SLBM force on patrol at any one time k the Soviet planner s requirement for a successful pindewn attack under these circumstances is 900 missiles and 56 submarines At his current SSBN production rate he could not mount a guaranteed pindown attack against the Minuteman for at least five years Although the Soviet SLBM three is inadequate to enforce pindown it may i be argued that they might try such an attack nonetheless relying on U S uncertainty as to the nature and magnitude of the attack to keep the Minutemen bottled up If they were to attempt such a strategy the U S has the option of flying out in such a way that the survival of at least some Minutemen is guaranteed This can be done very simply Minute- man launches are timed and sequenced in such a way that no pindown RV ActualSovietbaliistic missile submarine operations have not approached this figure N0rn1al l y less than one fourth of the Soviet SLBM fleet is at sea and these do not usually patrol within 200 n mi of the U S coast 17 sis-seer DocId 32700119 Volume indu 93MINUTEMAN BLHNIW 30 USEWHN If sJ inuteman Pindown Requimm nts U Figure 2-1 DocId 32700119 -- - - - - i - Shana-vJuan umIA VolUme IV - can possibly kill Inore than a fixed number This tactic is accomplished in the following way at each wing the duration of the pindown attack is divided by the total number of miSsiles to be launched this factor yields the interval between successive launches Launch sequence is uniformly random over the wing Consider for example Wing I assume 20 min utes of pindown a SLBM warhead and an assessed Minuteman hardness of cal cmz Under these conditions it takes Minuteman at least 50 seconds to transit the lethal volume generated by a single pin- down burst Because the Minutemen are launched 6 seconds apart 20 minutes divided by 200 missiles 9 missiles at most are potentially vulnerable to the burst of an incoming RV However because the launch sequence is distributed uniformly over the entire wing the likelihood is that no more than three of these will be within one lethal radius of a given burst The major result of the flyout tactic is that the number of surviving missiles is sensitive only to the number of attacking RV's The attacker can do nothing to increase the number of missiles killed by any given RV Figure'Z Z plots the number of Minutemen saved by flyout as a function of the SLBM inventory which the Soviets devote to pindown The second ary abscissa on the figure indicates the number of SSBN's the Soviets would require to have the associated pindown capability The scale on this axis incorporates the following assumptions concerning SSBN avail ability and utilization A No more than two-thirds of the force is on-station B SLBM availability-reliability is 80% C At least 50 time-sensitive targets will draw SLBM attack these would include SAC bases-and central command instal- lations Washington D C NORAD Headquarters etc Figure 2 2 illustrates the folly of a pindown attack with an inventory that is notadcquate to guarantee the results The importance of this figure and the flyout strategy as a whole is not that the U 8 would want to employ such an option rather it is that it is wholly credible that the U S could employ such an option Any nation planning a preemptive attack on the Minuteman must recognize this and accept the possibility that a preemptive strike against Minuteman may fail completely if not supported by an adequate pindown attack As a final point recall that the requirements shown in Figure 2-2 are minimums and assume a warhead and a Soviet planner banking on U S sure-safe levels as adequate for his kill This weighs the game heavily in favor of the attacker If instead 18 - secaET DocId 32700119 DIDOU 6 IIOOLZE 1 E I MINUTEMAN SAVED BY FLVOUT 800 700 600 500 400 300 200 100 NOTE DURATIONYIELD - 2MT STATION 67% FORCE RELIABILITY 0 3 I ALLOCATED TO NON MISSILE TGTS so VULNE RABI LITY 1 - -7 - - - 11200 300 400 soo 600'14 ff-I - 100 RELIABLE ALLOCATED TO Pmoown ifTOTAL SOVIET Y-CLASS SUBMARINES Figure 2-2 Minuteman Saved by Flyout Wings v s I u 3 Volume IV - a one were to use moderately conservative assumptions Soviet point of View the requirements for an adequate pindown attack become imprac- tically large For example if the Soviets assess Minuteman sure kill hardness at 5 cal cmZ which is not impossible or really even iniprob- able their pindown requirement is approximately 1 900 to insure that no more than 30% of the Minuteman force survives flyout Factoring in the availability and reliability of the generates a requirement for 3 600 RV's or 225 ballistic missile submarines Z 4 CONC LUSIONS In conclusion while the Soviets may have the capability to initiate pin down before the Minuteman can escape they will net have the capability to mount an effective pindown attack for several years Further rela tively modest improvements in Minuteman hardness levels to 5 cal cmz coupled with improvements in the Minuteman command and control sequence designed to reduce the reaction time of the system without compromising its fail safe provisions would render a pindown attack completely impractical There are two potential arms control agreements which could reduce the viability of a pindown attack significantly an upper bound on SLBM deployment and a submarine stand off limit An upper bound on SLBM deployment would ease the requirements for Minuteman hardening A submarine stand off agreement 500 nmi or more would eliminate the current Soviet SLBM as a pindown threat and would also provide the NCA with valuable and necessary decision time 20 DocIdz32700119 a SEEHHEL i Yolume IV - Section 3 PREEMPT IVE SC ENARIOS The credibility of a launch-on warning LOW policy to a potential attacker is Critically dependent on his assessment of the time required for the National Command Authority NCA to make the decision to respond This assessment in turn is likely to be a function of the scenario i e the events leading up to the attack and the nature of the attack itself whether it is a surprise attack or the end result of a period of growing international tension Three basic elements of preemptive nuclear exchange scenarios bear on the feasibility of LOW and the effectiveness of flyout under attack A The amount of pre attack alert B The physical characteristics of the attack weapons C The nature of the attack massive attack sneak attacks etc This section presents a discussion of the impact of alert status on the feasibility of LOW or flyout under attack 2 a brief description of the forces available to the Soviet Union for the counterforce and pindown missions together with an estimate of the potential effectiveness of those forces if the U S elects to ride out the attack and 3 a discussion of the attack options open to the Soviets'and their validity for preemptive attacks 3 '1 ALERT STATUS Literally thousands of scenarios have been formulated to investigate the likelihood of a nuclear exchange between the U S and USSR They range from the sudden massive surprise attack with no strategic warning often called a blue-sky attack to attacks which occur only after extended periods of extreme tension possibly coupled with some non nuclear clashes For many years U S strategic force procurement was based on maintaining an assured do struction capability in the event of a 21 DocId 32700119 - j div SECI IE I - - r Volume Blue Sky attack scenario featuring a sudden all-out attack on the U S retaliatory forces 5 At the other extreme is the graduated response scenario in which the initial nuclear blow is struck with a single weapon directed against a specific military target as a show of resolve The purpose of this section is not to investigate the credibility of the various scenarios but rather to investigate the impact of the scenario on the feasibility of launch-on warning and flyout under attack For this purpose only the alert level is crucial because that determines such key factors as Location and protection of key NCA personnel B Willingness of NCA to respond to apparent attack on the basis of warning information C The number of time sensitive targets which must be destroyed by the attacker The concentration of U S ASW systems on the CONUS defense mission Undoubtedly one of the major sources of a delay in initiating a response to an apparent nuclear attack would be the assembly of the NCA and the decision process it undergoes'in such an environment especially in the Blue-Sky scenario Theoretically the President is empowered to order a retaliatory strike pragmatically he would probably be unwilling to do so without consultation especially because it is unlikely that he could be fully conversant with the retaliatory options available Thus it is probable he would defer a decision until he had a full understanding of the situation It is probable that a great many more considerations were brought to bear but this is the scenario which was consistently used in Congress to justify strategic systems expenditures Ironically it is the same scenario which is given least credibility by most strategic They point to the high risk inherent in such an attack the disastrous consequences of even partial failure and ask what could possibly be gained by a nuclear strike that would be worth the risk To make nuclear exchanges even remotely credible these postulate nuclear war as arising from a state of extreme tension characterized by recrimination sabre rattling and even major armed conflict in Europe or the Far East Even then nuclear war is either a last resort after all other options have been exhausted or comes about as a result of accident or misinterpretation of some action aggravated by the tension 22 DocId 32700119 Volume IV - Another important potential source of delay is the passing of the com- mand authority if the President is killed The President's survival is far from assured Washington D C is vulnerable to attack by Soviet submarine launched missiles and the warning time received in such an attack could be negligible If the President is not already in a secure place i e unless there has been adequate strategic warn ing -he must be considered vulnerable to surprise attack a If the President should not survive or is not immediately available at the NCA the assumption of his prerogatives by his designated succes- sors is unlikely before his status is confirmed Also the same problem e bein among the missing may well exist with regard to the obvious successor Finally the NCA must have some time to assess the situa tion and decide on the appropriate response 'It is unlikely that the NCA could assemble review the situation and authorize a retaliatory strike within the 10 minutes or less required for an SLBM to reach the Minuteman silo locations Therefore for con sideration of launch on-warning feasibility we will restrict considera tion to those scenarios involving a degree of strategic warning If a'huclear exchange arises as the result of a crisis in U S Soviet relations and thus is preceded by a period of heightened tension most of the NCA associated delays would disappear When a crisis becomes sufficiently severe that the possibility of a nuclear exchange is raised the NCA can be made secure the Options for retaliation can be reviewed and a course of action can be determined Then if a strike actually occurs the response time depends only on the time required to assimi- late the strike news decide on the option and execute it It is con ceivable that these actions could be accomplished within the time of flight of Soviet to Minuteman fields Thus LOW is at least potentially feasible if the attack Occurs after a period of strategic warning Flyout under attack is not so clearly precluded by a surprise attack There are two reasons for this First the time of flight for the Soviet counterforce-capable systems exceeds 30 minutes Thus the NCA would have considerably longer to respond than it does in implementing LOW Second as soon as any enemy weapon detonates on or over U S soil many of the reservations concerning whether to retaliate vanish The United States maintains an alternate command post Looking Glass on continuous airborne alert It is not clear under what circumstances this command post assumes control of U S strategic retaliatory forces but it is almost certain that some delay is involved while the status of the NCA is dete rmined 23 DocId 32700119 Volume IV 5 especially because it can be shown Subsection 3 3 that there are clear-cut distinctions between an accidental 0r unauthorized attack and one which is intended to destroy U S retaliatory capability Thus - the total time consumed by the NCA decision process may be reduced significantly 3 2 POTENTIAL SOVIET PREEMPTIVE CAPABILITY If as appears possible a moratorium on offensive weapon system deployment emerges from SALT the limits on Soviet strategic force levels and capabilities over the next decade can be-predicted with some confidence Both the 88 9 and 58-11 appear likely to remain in the - Soviet inventory possib1y in upgraded configurations The older and should begin to pass from the scene the reduction in numbers of strategic nuclear delivery vehicles SNDV would be offset by a growing SLBM inventory and possibly more ss-9's and SS ll's The Soviet SLBM inventory should continue to be comprised largely of the although the Soviets are flight testing a more advanced missile the No submarine large enough to accommodate thisdmissile has been identified so its appearance as an operational system does not appear likely before 1974 Because the has considerably more capability than the that would enhance significantly the effectiveness of the Soviet SLBM force it is likely that this missile or some similar system will enter the Soviet inventory before the mid 1970 s References 1 and 2 Table 3-1 summarizes the major characteristics of current Soviet 4 systems which have potential utility in a preemptive strike The poten- tial results of a strenuous qualitative upgrade effort are also shown References and 3 From the characteristics of the force shown in Table 3-1 it can be seen that SLBM's by themselves are not capable of the destruction of Minute man silos The combination of yield and accuracy is clearly inadequate This mission must be performed by the Soviet land based forces and The re are indications that SALT will produce an agreement between the U S and the Soviet Union to insure that accidental launch informa- tion is communicated immediately In the event of an accident it is in the best interest of the offending nation to honor such an agreement especially during a crisis There is no guarantee of course that a nation could not attempt to gain time by claiming that a deliberate attack was an accident The numerical differences however between the largest conceivable accident and the smallest feasible prelude to a preemptive attack are so marked that it is doubtful that a lie could be made credible in this situation 24 DocId 32700119 sw ixr a Volume IV - Table 3 - CHARACTERISTICS OF SOVIET SYSTEMS POSSESSING PREEMPTIVE STRIKE UTILITY U Payload Configuration No of Warheads Range CEP Force Year System Number Yield Mt nmi nmi Reliability 197158 9 306 1 18 6 500 0 5' 0 75 55 11 970 1 1 5 500 01 8 0 75 I a 320' 1 300 0 5 1 37 0 65 1976 53-9 306 3 5 5 400 0 5 0 9 or 6 2 0 25 58-11 970 1 l 5 5 500 0 25 0 9 1 - 1 300 0384 1 2 3 000 0 4 - 0 6 0 8 Twelve boats were operational by May 1970 construction rate was 8 boats year There are 16 missiles per boat - Maximun1 yield consistent with estimated RV weight 1 500 lb Current estimate Large-uncertainty arises from submarine navigation estimates and azimuth error uncertainty 3k 5 Assumes the Soviets begin to build a submarine compatible with the SS-NX-8 in 1972 and build to a construction rate of8boats year from 1974 through 1976 also assumes that boat con struction halts with completion of those boats currently under construction Soviets remain within SNDV limit by removing bombers and 85 7 and 88 8 missiles as submarines are deployed even these require extensive qualitative improvement The Soviet ICBM forces however require at least 30 minutes of flight time to reach the northernmost Minuteman fields Figure 3-1 while their SLBM's can reach the same areas in more than 12 minutes If the Soviet attempt a pindown attack it is clearly a mission for the SLBM forces The time of flight of the Soviet SLBM's could be dinnin ished if the nuissiles were flown on depressed trajectories Figure 3-2 25 DocId 32700119 9919 DIDOG GIIOOLZE h 2 200 - I MINIMUM RANGE TO MINUTEMAN - FROM $39 LAUNCH POINTS a I A a - 1000 3 I MINIMUM ENERGY A I a 1 300 TRAJECTORI - I II - LgDEPRESSED 7 - x' 1 400 TRAJECTOIRY '1 3724 1 3 3 000 4 000 5 000 5 000 I RANGE INMII Figure- 3-1 Soviet ICE-M Time of FiigItvs Range NEE U 199tg #mn 1 kph 3 igsrc TIME OF 2 3-2 1 000 500 400 00 800 200 Time of 831mm MINIMUM TRAJECTORY Volume lV - The Soviets have not demonstrated a depressed trajectory capability 3 with their 88 6 e they have not done the flight testing required Also estimated range of the 58 6 on a depressed trajectory is mar ginal to cover the n01th cent1al region although it could probably cove1 most of the other regions The 8 should have adequate perform ance to reach any point in the U S on a depressed trajectory when it is deployed circa 1973-to 1974 References 2 and 4 Table 3 2 shows the potential counterforce effectiveness of the current and 1976 Soviet threats if the United States elects or is forced to 'ride out a counterforce attack Note that there is no appreciable counte1 force threat at this time but if the Soviets were to aggressively pursue MIRV for the SS 9 and accuracy 1mprovement for the SS- 11 by 1976 85% of the Minuteman silos could be destroyed by a successful counterfmce strike Even hardening the Minuteman silos in this case to approximately 1 000 psi would not be adequate to meet the criteria of 300 survivable Minute- man vehicles calculations based on data in References 5 and 6 Soviet as well as their older s were not used to attack the Minuteman silos in this evaluationf-first because they are not re quiied second because they possess only limited capability and third because there a1e missions to which the at least are better suited viz destruction of relatively soft time- sensitive taigets and pindown of the Minuteman 3 3 PREEMPTIVE ATTACKISTRATEGIES The natural reluctance of the NCA to adopt a LOW policy is enhanced by concern that an accidental or unauthorized attack would trigger a mas sive retaliatory strike which in turn would cause a retaliatory attack on the United States To avoid such an exchange it has been suggested that a threshold attack size be adopted Then such a threshold must be exceeded before a retaliatory attack would be launched Critics of the threshold concept argue that an astute opponent could disguise the early stages of an attack- staying below the th resholduwhile sending in enough missiles to pin down Minuteman so that LOW is not possible This subsection examines the potential viability of disguised attacks as a means for denying LOW capability The requirement for and potential effectiveness of a disguised attack depends to a great extent on the alert status If there has been no period of strategic warning attacking with less than full force only serves to give those systems not attacked in the first wave a measure of warning In particular the national command centers should be attacked as early as possible Further any SAC bomber base not attacked immediately will be able to launch bombers until it runs out of planes or is destroyed Thus at least 50 targets must be as saulted in the first few minutes of 28 D0cId 32700119 I 62 Table 3-2 i o POTENTIAL SOVIET COUNTERFORCE EFFECTIVENESS UNDER OFFENSIVE SYSTEM DEPLOYMENT MORATORIUM U 15 Force Level 306 58 9 970 85 11 Configuration N0 of Both Systems and YieldOptimized Attack Year 1971 1976 1971 1976 1971 1976 CEP nmi1 0 11 0 77 No of Silos 2 Destroyed 3 3695 8 1 000 Total f 243 535 96 672 315 849 865Silos' Destroyed 1 000 Total 205 372 52 5 59 24 - 0 9 reliability 11Without with reprogramming for reliability Volume JV the engagement if the bombers are to be destroyed 0n the ground Because the bomber bases must be attacked from both the Atlantic and the Pacific the likelihood of such an attack being construed as either unauthorized or accidental is negligible If there has been a period of strategic alert some of these arguments are weakened In such a situation the opponent has no chance to destroy much of the bomber force because it will be on airborne alert Also the NCA undoubtedly will be secure Thus a disguised attack during a period of strategic alert could be restricted to Minuteman fields only without seriously affecting the outcome of the attack However the credibility of a disguised attack even against the Minute- man is open to question The lethal radius of a single weapon except an 58-9 is not large enough to pin down an entire Minuteman wing even briefly thus any attempt to pin down the Minuteman will require multi ple bursts on each wing It is shown in Section 5 that 13 two-megaton warheads are required just to cover the flyout corridors from the Minuteman wings for an instant Further the aimpoints of these bursts andthe coordination of the launches more than one submarine would be required will unambiguously define the attack as the initiation of a pindown attempt If the attack is a pindown attempt successive waves must follow within one to two ininutes otherwise pindown is not assured With a boost-phase detection system the second wave would be detected about a minute after launch less than three minutes after the first wave was launched and approximately 8 if SLBM to 25 if minutes before impact Also if pindown duration is to be a reasonable length the ICBM attack must be launched as soon as the pindown attack is launched Thus the U S warning system would see attacks from several locations from both ICBM's and almost immediately or the attack will be ineffectual Thus the nature of any pindown attack attempted must be clear long before burst of the first warhead A second indicator of the nature of the strike can come from the weapons employed -IC BM SLBM or both The probability that both and SLBM's would be involved in an accidental or unauthorized strike is miniscule On the other hand a preemptive strike which involved SLBM's only or ICBM's only would be equally unlikely If SLBM's are to be used to pin down the Minuteman any delay in launching the silo- busting prolongs the pindOwn duration thus increasing demands on the SLBM inventory If no pindown is attempted the Minuteman can be flown out any time If the first wave of the attack is small enough to be considered an accidental or unauthorized launch and not immediately followed by a second wave the U S can afford to ride it out and deter mine the proper reciprocal action If the first wave is an attempt at pin- down the succeeding attack must follow immediately hence the U S will once again have ample warning 3U 7 t'r Volume-IV - In summary it would appear that the most conservative assessment of Soviet capability to deny launch-on warning to the U S is to assume an all out attack using ciirected against SAC bases and comn ia d centers and for Minuteman pindown Assessments of LOW feasibility in this report will focus on this attack 31 DocIdz32700119 - -1 4 H PM 7 4 Volume IV - Section 4 For the purpose of discussion a convenient if artificial distinction is made in this report between launch-on-warning LOW and flyout during attack In this context LOW refers to the capability to launch at least some portion of the ICBM force before a pindown attack could begin flyout during attack refers to a launch doctrine that calls for launching Minuteman after some SLBM have burst but before the brunt of the ICBM attack arrives this doctrine involves accepting some damage from the pindown environment while exploiting windows in the pindown coverage This section discusses the issues bearing on the technical feasibility of LOW There are feur critical time intervals bearing on the feasibility of LOW A The time required for the attacking missiles to reach the Minuteman installations B The time delay between launch of the attack and warning of the attack the warning arrives at the National Military Command Center C The time required by the NCA to assimilate the warning and decide to launch the Minuteman force D The time required to code tra-nsrnit decode verify and execute the launch command and for the missiles to fly out a safe distance This section discusses each of the intervals and the doctrine and system limitations which result in the delays Then several preemptive attack scenarios are examined to determine the feasibility of LOW both now and in the foreseeable future 4 ATTACK FLIGHT REQUIREMENTS To some degree LOW is a misnomer because undoubtely there will be bursts on coastal time-sensitive targets long' before the Minuteman can get away In particular the enemy is certain to attempt to disrupt the NCA by destroying Washington D C This can be accomplished 32 a DocId 32700119 ands e- Volume IV - with little or no warning and would tend to confuse the command and control process Thus the decision to launch Minuteman may be m_ade after physical damage has been sustained to the U S from nuclear bursts However these issues bear on policy not on physical limita- tions of the system The point made here is that the warning on which the decision to launch is based Will probably include actual bursts on or over U S territory A preemptive planner can be eXpected to put a premium on a number of time-sensitive targets in the U S These include the NCA the alternate command posts NORAD headquarters and of course all SAC bases with bombers and tankers The number of SAC bases fluctuates In Reference 4 55 bases were identified and this number is used in this report The Air Force may reduce this number for econon iic'reasons however the number could increase drastically during a strategic alert rl he 55 SAC targets identified in Reference 4 are assigned in Figure 4-1 to regions based on the probable direction from which an SLBM attack would emanate Also shown on the map are the six Minuteman wings and the three Titan deployment'regions The three arcs on the map represent approximately equal distances from possible Soviet SLBM launch points in the Atlantic and Pacific Oceans the Gulf of Mexico and Hudson Bay The targets in the north central regions are about equally distant fron'i all three launch areas and from Hudson Bay The numbers in each region indicate the time of flight for nominal and depressed trajectory SLBM flights from the corresponding launch region Note that the maximum time required for an attacker to begin a pindown attack is about 14 minutes and that length of time applies only at the northernmost wings Pindown at Whiteman Air Force Base could begin as early as 8 minutes after launch 4 2 U S WARNING SYSTEMS AND DELAY TIMES The U S 'has three operational strategic early-warning systems and a fourth system in the early stages of deployment When the fourth sys- tem is fully operational the U S will have redundant coverage of missiles launched in the Soviet Union or in the Atlantic or Pacific Oceans north of the Equator commencing less than a minute after the missile is launched Performance data on these systems is summarized in Table 4 1 The four systems are A The Ballistic Missile Earlquarning System BMEWS a string of radars located in England Greenland and Alaska Actually pindown bursts will take place at fairly high altitudes this time of flight shown is from launch to a reentry altitude of 25 nmi 33 DocId 32700119 P1000 611100 LEE 3 I a h 1% GREAT FALLS SAC TARGETS it k TU cso 2 NOMINAL TRAJECTORY DEPRESSED TRAJECTORY FLIGHT TIME IN SECONDS Figure 4-1 GRAND FORKS N 730 8 50 RAPID D 580 - 740 CITY 48AC TARGETS CHEYENNE 4 WHITEMAN wz CH ITA 340-620 D 230-460 1OSAC TARGETS Soviet SLBM Time of Flight to SAC Targets tUSAC TARGETS Saris vow Al wnm J - 0- 9 6 Table 4 l EARLY WARNING SYSTEM PERFORMANCE U Time of Time of NMCC Detection and NORAD Probability Probability False Secs After Alert Secs of Detection of Detection Alarm System Launch After Launch Single Launch Mass Launch Rate BNIEVVSyears 440L- OTHF 1oo 400 1 0 1 per 6 months 4745 SLBM Net 150 200 2 3 0 5 o 96 '2 Boost-Phase 4 Detection Satellite nmi trajectory Five minutes of data processing required to determine detection can over y most of the 474N radar net in attacks on coastal targets 4 Not fully operational 9wn OA o 3 a - Volume IV AcoA smss B _The anti SLBM warning system called netting of converted SAGE air defense radars and the FPS-85 radar at Eglin Air Force Base in Florida designed to detect launched ballistic and cruise missiles C The forward-scatter over the horizon radar system designated receivers spread from Great Britain - to the Mediterranean and transmitters in the Western Pacific D Boost phase tracking system- satellite-based warning system which will cover both the interior of the Soviet Union and feasible SLBM launch areas when fully ope rational The BMEWS system is the oldest of the U S strategic warning systems Construction on this system of northward-looking radars began in 1958 and the system was completed in 1966 BMEWS would provide warning information to NORAD headquarters of a Soviet ICBM attack on the United States between 12 and 15 minutes after launch of the attack A multiple detection requirement insures that the false alarm rate is extremely low -estimated to be no more than one in seven years There have been no false alarms since BMEWS has become fully operational Probability of detection of a single ICBM by BMEWS is O 99 detection of anattack by more than one missile is assured Reference 5 The 4741 1 SLBM warning system was developed as an interim system to provide some warning against submarine -launched threats Most of the radars in the system are modified SAGE-system radars with extremely limited range against ballistic missiles As a result the newest Soviet SLBM the can over-fly most of the 474N system Against systems which are launched in the radars field of view warning would reach NORAD about 200 seconds after launch Probability of detection of a single launch is no better than 0 5 even when the missile is launched in an area that is covered by the system Detection of large attacks five or more missiles however is virtually certain Reference 5 The 44OL forward-scatter 0TH system reached IOC in 1968 but full operational capability was not achieved for an additional two years and work is continuing on improving the system s data pr0cessing capa bility The 440L system detects a missile as it penetrates the iono- - sphere typically within 100 seconds after launch but warning may not reach NORAD until up to five minutes later because of the data _processing required to verify detection The current 44OL systems trajectories into coastal targets only could not overfly 474N on a trajectory to any of the Minuteman wings 36 DocId 32700119 ii 11 Volume IV - cover launches in the Soviet Union OTH detection of launches involving more than one missile is virtually assured Ref 5 The three operational early warning systems described above leave serious gaps which could be exploited by an attacker Most serious of these is the lack of adequate SLBM warning It is quite conceivable that an SLBM attack could arrive at many U 8 targets with no warning whatsoever Particularly vulnerable are targets near the sea coasts the National Command Authority in Washington D C and about 70% of the U S population To remedy the SLBM problem and to provide more thorough and rapid coverage of the Soviet Union the U S is deploying a satellite-based boost-phase detection system When operational this system will provide warning to NORAD and to the NMCC of missile launches ICBM or SLBM within 1-1 2 to 2 minutes after launch The false-alarm rate is expected to be very low and detection of multiple launches is certain This system should be fully ope-rational by 1973 at the latest Ref 4 When the boost-phase detection system becomes operational the U S will have redundant coverage of the potential IC BM and SLBM launch points More important the systems and the phenomena observed by each system are independent of one another thus the likelihood of a false alarm registering on more than one system is virtually zero Also the likelihood of simultaneous failure of two systems is- equally remote rI'hus the U S will be assured of 1eliable warning of a Soviet attack no late1 than six minutes after launch and will have a high proba- bility of warning within two minutes of launch More important the Soviet planner must assume all warning systems are functioning there- fore he will not be able to count on masking his intent for more than one to two minutes In summary currently many c1itical targets and much of the population of the United States are subject to attack without warning Much of this vulnerability will be eliminated within the near future and warning will be received with high probability within two minutes of launch For the most part the systems which comprise the U S early -warning capability have low false-alarm rates and high reliability when con- sidered independently Taken altogether the early warning systems should insure that no launch could ever occur as the result of a false alarm if a launch on warning policy were implemented 4 3 U S STRATEGIC COMMAND AND CONTROL The t11i1d area to be examined to deteimine U S LOW capability is the opeiation of the NCA in reaching a launch decision and the execution of the launch command li iguz 4- is an idealized representation of the 522 51 DocId 32700119 1 P1000 6 IIOOLZE llBOMBER TAKEOFF WHOMBERS - LAU NC SENSOR 30 cm i's OF THE VARIOUS fl-Fm _r MISSILE FORCES - - 11FLEET COM- j MUNICATIONS Figure 4-2 National C mmand-Warning to Response Cycle U 1 u - eeL-ismaov- Al I 3 Volyrne IV U S strategic system warning-to-response conemand linkage showing the approximate time required to complete each link The upper line in Figure 4-2 shows the low of information leading to the SAC bomb'er force Because bombers are recallable NCA approval is not required prior to bomber takeoff The lower line in Figure 4 2 shows the prin cipal elements of the chain of command leading to Minutemanelaunch In the missile-command loop major uncertainty in the time required to complete the chain arises from the impossibility of predicting the reaction time of the NCA It is not really even possible to assign upper and lower bounds to this interval Even if the NCA is assembled and a response plan is already selected some time would be required to assimilate the nature of the attack On the other hand if the attack is a complete surprise and Washington D C is attacked early in the exchange just assembling the NCA or what is left of it may consume hours Because any assessment of this time interval necessarily must be extremely scenario dependent this study adopted the approach of determining how much time could be allotted to this process given the probable attack parameters and the known time delays Once the launch decision has been made at the NCA level there are still three significant delays before the missiles can be considered safe 5 The most important and the most surprising of the delays is the 11 minutes required by the launch control crew to receive decode authenticate and execute the launch command This time delay is not a minimum or even the average of all launch crews but rather it is an interval which has been established by Air Force doctrine to insure that no crew attempts to launch before all crews have completed their pre- launch functions There are two reasons why this interval is determined by the slowest crew The first results from a fail safe mechanism built into the Minuteman control Within each squadron 50 missiles and 5 launch control centers the are interconnected so that any can cancel a launch command issued by any other LCC Thus if even one crew in a squadron has not completed processing of the launch command it can and must cancel any other crew s command The second reason results from the requirement for a common time ref erence for all the missiles This common reference is required in In this case third stage cutoff is used as the time at which the missile is safe Minuteman actually remains vulnerable beyond this time because its guidance and post boost propulsion system remain active however it is more than 60 nmi downrangc from the launch point and at 110 nmi altitude It will be shown in Section 5 that extending a pin down attack to cover the region of post-boost propulsion system operations is inapractical 39' DocId 32700119 i seems Volume IV - order that the coordination built into the missile targeting can be accomplished this in turn is required to avoid fratricide at multiply- targeted aimpoints and to insure proper sequencing of which are attacking defense units etc It is understood that at one time this interval was fixed at six minutes but some crews were incapable of meeting this standard The 11 minute delay in the launch con-t-rol cen- ter together with the four minutes required to process code and trans- mit the launch command mean that 15 minutes are required to get Minuteman out of their holes after the decision to launch is made 4 4 FEASIBILITY OF Table 4-2 shows how the Minuteman response time compares with Soviet SLBM time of flight to the various Minuteman wings Four dif ferent cases which could arise over the next few years are considered This table assumes that no time is consumed by the NCA'decision pro cess Current U S and Soviet capabilities are shown in the first row of Table 4-2 This case assumes that the U S does not yet have a satellite based early-warning system over the SLBM launch areas and restricts the Soviet Union to nominal trajectories Even so the Minuteman clearly cannot escape before the first Soviet missiles arrive The other' three lines of Table 4 2 represent hypothetical situations which could be possible in the time periods indicated By 1973 the U S will have a boost-phase warning capability in the SLBM launch regions This will effect considerable saving in time to launch Minute man but the saving is not adequate to inSLIre Minuteman launch before the SLBM could arrive In addition the improvement could be offset by Soviet development of a depressed -trajectory threat It might also be possible by 1973 or thereafter for the U S to improve Minuteman capability to meet the original standard of six minutes from receipt of command to execution If this could be done or if an equiva lent length of time could be saved in some other way and the Soviets do not develop a depressed trajectory threat a launch on warning capa bility would be marginal given the highly optimistic assumption that the NCA is ready to react instantaneously Once again however a depressed-trajectory threat would beadequate to remove such a capa- bility The only way it appears possible to guarantee that Minuteman could fly out to safety would be for the U S to enforce either through agree ment or by capability a Soviet submarine standoff from our shores of at least 500 miles This would put the north central Minuteman wings out of range of the on a depressed trajectory If the Soviets deploy the its depressed trajectory capability would not be 40 SEQ-REJ- DocId 32700119 tplnou 6 IIDOLZE H7 FEASIBILITY OF EVADING PINDOWN U Attack Starts at 0 All Units in Seconds Table 4 2 Strategic Ale rt SLBM Time of Flight Earliest Possible Wings II Wings I 'Minuteman Time Period V VI 8 IV Launch Time Earliest Time to Safety Curent 730 - 850 600 1 100 l 275 1973 1976 58E 74E 45E 9EE 1 160 1973 1976 ESE - 74E 45E 860 1975 - 1980 - 70E 685 860 EzDepressed trajectory threat 5 d 4 4 - 1 T'E Boost phase warning system I WImproved launch crew facility WESubmarine standoff 500 nmi awnlon - lie Volume - adequate to threaten the Minuteman's LOW capability Such a standoff would provide the NCA with some time albeit only two minutes to make a decision Because the NCA cannot react instantaneously it appears that getting Minuteman out of the ground before a pindown attack could be initiated is not possible as long as the Minuteman comlnand and control structure remains in its current form Detailed information about the Minuteman command and control structure was not available to this study the re fore it is not possible to make specific recommendations abOut how this system might be improved or indeed even to speculate how great that improvement could be Instead this study will investigate in Sec tion 5 the possibility of flying Minuteman out of the holes even though an attack has begun Note that a Soviet planner is unlikely to have detailed insight into U S command and control delays His assessment of U S response time is likely to be predicated principally on his experience with his own system it may be either smaller or greater than the actual delay in the U S system Consequently the above discussions do not necessarily indicate that a Soviet planner would be willing to discount a LOW threat especially in a strategic alert situation 42 Ducldz32700119 v 7 w 1 Volume Iv Section 5 FLYOUT UNDER ATTACK From the Soviet planner s point of View it is unlikely to be sufficient to merely have the capability to initiate a pindown attack before the Minutemen are out of their silos he must also have sufficient missile inventory and the ability to coordinate the use of that inventory to insure that the Minutemen remain bottled up long enough for his to arrive In this section the inventory required to guarantee that the Minutemen are pinned down is calculated as a function of the hardness level of the Minuteman and the yield of the Soviet warheads Then the risk associated with flying out through a pindown attack which is deficient in inventory is examined to determine at what Soviet SLBM inventory levels flyout and rideout become equally attractive alterna- tives from the viewpoint of equal numbers of survivors 5 1 THE ENVIRONMENT The ideal pindown technique would be to create such a severe environ ment over the ICBM launch facilities that any missile attempting to fly out would be destroyed At the same time the nuclear environment must permit the incoming silo killing to penetrate to their targets with out risk Such an environment appears feasible because missiles nor- mally are far more vulnerable during boost to most of the lethal effects of a nuclear burst than are their reentering RV's The major problem with maintaining a lethal environment over the launch areas is the lack of persistance of most lethal effects from' a nuclear burst As Figure 5 1 shows many of the lethal effects from a nuclear burst extend over large areas but their persistence is measured in small fractions of a'second only dust provides a long duration hostile environ ment Dust is hardly a satisfactory pindown agent--the lethal radius is rela- tively small and it is the one mechanism that is more dangerous to an incoming RV than it is to a missile flying out The reason for the latter is the velocity difference between the two objects during their transit through the dust cloud the missile is accelerating from rest and the RV is near its maximum speed Because damage from dust collision varies with the kinetic energy of the object and thus increases with the square of the velocity the environment is 16 to 30 times more lethal 43 Decld 32700119 1' It - 5 12' Figure 5-1 Minuteman ll Boost Phase Vuinerability 1 MT Weapon U 414 3 - 42 USC 2162 a - RD DO I DocId 32700119 'E anasr Volume to the RV than to the ascending missile Further the attacker has no way of determining when the environment has cleared sufficiently to allow his to penetrate On the other hand the nation under attack has at least potentially the means to sample the environment and the dust will permit flyout long before any incoming RV would have a chance to penetrate An alternative to Creating a lasting lethal environment is to renew it at frequent intervals so that any missile trying to fly out will be within one lethal radius of a burst at some time during boost To minimize the number of required it is desirable to work in the altitude regime where the lethality of the warhead is' most severe From Figure 5 1 we can see that this means detonation at altitudes of 25 nmi or more and reliance on xhrays as the principal killmechanism 5 MINUTEMAN VULNERABILITY The-lethality contour shown in Figure 5 1 is Or an X-ray fluence of lcal cmz This is the assessed sure-safe hardness of the Minuteman system Minuteman II is actually assessed to be somewhat more vulnerable about 0 75Vcal cm2 From the standpoint of this study the actual sure safe hardness of Minuteman is less important than the value the Soviet planner -might assign to the hardness Because Minuteman vulnerability is most Critical in the area of electronics Soviet intelligence about this number is not likely to be very good Further the difference between the sure safe number quoted above and the sure kill that a preemptive planner is likely to require is considerable Sure kill levels may be from 2 to 10 times as high as the sure safe number The lethal mechanisms created by a nuclear burst in and out of the atmosphere and their effect on Minute- man are discussed in some detail in Appendixes A and B Because it would be virtually impossible to determine a Soviet planner's assessment of Minuteman hardness this study has treated the pindown problem parametrically and has examined Soviet pindown requirements for Minuteman vulnerabilities from 1 to 10 cal cmz An example has been selected to illustrate the method In this example the Soviet SLBM RV yield is assumed to be 2 Mt and the Minuteman vulnerability is set at cal cmz The reader should recall however that this is merely an example and in some sense it represents the lower bound on Soviet requirements rather than an expected value which undoubtedly would be much higher - 5 3 SOVIET REQUIREMENTS TO GUARANTEE PINDOWN It is has been argued that the precise number of weapons required to guarantee the pindown of the Minuteman is really unimportant because if any weapons were detonated over the Minuteman fields the 45 assasse DocId 32700119 sesser Volume 1V - is uncertainty of Minuteman survival through boost would be sufficient to keep Minuteman missiles in their silos This argument ignores the likelihood that a preemptive attack would not be attempted if the attaC ker were not confident of his ability to destroy most of the Minuteman silos It also ignores a viable Minuteman flyout strategvu one which can guarw antee some level of Minuteman survivability in the face of a deficient pindown attack This strategy will be described in Subsection 5 4 first however the requirements to guarantee that Minuteman is pinned- down will be calculated Figure 5-2 illustrates both the pindown problem and the manner in which the pindown requirements were ascertained The bottom part of Fig- ure 5 2 represents the region covered by Wing I of the Minuteman force the actual deployment is shown in Figure The top part of the fig ure shows side views of Minuteman trajectories with time marks indiw cated The trajectories shown coincide with launch points located at the extreme northern and southern boundaries of Wing I The pindown problem maybe stated in the fol-lowing manner the attacker assumes that his opponent knows the precise nature of his attack and can exploit any weakness for this reason he must deny any launch window to the pinned-down force Therefore he must insure that any missile fly ing out will be within a lethal radius of one of his weapons at some point during the boost phase Notice that it is not sufficient or even desirable to detonate weapons over the wing its elf pindown bursts should be down- range of the wing in the threat tube subtended by the Soviet target struc- ture The USSR subtends a rather large angle from U S Minuteman fields For the purpose of this study it was assumed that the Soviet planner would consider it adequate to pin down Minuteman aimed at the most valuable part of the Soviet Union and would accept some damage in the eastern regions Consequently the angle shown in Figure 5 2 covers Only that part of the Soviet Union west of 750 E Longitude The guaranteed pindown solution was deteimined for Wing I geometri callv from Figure 5- 2 The solution is bounded by two considerations the location of the pindown bursts must be far enough downrange from the launch emplacements to insure that missiles from the northern- most launch facilities do not escape under the lethal region but at the same time the burst points must be as close to the deployment area as possible to minimize the width of the threat tube Also it is desirable to keep the burst close to the wing in order to operate where the ascending mis side is still traveling fairlyr slowly From the top part of Figure 5 2 we can see that the time required for Minuteman to traverse the lethal volume generated by a burst is affected strongly by the downrange dis tance of the burst from the launch point Consequently to maximize the interval between bursts the burst points must be as close to the wing as possible 46 6% DocI_d 32700119 Vofume IVI 2 15 i-ii fFLIGHT v- LETHALIVQLUM Hi'31lot DOWNBANGE - ANGLE SUBTENDED av EUROPEAN RUSSIA 7 1- II I 0'RSTS 150 SOSEC INTERVAL 4x 1 NORTH 200 DOWNRANGE NMU DocId 32700119 19919 P1006 SIIOOLZE atLEGEND - - a eel-Lskv'oov' I m1 xm 3 - nhnuwv he 7 y Figure 5-3 WingLMaimstrom AFBIU S Volurine - The locations shown in the bottom part of Figure 5 2 are nearly optimal for Wing I Note that Minuteman requires at least 50 seconds to' traverse the lethal volume generated by these burst points regardless of the leca 'tion in the wing from which the Minuteman is launched This determines the frequency with which the pindown burst must be repeated In this case the three bursts required to comer the width of the threat tube must be repeated every 50 seconds to insure that no Minuteman could escape Pindown requirement varies from-wing to wing because it is sensitive to the geometry of the wing A wing which is wide from east to west such as Wing 1 requires more bursts to cover the threat tube than one which is narrow such as Wing VI Figure 5-4 However Wing V1 is long in the north-south direction and therefore the bursts must be repeated more frequently because a miSsile launched from the southern rnost part of the wing can traverse the lethal volume generated by the burst in 40 seconds Wings II through have approximately'the same overall geo- metric configuration and require identical pindown attacks two bursts every 50 seconds Table 5 1 summarizes the guaranteed pindown requirements for all the wings under the conditions assumed for the example Table 5-1 SOVIET MINIMUM GUARANTEED PINDOWN REQUIREMENT U Interval Maximum Number of Between Pindown Number of Wing Bursts Bursts Duration Required SLBM Yield 2 2 Mt Minuteman Vulnerability 1 cal cmz 49 DocIdz32700119 Figure 54 Pindo'wn Geometry Wing V1 2 MT Weapon 1 Cal sz U 50 SEER-ET mw# 51551 DocId 32700119 3311 a- gs'VOiume IV - 1 1 cfLETHAL - 139 d l ANGLE SUBTENDED BY 3 EUROPEAN RUSSIA 0 9 50 zsuasm 40 SEC JNTERVAL 100 NOSTH 150 400 500 DOWNRANGEINMI 7 I Volume IV - The pindownrequirernent iswextremely sensitive to the attacker's assessment of Minuteman hardness The number of required varies with the square of the hardness level because a variation in hardness changes both the number required to cover the width of the threat tube and also the time required for Minuteman to fly through the lethal volume Figure 5 5 shews the requirements for a pindown attack at Wing I if the assessed Minuteman hardness is 5 cal cm2 and the have warheads Note that not only are 12 bursts 3 required to cover the threat tube but also that they must be repeated every 25 sec- ends The overall impact of hardness is shown in Figure 5-6 in terms of the number of required per minute of pindown for both 1 and SLBM warheads The duration required for a pindown attack is also subject to some uncertainty arising from the degree of conservatism in the mind of the preemptive planner Given accurate intelligence and high confidence in that intelligence the Soviet planner may realize thattMinuteman could not be launched any earlier than 15 minutes after the beginning of'the attack In this case the pindown duration required is only 15 minutes In the absence of such intelligence it seems likely that the planner would elect to make his pindown as secure as possible by beginning at the earliest possible moment and maintaining the attack until his reach their targets In this case pindown duration is 20 to 22 minutes depending on the location of the Minuteman wing In the subsequent discussion '20 minutes has been used as the pindown duration 5 4 FLYOUT AGAINST A DEFICIENT PINDOWN ATTACK The Soviet planner's totalinventory requirements for a guaranteed pin- down attack can be estimated from Figure If the planner is Willing to accept some risk and assesses Minuteman hardness at cal eniz and if his SLBM warheads have their estimated yield of 1 Mt 20 minutes of pindown will require 600 Oil station within 100 to 200 miles of the U S coast Because it is practical to maintain no more than about two thirds of an SLBM force on patrol at any one time the Soviet planner s requirement for a successful pindown attack under these kIn this case the depth of the threat tube presents a problem as well as the width so tandem bursts are required one located approximately 40 nmi above the other at each of the burst points Soviet ballistic missile submarine operations have not approached this figure Normally less than one fourth of the Soviet missile sub marines are at sea and these do not usually patrol within 200 nmi of the U S coast Reference 1 I 51 Docldz32700119 7 13 791 9 71Volume llINN41-3 175 175 a - VOLUME100 100 100 go 100 200 309 400ANGLE SUBTENDED BY 29 EUROPEAN RUSSIA 300 400- 500 3 DOWNRANGE NMI Figure 55 Pindown Geometry Wing 1 1 MT Weapon 5 Cal Cm 5 2 1 5th pIDca 6 9 0 l 2 3 MINUTEMAN VULNERABILITY Figure 56 Minuteman Pindown Requirements x1If 1 - I sin 120 - 3133PINDOWN DURATIONMAXIMUM 21 MFNUTES -22germ vow - which I if a I a Volume IV circumstances is 900 missiles or 56 submarines At his cui rent rate of production this level of missiles means he could not mount a guar- anteed pindOwn attack against Minuteman for at least five years The possibility that only a few bursts would be required-to discourage flyout was raised in Subsection 5 Z If this were the case then a very small inventory would sufiice to keep Minuteman bottled up and the Soviet planner presumably could accomplish the mission at this time It is the thesis of this section-that such an attack would be extremely risky because there is a irelatively simple flyout strategy which would guarantee that a significant portion of the Minuteman force would sur vive the pindown attack The implementation of this strategy requires no knowledge of the Soviet attack strategy nor does it require any information about the Soviet forces and their capabilities which cannot be estimated with high Confidence based on currently available intelli gence The strategy discussed below is not one that the U S would adopt wil lingly It has a number of drawbacks principal among which is that it would make it very difficult to coordinate the arrival of RV's on niultiply- targeted aimpoints In addition it requires that the NCA respond with out the luxury of a prolonged assessment of the attack although there would be no doubt as to the reality of the attack and its intent However none of these drawbacks are likely to seem sufficient from the Soviet planncr' 5 point of view He must concern himself with what the U S can do because he cannot be sure of what we will do An additional factor in enhancing the credibility of flyout is that the minimum number of survivors is calculable from knowledge of the Soviet inventory alone and is not sensitive to the manner in which it is employed The actual number of survivors will exceed this level if the Soviet attack is less than optimum The flyout strategy is basically very simple Minuteman launches are timed and sequenced in such a way that no pindown RV can possibly kill more than a fiXed number This tactic is'accomplished in the following way at each wing the duration of the pindown attack is divided by the total number of missiles to be launched this factor yields the interval between successive launches Launch sequence is uniformly random 3 over the wing Consider for example Wing assume 20 minutes of pindown a Mt SLBM warhead and an assessed Minuteman hardness of cal cmz Under these conditions it takes Minuteman at least 50 seconds to transit the lethal volume generated by a single pindown burst Because the Minutemen are launched 6 seconds apart 20 minutes divided by 200 missiles 9 missiles at most are potentially vulnerable to the burst of an incoming RV However because the launch sequence is distributed uniformly over the entire wing the likelihood is that no more than three of these will be within one lethal radius of a given burst 54_ DocId 32700119 - - 149 Volume Iv ACDAIST-196 The major reSult of the flyout tactic is that the number of surviving missiles is sensitive only to the number of attacking RV's The attacker can do nothing to increase the number of missiles killed by any given-RV Figure 5-7 shows the effect ofthis flyout strategy on a deficient inven tory pindown attack on Wing I Here the expected number of survivors resulting from flyout is plotted as a function of the' inventory devoted to pindown at Wing I The trends are similar at each of the other wings The data used to generate this figure was provided by a Monte Carlo simulation of the pindown engagement Functions like those in Figure 5-7 were generated for each of the Minuteman wings Each function was approximated linearly using least- squares approximation then the resulting linear functions were used as payoff functions to determine an allocation process for a deficient inven tory attack across the entire Minuteman deployment The results are shown in Figure 5 8 Figure 5 8 plots the number of Minuteman saved by flyout as a function of the SLBM inventory which the Soviets devote to pindown The second aryabscissa on the figure indicates the number of the Soviets would require in order to have the associated pindown capability The scale on this axis incorporates the following assumptions concerning availability and utilization A No more than two-thirds of the force is on station B SLBM availability reliability is 80% C At least 50 time-sensitive targets will draw SLBM attack these would include SAC bases and central command installations Washington D C NORAD Headquarters etc Figure 5-8 illustrates the folly of a pindown attack with an inventory that is not adequate to guarantee the results The importance of this figure and the flyout strategy as a whole is not that the U S would want to employ such an option rather it is that it is wholly credible that the U S could employ such an option any nation planning a preemptive attack on the Minuteman must recognize this credibility and accept the possibility that a preemptive strike against Minuteman may fail com pletely if not supported by an adequate pindown attack As a final point recall that the requirements shown in Figure 5 8 are minimums and assume a larger than-cstimated warhead and a Soviet planner banking on U S sure-safe levels as adequate for his kill This weighs the game heavily in favor of the attacker If instead one were to use moderately conservative assumptions Soviet point of View the requirements for an adequate pindown attack become 55 DocIdz32700119 99129 plaoa 6 100 LEE QD 50L DURATION - RVYEELDMINUTEMAN VULNEBABILETY - 1o- I 'iz A utmzl 100 Pmnowm ALLOCATED 1 RV's Figure 5-7 Minuteman Saved by Flybut During Attack Wingl 9919 P1300 6 I100 LEE MOTEL DURATIONFORCE RELIABIUTYALLOCATED TO NON MFSSILE TGTSIrv 3 400% - I 15 p- $133 25 LNER 100- 7 200 300 400 500 - TOTAL sown YCLASS SUBMARENES Figure 5 8 Minuteman Saved by Flyout AH Wings U - m 1thsL p vVg 1 - Jams nhii th Volume IV impractically large For example if the Soviets assess Minuteman hardness at 5 cal cm2 which is not impossible or really even improba ble their pindown requirement is approximately 1 900 RV's to insure that no more than 30% of the Minuteman force survives flyout Factor ing in the availability and reliability of the generates a require- ment for 3 600 RV's or 225 ballistic missile submarines If the Soviets were to MIRV their sea-based force it would if anything increase the inventory requirement This rather startling result occurs because of the requirement to cover not only the width of the threat tube but also to cover as long a segment of the Minuteman trajectory as possible The Weight penalty paid in generally tends to reduce available yield by at leat 50% for example if three RV were packaged on the 88 6 each yield would almOSt certainly be less than 300 kt This would give each warhead alethal radius of at most 22 nrni compared to 58 nmi associated with the single warhead used in the examples 1 cal cmz Thus the three RV's would give about the same coverage across the threat tube as the single warhead but the time required for a' Minuteman to traverse the lethal volume generated by any of the RV's would be reduced almost by a factor of three The interval between bursts then must be reduced appropriately which in turn drives the inventory requirements up sharply 5 5 VIABILITY OF It is never really possible to state with high confidence what the Soviet assessment of a given situation would be but the numbers which evolve from analyses of pindown requirements are persuasively large and virtually insensitive to qualitative improvements in Seviet systems It is clear that whatever his assessment of Minuteman vulnerability the Soviet planner will require close coordination of a large number of his operating very close to U S coastlines The movement of such forces into U S coastal waters would in itself be a significant departure from Soviet practice and thereby would constitute a potentially pro- vocative act even during a calm period in international relations Dur ing a period of high tension between'the and USSR such an act might be considered a prelude to attack thereby inviting a first strike by the U S At the veryleast it would alert the U S and undoubtedly flush the manned bomber force In summary it appears unlikely that the Soviets will have the capability to mount a Viable pindown attack within the next few years If the U S 'l Until the Soviets deploy missile submarines considerably quieter than their current Y class SSBN the U S could have high confidence of detecting some indication of such an act 58 secesT 11 DocId 32700119 ewwswemm Volume IV - upgrades the hardness Di-Minuteman even modestly Soviet achievement of such capability at any time is unlikely simply because of the shee numbers of that would be required 59 D0cId 32700119 I I i PkVolume IV - Section 6 U S OPTIONS Ii 9 Pindown could be completely discounted as a threat if any one of the following could be accomplished A Hardening of lVlinuteman guidance and the Minuteman post boost propulsion system to 5 cal cmz B An enforceable submarine standoff of 500 nmi would be of great value a 1 standoff would be more than adequate An agreement limiting Soviet SSBN total inventory to some number no more than the U S SSBN force 41 boats This agreement need apply only to Y class or better submarines Hardening of the Minuteman components to 5 cal crin2 is not impossible the guidance set is the most significant problem the booster is already hard to greater than 5 calories and the Minuteman Ill post-boost pro pulsion system could be modified to achieve a comparable level The Air Force has had a guidance hardening development program under way for three years The goal oi this program is a guidance set for future ICBM applications but it will also be compatible with the exist- ing Minutemen Hardness level of this should be in the 2 to S cal cm2 region Operational equipment should be available by the mid 1970's It is also possible to increase the hardness of the current Minuteman guidance through shielding but only at the expense of extra weight and thus a compromise in range Submarine standoff has attractive features as an aid to both Minuteman and manned bomber survivability There are major uncertainties in the ability of either nation to verify such an agreement because of the difficulty of detecting individual submarines on patrol To support a flyout policy however requires only that one of the many submarines which must violate the exclusion zone in order to mounts pindown attack be detected The probability of such a detection is quite high e if the probability of detecting a single violation is no more than 0 05 the probability'of detecting at least one violator out of the twenty or more that would be required exceeds 0 65 Until Soviet submarines become much quieter the probability of detecting a single violator will remain much greater than 0 05 0f 7 6 0 Docld 32700119 an GI si- Volume - An arms control agreement which'placed an upper bound on Soviet SLBM deployment is extremely desirable to eliminate the possibility of a pin down attack It is not clear at what deployment level the Soviets would agree to such a limit however in View of their oft-repeated repudiation of agreements which freeze the situation in an unbalanced position it seems likely that they would hold out for a fOrce at least equal in num bers to the U S fleet ballistic missile force Should this be the case i a modest improvement in Minuteman hardness to less than 2 cal cmZ would be desirable to maintain an assured flyout capability There is one other area in which U S action is required before pindown can be discarded as a viable threat If a flyout strategy is the means for defeating pindowzi Minuteman launch planning Inust contain such an option It is unlikely that such is the case now because the counterforce threat has yet to materialize However within the next few years such an option should be considered Also refinement of Minuteman launch control center operations to reduce the time required to execute the launch command is a highly desirable development provided it can be accomplished without compromising failwsafe precautions 61 DocId 32700119 3' 11 v 35' Volume Section 7 REFERENC ES I Submarine Launched Ballistic Missile System U Defense Intelligence Agency Repert No 31 December 1968 S Submarine Launched Ballistic Missile Systern SS NX- USSR S Department of the Navy Scientific and Technical Intelligence Center Report No STIC -CW- 10 2 71 20 May 1971 S USSR Strategic Offensive Weapon Systems Data Book U McDonnell Douglas Astronautics Company Report No MDC G2289 April 1971 5RD Effect of ABM Systems Against SLBM Attack on SAC Bomber Bases U General Research Corporation Report No February 1970 S U S Strategic Offensive Weapon Systems Data Book U McDonnell Douglas Astronautics Company Report No MDC 32288 April 1971 SRD Physical Vulnerability Handbook Nuclear Weapons U Defense Intelligence Agency Report No 1 June 1969 C Command and Control Systems U 'The Boeing Company Report No D2 31638 l ' Revision A September 30 1967 U Minuteman Vulnerability Specification BSD Exhibit 63 673 U Ballistic Systems Division Air Force Systems Command 4 Febrtiary 1966 5RD a 62 51551 Docld 32700119 5 vi Volume IV Appendix A MINUTEMAN PROPULSION AND STRUCTURE VULNERABILITY A I INTRODUCTION AND SUMIVIARY The Minuteman ICBM is a retaliatory weapon designed for launch against enemy targets in the event of a first strike against the United States Its effectiveness as a deterrent and credibility as a weapon is dependent on its ability to fly out of its silo during an attack survive the effects of pin-down bursts of nuclear weapons and deliver its pay load on target An important parameter that determines the likelihood that the vehicle will successfully complete its mission is its hardness tothe effects of pin down bursts This appendix presents the results of a limited study of the vulnerability of the Minuteman II and Minute man propulsion systems when exposed to weapon fluences up to 10 cal cmz Overall vehicle system hardness as it is influenced by systems and other than propulsion is considered in Appendix B Minuteman uses a three-stage solid propellant booster to accelerate its payload into a ballistic trajectory A post-boost propulsion system PBPS aboard the payload bus provides a final maneuvering capability for weapon delivery The present vulnerability study examined the propulsion systems for each booster stage as well as the PBPS to estimate a sure safe xn-ray fluence level for which the probability is high that the propulsion system would not be damaged enough to pre vent the vehicle from completing its mission The three booster stages Were found to be inherently hard enough to survive an X ray fluence of 5 cal ensZ over a 1 to 15 Rev blackbody temperature range of x-ray energy spectra This result is based on damage criteria that are viewed as sure safe i they are conservative Thus it is pos sible that a more detailed study would establish a higher inherent hardness level approaching 10 cal cmz particularly if test data could be procured to substantiate a less stringent spall criterion for the third-stage fiberglass case I The PBPS poses a more difficult problem in predicting survivability at fluences exceeding 1 cal cmz A careful and detailed analysis of the Minuteman PBPS performed by Autonetics Division of North American Rockwell Corporation led to the conclusion that the PBPS would meet the Air Force SAMSO requirement that it be hard to at least 1 cal cm 63 1 1 Volume IV - Reference However the report did not go on to predict the maxi- mum level to which the PB PS might be safe A later study at Reference performed to the Air Force Rocket Propulsion Labora- tory included a vulnerability assessment of typical rocket engine components whichmight be used for a liquid propellant PB PS detailed drawings of the Iviinuteman PB PS wei not made available 01 the study as originally intended The study showed that most components were held to ray finances of 5 to 10 cal c1712 those not 1nhe1 ently hard to better than 1 cal c111Z could 1eadily be protected by a small amount of shielding or minor redesign to increase their hardness to this level The su1e safe analyses pe1 01 med to date have been con servative and consequently the PBPS is probably actually har dei than estimated and can certainly be made harder with relatively little effort A summary of the results of the MDAC study of PBPS com ponents clearly shows the large range of uncertainty between the relatively certain bounds represented by sure safe and sure Jail levels This spread is caused by the difficulty inherent in per 01m1ng an analy sis when there is little test data available 01 guidance The sure safe level is conse1vatively estimated to be at the point of incipient damage and in many cases is probably well below the level at which failure would actually occur Thus it is reasonable to believe the PB PS components could be relatively easily haidened to an x ray fluence as great as 5 cal crn2 A study is presently underway at MDAC Refe renceA 3 on the weight and cost penalties which may be expected in hardening existing 1ocket propulsion components to fluences as high as 50 cal c1112 Infmmation- compiled in this study will aid in predicting the cost of hardening the PBPS to a sure sale level of 5 cal cmz This information will be available around the middle of-1972 A 2 VULNERABILITY EVALUATION The major nuclear threat to missiles which operate in the exoatmos phere is from xvrays This is indicated in Figure A l which presents the altitude dependence of the free field environment for a 4-Mt weapon The figure shows that at altitudes above 100 000 ft x-ray effects pre dominate while at lower altitudes the x rays are attenuated by the atmosphere and neutron and gamma ray effects predominate Earlier studies Reference have shown that propulsion systems are not susceptible at the threat levels of neutrOns and garnmas which cause failure in other more sensitive missile components such as electronics and warheads The major threat to propulsion is X ray induced damage that occurs at altitudes of 100 000 t or higher The present evaluation of the booster stages was thus limited to potential x ray damage at fluences of 5 cal c1112 and 10 cal c1112 over a to 15 kev range of black body energy spectra Potentially critical areas of damage were noted for each stage then evaluated on the basis of data presented in a design 64 m DocId132700119 - Volume IV - - 4 71 1 I l' Mr 5 400 X-RAYS to NEUTRONS - 1014 NVT 2 104 RAD sn PROMPT GAMMA 200 KT MACE - k 4m 1 BLASY 4 PS 0 I CO-ALTITUDE RANGE 1 600 FT 0 100 200 5 300 SRO-1 Figure Altitude Dependence of the Free-Fieid E-H Mironment for a 4-MT Weapon U '15 W- WW ATOMIC ENERGY DocId 32700119 Volume IV handbook prepared for the Air Force ReferenceA 4 and data prepared as part of a current hardening study being performed for the Air Force ReferenceA 3 Potential failure mechanisms were postulated as f'ol ' lowsf Previous analyses have shown these mechanisms to be the critical ones that determine propulsion vulnerability at the threatievels considered here A Motor case wall heating due to in-depth energy deposition Motor case front surface spall due to stress waves C Motor case back surface spall due to stress waves D Case to liner bond tailure due to stress waves E Linerato grain bond failure due to energy deposition in grain - F Structural damageto nozzle due to blowxoff impulse loading Nozzle throat insert damage due to up mthe nozzle exposure causing surface damage and debonding H Grain damage due to upwthe unozzle exposure and energy deposition in grain The case Inaterial and wall thickness or each stage were taken from sheets in the Solid Propellant Information Agency SPIA motor n'ianual ReierenceA-E and are tabulated in Table The data sheets showed that each stage was coated with a thin cork or rubber insulation to limit temperature rise of the case due to aerodynamic heating For the vulnerability evaluation it was assumed the insulation was completely charred and ineffective as radiation shielding by the time the second stage ignited at about 100 000 ft altitude It was also assumed that the thrust vector control components cold gas valves piping and tanks are of a hardness equivalent to that of the propellant valves and cone spheroid tank evaluated in the MDAC PBPS analysis described in Ref erenceA Z and are safe to 5 cal cm2 or better unless their electrical controls have soldered joints which are not shielded by enclosures requiriring a minor fix Copies of the xwray energy deposition curves and induced stress wave curves used for the evaluation have been abstracted from References andA 4 and are presented in this report W'here data were not available for the precise material used in Minuteman data for a sii nilar material which will provide similar results have been used For example energy deposition curves for A286 steel have been used for the Ladish of 66 Docldz32T00119 Jenuepudno a ed 5m L9 Table MINUTEMAN MOTOR CASE DATA U her glass Estimated Wall Wall Liner Case Insulation Stage Material Thickness Material Liner Thickness Insulation Thickness Minuteman II 1 Steel 0 147 Buna N G 065 AVCOAT II 0 070 Ladish 373 cm glass 165 cm 178 cm D6AC phenolic carbon phenolic 2 Titanium - 0 104 Silica 0 030 AVCOAT 085 - 0 105 264 cm loaded 076 cm 216 267 cm nitrate rubber 3 5 994 0 120 Silica 0 030 51 410 El 0 10 - 0 370 Fiberglass 305 cm filled 076 3 58 cm Silica filled 254 940 cm 2 Buna S buna Scork Minuteman 3 5 994 0146- so 851371 cm 0635 cm 2755 Cork 229 cm Fiberglass silica rub 96L lsNoov - Gammon tenuapuuoo 939d SM 4 11Il Volume IV the first stage and energy deposition in a PBPS solid propellant has been used to estimate deposition through the case wall into the Minute- man booster grains A 2 1 Motor Case Wall l leating Results of the evaluation are tabulated inTableA 2 and show the wall temperature rise 01 ll stages to be within the sure- safe criterion of 500C for a 5 cal cm fluence at the worst x-ray energy spectrunu between 1 to 15 kev The temperature rise is that corresponding to the inner motor case surface and the criterion of is based on estimated incipient damage to the case liner bond This is more critical than case sti loss due to temperature rise The table also shows how shallow is the depth of material whiCh is melted and removed by surface heating and thus is not critical in reducing case strength At 10 cal 'cniz stages two and three of Minuteman II barely exceed the sure safe criterion The temperature estimates used in -- the analysis are given in the curves of Figures through Quasi equilibrium temperature rise in the motor case wall is read directly from the curve for the appropriate material and thickness The- criterion used for surface melting and material removal is the energy in cal gm needed to raise the material from romn temperature to itsrnelt temperature It is assumed the melted material is thrown from the surface as the compressive wave generated by in depth heat ing is reflected from the front surface of the material The material removed is' 3 mils or less and is not considered enough to cause failure of the wall A Z 2 Motor Case Front Surface Spall Table also contains the tabulation of response of the motor case wall to front surface 5235111 and back surface spall It shows all stages to be safe at 5 cal cm ray fluence and the metal cases to be safe at 10 cal cmZ The fiberglass cases for the third stage however exceed the allowable 1 Kb peak stress criterion at 10 cal cmz The 1 Kb cri terion is based on incipient spall of the phenolic binder in the wall and not spall of individual glass fibers It is thus possible that damage to the wall at 2 Kb may not be deep enough or severe enough to cause the motor case wall to fail and the case would thus be safe to at least 10 cal cmz Lacking data to prove this to be true it is prudent to limit the sure safe fluenceto 5 cal cm The peak stress values weie taken fr om l igures A 5 through 7 showing peak stresses calculated with the PUFF hydrodynamics code for steel titanium and fiberglass Peak front sulface sti ass was determined by reading the peak tensile stress in the material at the front surface and then corwerting the stress reading from the fluence 68 DocId 32700119 PIDDU 6 11001 39 69 Table MOTOR CASE WALL HEATING AND SPALL U Damage at 5 cal c1112 Damage at 10 calicmz Sure- Estimated Estimated Depth Estimated Estimated Depth Safe Maximum Of Material Maximum Of Material Failure Mechanism Criterion AT Removed AT 0C Removed cm cm k Motor Case Wall Heatinr Minuteman II 'tage one 5teel 373 cm AT 20 0006 00024 25 0012 0004 Stage two Titanium 264 cm AT 35 001 00039 60 0-018 00971 Stage three Fiberglass 305 cm 43'1 1 35 003 00118 55 906 00236 Minuteman Stage 3 1 cm - AT 30 003 00118 45 006 00236 Damage at 5 calicmz Damage at 10 calicm2 Estimated Estimated Estimated Estimated Peak Distance Peak Distance Stress Into Material Stress Intb hiate rial cm cm 2A Motor Case Front SurfaCe Spail liinutentan H Stage one Steel 373 cm00787 00787 gge two Titanium 2600394 00394 Stage three Fiberglass 305 cmkev 04 01574 01574 Minuteman Stage three Fiberglass 371 cm 12 1 0 8 Kb at 5 keir 04 01574 01574 Damage at 5 cal c1112 5 Damage at 10 9 Estimated Peak Combined Estimated Peak Combined Stress at Back Surface tress at Back Surface 2B Motor Case Back Surface Span Minuteman Ii Stage one $tce1 373 cm 15 Rev 8 0 Kb at 15 kev Stage two Titanium 264 cmRev 8 0 Kb at 5 Rev Stage three Fiberglass 305 cm 1 Kb 1 02 at lkev 04 Kb at 1 Rev Ix'linuteman - Stace three Fibez-glass 371 cm 1 Kb 9 Kb att 1 kev 1 810 at I kev 21 231 Kb 900 Psi F For worst case black body 1 to 15 kev spect_rum 2 5These values drop to 0 82 and O 71 Kb respectively at a fluence of 4 germ Wow amnion - - - i 5 1 pageynclassified F Volume _l 800 0 b 0250m F 650 DZF 1- 550 53 3 LU LU LU 3 500 0 450Figure A-2 Temperature Rise for Various Case T'l cknessesmStee 70 This page Unclassified Dar-31d 32700119 5 -- 9 351 This page Undassmed - rlafwe fVoiume 3 iwrr 0 Ibiza mlhf 'Ill5 0 450 AVEEAGE EQUILIBRIUM TEMPERATURE 0 FLUENCE CALICM21 1 60 70 Figure A-B Temperatufe Rise for Various Case Thicknesscs-Titanium 71 This page Unclassi ed 1 Docldz32700119 '15 I 92- waif-1 -- aw-u FINAL AVERAGE EQUILIBRIUM Tem s muqe 350 at 2 avg v 3 This page Unclassified 2 Voium m 1 - r 23 - I - 11 I 800 alf 700 0 05 400% 650 500 0 0 30 CM 450 $1400 i 1000C 0 10 2o 30 40 50 FLUENCE Figure A4 Temperature Rise for Various Case ' cknessesuFiber Glass 60 70 72 This page Unclassi ed a DocId 32700119 I - Volum51551 65 g1 62 a RD DUE - - I unlumn n1 1m 74 AT mir rumncy hr rTfu - - - ind-ts rr a Volume 1v 5155' 1 1 - I - 3 17 7 - s 41 13 napa m-Jm- nscz urw Volume IV noted for the curve to a fluence of 5 cal 2mg For example for steel FigureA S the stress reading is reduced by the factor 05 1 00 to convert from 100 cal crnZ to 5 cal cmz A 2 3 Motor Case Back Surface Spall Back surface spall is also tabulated in Table A-2 and shows the metal cases to be safe to 10 cal c1112 The fiberglass case for Minuteman stage three meets the 1 Kb criterion at 5 cal cmz but stage three of Minuteman II barely exceeds the 1 Kb criterion at 5 cal cmz It does meet the 1 Kb criterion at 4 cal c1112 and is safe at that level In all likelihood the fiberglass case will be safe at 5 cal crn2 since the dif ference between the 1 Kb criterion and the l 02 Kb estimated stress is well within the tolerance of the accuracy ofthe predicted stress To estimate the back sulface peak stress for the metal cases the compressive and tensile stresses are lead off the CUIVGS of FiguresA 5 i and 6 at the mate ial depth equal to the wall thickness The corn pr essive and tensile stresses are numei ically added to obtain peak reflected stress then factored by the fernce ratio as was done above fer front surface stress Fiberglass stress is calculated sonaewhat differently because the peak tensile stress which spalls the wall is a function of the stress which can be reflected from the adjacent liner 'material Thus the peak compressive stress notedfrorn the curves of Figui 7 must be modified by the ratio of the acoustic impedances of is adjacent niateiials for nested cases this factOr is insignifi- cant The expression used isWhere Pr Reflected tensile stress Po Initial compressive stress pt 2 Fiberglass density '00 2 Liner density Ct Acousticvelocity in fiberglass C Acoustic velocity in liner 0 For the present calculation the following values for the fiberglass wall and liner were taken from Reference 4 and used as rep e sentative values 76 DocId 32 00119 a sum - is - Volume iV 0 PC Si locen rubber liner 1 4-2 l 38 105 GE Phenolic fiberglass 1 91 6 36 105 Thuswhere Po 2 1 6 Kb for Minuteman II stage three 30 cm wall P0 1 4 Kb for Minuteman stage three 37 cm wall nan-d the reflected tensile stress is Minuteman II Minuteman 4 98 4 98 Pr 1 024 Kb Pr Thus both Minuteman II and Minuteman Ill meet the sure-safe criterion for a fluence of 5 cal c1102 for not causing back surface spall of the motor cases A 2 4 Case-to Liner Bond Failure Failure of the case to liner bond due to stress waves can lead to failure of the case from overheating by burning propellant Scaling data pre- sented in Table XXVII of Reference to the fluences of interest the peak tensile stresses in the bond wereestimated All stages as shown'in Table were found to be safe to at least 10 cal cn xz These results are considered reasonable on the basis of tests of similar- bonded specimens Reference A-6 which showed the following - Case to Liner Bond Material Material Failure Level Thickness Steel I 6 7 cal c1112 at 8 kev 63 cm Titanium 7 9 cal Crnz'at 8 Rev 28 cm Fiberglass No Damage 35 cm Fiberglass No Damage ' 74 cm 77 DucId 32700113 PIDUG a li EIIODLZE 8L 4 Table CASE TO LINER BOND U Damage at Damage at 5 cal c1712 10 Cal crnf2 Mater- Sure Estimated - ial Estimated Safe Peak Stress Thick Peak Stress Material Critical Areas Criterion Tensile mess Tensile Thickness Kb cm Kb cm Case To Liner Bond Failure Minuteman II Stage one Steel 373 cm 1 Kb 09 15 kev 20 17 15 Rev 20 Stage two Titanium 264 cm 1 Kb 09 15 k ev 135 15 kev 135 Stage three Fiberglass 305 cm 1 Kb 23 kev 20 45 kev 20 Minuteman Stage three Fiberglass 37l cm l'Kb 23 1 kev 20 45 lkev 20 germ Vow ew moA' Volume iv - s- From these tests it would appear evident that the case to liner bond is safe to better than 5 cal cniz It is possible the bond is good to levels exceeding the 7 and 8 cal cmz shown since there is evidence that the bonds tested did not develop their full strength potential A 2 5 Liner to Grain Bond Failure Evaluation of the liner to grain bond shows the dose to be less than the damage criterion of 106 rads at 10 cal cmz for all stages of the missile The values shown in Table Full were developed from the X ray energy deposition curves of Figures through Using these curves the dose to be expected in a typical motor grain shielded by various motor case materials and thicknesses is shown in the fig ures The dose in cal gm per cal crnZ is read directly from the curves and then multiplied by 4 105 rads per cal gm to convert the dose to rads The results are tabulated in Table Awtl A Z 6 Structural Damage to Nozzle A possible source of damage to all stages of the Minuteman booster is structural damage caused by excessive deflection of the motor case or nozzle structure due to blowoff impulse The current MDAC study of propulsion hardening techniques Reference A43 has determined that the integrated structure of case liner and grain for thin wall motor cases is resistant to structural damage at fluence levels in excess of 20 cal cmz Therefore this analysis was limited to evaluation of the nozzle exit cones The exit cones of the exhaust nozzles of all three stages are unshielded by surrounding structure particularly in the event of illumination from the rear The assumption was made that the exit cone materials were silica phenolic composite materials They were analyzed using the single zone approximation given by Equal tion 3 3 of Reference A-4 This showed as tabulated in Table that the exit cone impulse is well below the sure safe criterion of l 000 taps 1 tap dyne-sec cmZ at a fluence of 10 cal cmz Calculation of the estimated impulse the exit cones will experience is as follows From basic material data the density and sublimation energy for silica cloth phenolic are obtained From the deposition curves of Figure 1 energy deposited and the depth of the affected zone are obtained for 1 Rev the worst case for producing blowoff impulse Thus the blowoff impulse in taps is given by 1B 79 DocId 32700119 08 Table A-4 GRAIN TO LINER BOND U Deposition Through The Case Wall Into The Grain Sure Safe Dose at Dose at Critical Areas Criterion 10 cal cm 5 cal c1112 Rads RadS Debond of Grain to Liner Bond Due to Grain Failure Iviinuteman II Stage one Steel - 373 cm 106 I 3 15 104 1 53 x104 in Grain Stage two Titanium 264 cm 106 Red 1 18 x105 5 9 104 in Grain - Stage three Fiberglass 305 cm 106 Rad 3 15 5 105 1 58 x105 in Grain - Minutemen Stage three Fiberglass 371 cm 106 Rad 3 02 x105 1 51 x105 in Grain 1cal gm 4 2 x105 rads mi Voiume lv 14' Figure A-B Energy pe osition in PBPS Propqilant Surface Under Steel and 2 54 cm LI-ner 81 555 51551 @15555552355551165 5 -RD DUE 2 gure In PBPS Propellant Surface Under Fiber Giass find 254 cm Liner U 82 l I 42 21626 - RD DOE D0cId 32700119 rm ENERGY Volume 1V - 196 I A1hl1lf if I j 42 USC 2162 a - RD DOE DocId 32700119 I PIDGU 6 IIDOLZE i713 Mr Table I 7 '5 NOZZLE STRUCTURAL DAMAGE U Calculated Impulse Critical Area Sure Safe Criterion at 5 cal cmzr at 10 cal C1112 Structural Damage to Nozzle 7 9 Minuteman II 5 1 Stage one Stage two 1 000 Taps 251 Taps 964 Taps 8 Silica 3 Stage three Phenolic 594 Exit Cone C33 Minuteman Stage three I 47 5 31 43 SariATOMIC ENERGY Ac7m1954_ n - jg ivomme tv 1A00NST-196 gure 11-31 Energy Depnsitmn in Silica Phenolic Nix-26002w 51%ffb 3 g Zf ggb1 1 D0E asses - I 9 Volume IV Where Material density grnj cnog ES Energy to sublimation for the material cal gm AX Thickness of affected zone cm Total energy deposited in zone cal gm For silica Cloth phenolic 1 26 gm cm3 and ES 2 738 cal gm _Fron 1 Figure A-ll the following values are obtained 5 cal end2 10 cal om2 AX 00073 cm 6x 2 0016 cm l 5 cal cm2 - 7 The values are taken from the intercept of the 1 kev close curve solid line with the dose at 147 6 cal gnu per cal 21112 for 5 cal CD12 'fluence and 73 8 cal gm per cal c1712 for 10 cal 21112 fluence The same intercept point the thickness intercept with the dashed 1 Rev line then provides the energy summation for each flue-nee Fluence multiplier by the energy summation value gives the above values for H The formula can now be solved at 5 cal cm2 150 J1 26 5 738 1 26 00073 251 taps at 10 0016 964 taps Since the calculated impulse is less than the 1 000 taps criterion the nozzle is estimated sure safe to 10 cal c1172 fluence A Z 7 Nozzle Throat Insert Damiano It Is estinlatecl that the nozzle throat insert can survive an x-ray fluence of 5 All the nozzles of the three stages of the booster 86 DocId 32700119 jw 131 1 1 1 - Volume -IV - are fabricated with tungsten throat inserts Tungsten is a high atomic number material which readily absorbs incident x-ray energy It is therefore generally considered a sensitive material to choose for use in a vehicle which will be exposed to the effects of a nuclear weapon - An analysis of a rocket nozzle with a tungsten throat performed as part of a study for the Army Materials and Mechanics Research Center Reference showed the sure-safe level of the tungsten to be less than 5 cal cmz The analysis was based on hot tungsten the meter was operating when exposed and an exhaust gas area density of 7 1 0'2 grin cm2 which shields the nozzle throat from low energy x rays The damage mechanisms investigated were insert surface damage and debonding of the insert from the nozzle due to stress waves A nozzle of the same design exposed to high energy 9 to 20 kev 1 x rays in an underground test at a fluence of 23 cal cmz showed only very slight surface pitting and no sign of damage sufficient to cause the insert to fail The nozzle was tested when the material was cold andwit had no protective shielding by combustion gases The shielding that a nozzle throat insert receives from the combustion gases is a function of the gas density but more importantly the dis tance the x rays must travel through the gas before reaching the throat This is a function of nozzle size and the Minuteman nozzles are longer by a factor of 3 to 4 than the nozzle which was analyzed Since the nozzle in the underground test survived an actual exposure at 23 cal cm2 of high onergy xaray and since the combustion gases in the Minuteman nozzles would act to screen out low energy xways and leave only the high energy throat it is reasonable to assume that the Minuteman throat insert would survive a fluence of 5 cal c1112 less than one fourth the fluence to which the test nozzle was exposed I - A Z 8 Grain Damage - UpmtheuNozzle Exposure - In the event of an up the nozzle exposure for stages two and three of Minuteman it is possible for x rays to shine through the nozzle throat and illuminate the surface of the grain With the motOr operating some shielding is provided by the combustion gases passing through the noz- zle An estimate of the dose which could be deposited in the grain was Inade by developing the curve shown in Figure from deposition data presented in Figure of Reference The curve shows the estimated dose as a function of exhaust gas shielding and represents the maximum dostor x ray spectra between 1 to 15 v The sure safe dose level for a typical grain is taken to be 5 x10 rads This dose is not exceeded at a fluence of 5 cal c1712 if the path through the 87 W DocId 32700119 9 1 This pageUnctassmed 15 yotume-Iv 32102 I PROPELLANT AAP-3301J 40 1 0 2 0 3 EXHAUST GAS THICKNESS Figure A42 Damage Threshold for lip Nozzie Exposure of Soiid Propellant 88 This page Unclassified DocId 32700119 A D - Volume IV - exhaust gas is long enough to provide 0 2 gm cm2 shielding In the analysis of Reference A-7 the gas thickness was calculated to be 07 grn cn'i2 for a small sho1t nozzle The stage two and stage three Minuteman nozzles are sufficiently longer to provide a multiplication factor of 3 or greater and therefore satisfies the 0 2 gm cm necessary to be safe at 5 cal cmz 9 Post Boost Propulsion System PB-PS Vulnerability Detailed analysis of the -Minuteman post boo st propulsion system to determine the suremsafe fluence level of the PBPS requires more inf01 mation and time than was available for this evaluation At this time the best estimate of PBPS hardness is that it is safe to at least 1 cal c1112 This was the conclusion of the Autonetics study Ref- erence A l performed for SAMSO However the study did not go on to'estinnate a maximum sure-safe level for the PBPS and to do so would require detail design information which is not readily available Consequently the most that can be said is that the PBPS is safe to 1 cal cnnZ but is probably safe to or can easily be hardened to a higher level approaching 5 cal cm This estimate is based on the study of typical PBPS components MDAC performed for AFRPL Ref- erence and the results shown in Table A-6 The MDAC study showed that most components were hard to better than lcm Crnz and wherc extrenu irsoftthey could readily be hardened through simple redesign or replacement of vul- nerable materials with harder materials For example replace teflon bonding with a differ ent bond material or use welded instead of sol d01 ed connections for electr ical systems The study also revealed a very lar ge unknown area between the fluence levels at which incipient damage occurred and the fluence levels which clearly rendered a component inoperative When incipient damage is estimated to occur at a very low fluence level it is probable that the component could withstand more than just incipient damage without failure This would have the effect of narrowing the gap between sure safe and sure fail and increasing the sure safe fluence level For this reason the PBPS is estimated to be harder than 1 cal cm2 and readily shielded or modified to harden it to 5 cal cmz A 2 10 Summary In summary the propulsion systems of the three stages of Minutes man ll andMinuteman are safe to 5 cal cm2 at the woi st black body temperature between 1 and 15 kev Small components such as those in the thiust vector control systems or re ve1 se thrust motors are probably inherently hard or are small enough to be shielded to 5 cal cm at minimum penalty Finally the PBPS is safe to at least 1 callcm2 but is p1obablyha1d to 5 cal c1112 or more 89 SEER-FF DocId 32700119 6 II 19919 PISOG EIIOGLEE 06 'Ir' 1 is 5 nudi Table page 1 df Z PBPS SURVIVABILITY AND HARDENING SUMMARY U - I sumloA 1 I I I I Damage Threshold I Failure Made 3 Failure Criteria Surc Sanc Sure-Kill I I I Fluencg X'ray BB Fluencc X- ray BB - I Component I Survive I Part I Mode Sure Safe I Sure-Kill cal cm Ich cal cmz ch Hardening Recommendations I No Tunk Ichond X-ray lncipwn I Snail m tnnk back 2- 1 300 I Te on lipgr limits Positive I cfion I I demand I surface I41 I I 5-15- Otner m t'hcild of I bond JED-7- ka I prcv_ent1ng ragm shppagr I I shou c be employedneed for bond'3xplosivc I No I I Detona- Xcray I 5 cal gm I 15 catlgm 3 3 15 5 I 15 Add thermal shield to explumvc Iactuation I lead axidc ition I 5 int I lead azidc also shock isolate or Ivalvu I I I I I replace lead azidc by organic I a i I i exploaiVC i i I Cone sphc701di Yes I INone I i hone prapcilant I I I Hank Retainer 2 Melt Dray l cipient mail Congpiete melg - I 1-5 I r100 1 Mutiny lower sugfport plate design I ham eng m I 4' cm I AXHJ 10slant perforations and I hru shie zd retainer screen $1191 405 I Molt X-ray Incipient mcit Substantial melt 3- 1 10 30 l I 5 catalyst I of iridium 3 y 3IaTziam'DCI IFractuz e X-ray Fraczurc of i chere fracture 15 7 0 15 I i I Iridium i 70 cal gm I 7 chI'quHeat shield I Melt X-ray Mei II Cempintc melting 0 4 1 1500 1 Increase heat thinkingprevent total melting Eugene heat shield against Impulswc loading - i I Impulsive X-ray Impulsive load- impulsive wading 4 I 0 5 300 0 5-1_ 0 1 load - in 130 taps 1900 taps 6 I EFuc' v'aive 3 No Solder II Spall X-ray incipient spall I 5113 ElI mifmte high 0 I I joim I I4 6 calfgm 46 calfgm I hxcla by4ncreasm cover I I I I thickna Pintlc and i Heating X-ray Hnatin to Heating 0 100 1 3400 3 1 5 chIaCc 9 Kcnamctm Poppg-s I valve I sent I an 8-0 5 30 I and seats With adequate lowur material I I throngh 0 15 cm 30455 I I i IQSIG FIDOG Am-y# I6 t' I - Table page 2 of 2 Damage Failure Mode Failure Criteria Sure-Safe Sure-Kill Fluencc X-ray BB Fluencc X-ray BB - Component Survive_ Part Mode Radiation Sure Safe Sure-K111 cal cm Cal cma IkeV Hardening Recommendations 3'9 501d Melt X-ray Incipient melt Complete melt 7 9 5 35 5 Same as Fuel Valve valve-1Com i jam cm cm Span X-rny Incipient spall Sevcre span 1 9 5 9 5 024 6ca51gm 0 46ca1 gm i No Coil SurfaCe X-ray Heating of mag Surface apo ization 5 6 6 100 145 Increase thickness or motor cover assembly vapor- aw net to cm magnet ion A cm i 1 10 C051 COPPE Mel X-HY Heatinu to incipient melt 5 S 25 5 8 Use wire knsulation with high I wire cm temperature r incr easc cm thickness of mator cover 3000-11 a No Cast Debond X-ray Incipient chonding 1 3 I 130 'l 1 Nu hardening advanced thrust i Emulation from case - dcbonding l kal 9 5-9 90 5-9 biptopcllani Injector 'Men arc Jay of 10-3 cm Melt of in 2 cm 7 1 man 1 With the passiblc exception of me I ihicknegs thickness 5 5 60 5' Fiberi te insulation the 11 9 7-5 9 engine can probably survive i 5 38 15 10 of X-rays Norm the - M n mtcrials are particularly sewsiz n-rc 1 NO X ray Of 10% Mullra iation dagradation Eiinlina- msuaanon thickness le - hem of reomremcm Aor Humbug cnthe nun-czar Aould e1 m narchcatmg A 3 problcniif Fi5eritc insuiation is - No Injt'ctor Debond Xfray Injector surface Surface temperature 35 250 1 dcbondud lnsulaiion tom crature to at malt Fiberit 500 0 250 cal gin 4 1 9 21 3 9 3 8 8 15 63 IS- mam-5 cm Pressuriza 3 Yes Teflon boot Radaation Xuray 10 rad ID7 rad 200 1-5 400 1-15 None sure-safe criterion is tion system - I damag 14 9 13 053ny very i1 4 15 est-iswoov - emnIOA 7 1 i 23 3 - This page Unclassified Volume 11 - 101 3 REFERENCES A-l x F inal CDR Repelt on Posthoost P1 opulsmn System HardnessTU Autonetics Division of North Anderican Rockwell Report No C8 529 601 Ap1i11968 A1-2 Nuclea1 Weapons Effects on P10pulsion Systems Volume Survivability of Post- Boost Propulsion Systems U 3 - McDonnell Douglas Report No 63144 May 1969 Current Program Analysis and Verification of Nuclear Harden- ing Concepts for Rocket Propulsion Systems U AFRPL Con tract No Nuclear Weapons Effects on Propulsion Systems Volume I - Data Compilation and Designing Guidelines U McDonnell Douglas Report No 63142 May 1969 Solid Propellant Info1 mat1on Agency Motor Manual Data Sheets 9 Elect1 on Beam Expe1iments on Missile Propulsion Corn ponents U Physics InteJ national Company Report No August 1970 D Hardened Components fo1 Interceptm Systems 'lask A - lmp10verl Spa1tan Thiml Stage Nozzle Materials Investigation U McDonnell Douglas Repmtl No AMMRC CR 70 01 Anny Materials and Mechanics Research Center Watm town Mass June 1970 92 This page Unclassified - u - DocId 32 00113 i 1 A Volume IV Ascent 31196 APPENDIX MINUTEMAN GUIDANCE AND CONTROL VULNERABILITY This appendix deals with the vulnerability of the Minuteman guidance and control system during launch The lethal mechanisms are described along with their impact on the critical elements of the Minuteman 6 3 Also the design hardness criteria for iMinuteman are presented Directions for further hardening are discussed briefly but no attempt has been made to estimate the ultimate hardness of the system This appendix relies heavily on Reference B l for Minuteman vulnerability data 1 NUCLEAR WEAPON LETHAL MECHANISMS There are five basic categories of lethal emissions from a nuclear detonation -gamma radiation neutrons thermal radiation electro magnetic radiation and debris These affect the Minuteman system in two basic ways Joy the rate at which they impinge upon the system or by the total dose absorbed by the system The effects of-neutrons in particular result from total dose absorbed rather than the rate but the effects of gamma rays and thermal radiation which is almost entirely in the form of X radiation in the exoatmospheric region result primarily from the dose rate - The nuclear environments that the Minuteman launch vehicle must with- stand design criteria are shown in Table taken from Reference B-Z Survival in these environments is defined to mean that exposure at these levels shall not result in a system CEP degradation of more than 425 ft based on a 90-day calibration cycle The criteria specified in Table 3 1 are considered the most critical Such effects as air blast thermal radiation at wave below X radiation beta particles gamma dose and debris are not important in comparison to those listed Tech- nical terms used in Table B-1 are defined in the glossary at the end of this appendix B 2 WEAPON EFFECTS ON MINUTEMAN Each of the nuclear weapon environments affects the system in a dif ferent way and different elements of the system are most sensitive to each effect However the electronics are definitely the most 93 DocIdz32700119 it I tests P1000 GIIOOLZE -v ht tlu l'XH it w'lnm a 176- Tabie 13 1 - ASCENT PHASE NUCLEAR ENVIRONMENT U BSD 63 6713 Environment Paragraph Criterion Prompt Gamma and 5 1 450 rads 1 Mev effective in 10 8 sec Penetrating X Rays Source Temp 5 Kev or 50 rads 1 Mev effective in 10 8 sec Source Temp 35 Kev Fast Neutrons 5 2 1012 neutrons cmZ at 1 Mev effective damage equivalent X Rays 5 3 1 cal cmz in 10 8 seconds from Sources at 1 to 15 Kev and Special Spectrum to 115 Kev Electromagnetic 5 4 1 30 000 volt meter peak electric field Pulse Gamma- EMP 80 ampere turns meter peak magnetic field 1 gauss peak magnetic flux density Electromagnetic 5 4 8 000 volt meterpeak electric field Pulse no associated magnetic field Prompt Gamma X Rays 6 1 One exposure to the maximum environ and Neutron Multiple ments specified above plus nine exposures Pulses reduced by a factor of 25 EMP Multiple Pulses 6 2 One exposure to the maximem edviron ments specified above plus nine exposures reduced by a factor of QSL-lS vadv - awash x p assess We - Volume iv vulnerable part of the system Table summarizes the weapon effects by component The effects are discussed in somewhat more detail below B 211 Prompt Ionizing RadiatiOn I Because their influence and impact are essentially the same gamma radiation and the higher energy components of the radiation will be discussed together There are two aspects of the environment the total dose and the dose rate- but for the quantities involved here the total dose absorbed is far below the threshold of permanent damage and therefore need not be considered further On the other hand prompt ionizing radiation from a nuclear burst is delivered at a high rate The major effect of this high dose rate is to produce ionization in various materials which causes current and voltage changes in electronics The threshold for such effects is generally considered to be about 107 1ads sec Effects are observed in discrete components such as resistors and capac1tors but the most sensitive components are semiconductor devices The principle effects are due to excess charge carriers generated throughout the materials by the ionization processes The charge carriers are separated according to existing fields and result in transient currents that may cause secondary cur rent surges There are three potential deleterious effects of the increase in current resulting from the prompt ionizing radiation 1 generation of erroneous information 2 burned out or over heated components 3 latch-up a change of state which can occur in integrated circuits where reverse bias is used for isolation at junctions latch up can cause additional current surges and destruction of the integrated circuit Shielding against gamma and high energy x radiation is impractical because of the excessive weight penalties involved Therefore harden- ing against these effects requires use of radiation resistant components g dielectric isolation in integrated circuits and where possible circumvention With respect to the computer circumvention means to prevent the computer from acting on erroneous data resulting from the prompt radiation by turning the computei off during the critical period then correcting for the down period when the threat is past This technique unfortunately results in a degradation of the CEP as information missed during the quiescent period must be extrapolated from data'obtained in succeeding equivalent intervals This technique is currently employed on Minuteman II and Minuteman 111 With respect to the electionics in geneiai circumvention can be employed to momentarily remove all pOWer fr om the vulnerable circuit 95 DocI dz32700119 MW tests P1300 9 5 Table -2 WEAPON EFFECTS ON 6 3 BY U Lethal Mechanism Component Electronics Inertial Missile Inciuding Measuring Cables Computer Unit Structure and Wiring Prompt ionizing radiation Current and vol tage surges due to ionization which can cause burnout erron- eous informa tion latch up Neutrons Loss ofgain in semi-conductors Increase for ward voltage drop in diodes X radiation Same as gamma radiation except close is attenuated by shielding Possible thermal mechanical effects at bonds not as critical as impact on electronics Melting spallation and blow-offeffects but at muchhigher levels than elec tronics damage see Appendix A Eiectro Inagnetic Pulse Spurious charges inhigh gain cur rents induced charges on insulator sur- faces Current and voltage surges induced inloops 4 A wriIO x A bui- Volume - 5 elements while the nuclear environment is threatening Circumvention in this application is not as satisfactory as use of intrinsically hardened circuit Components because it introduces a rather significant reliability problem Also not all circuits can tolerate removal of power and return to their proper function B Z Neutrons Theyulnerability of the system to neutron effects is determined by the response of semiconductors because the damage threshold of other electronic components and materials is several orders of magnitude higher The important neutron damage mechanism is the production of lattice defects by collision between fast neutrons and atoms of the lattice Such defects are permanent and depend primarily on the time integrated total neutron flux Certain transient operational effects are also present but these are small compared to the associated gamma ray pulse effects primarily because of the time dispersion of Igthe neutron pulse rThe lattice defects created by the neutron damage result princi- pally in a decrease in gain for bipolar transistors and an increase for- ward voltage drop across diodes Secondary effects are changes in conductivity carrier inobility and doping concentration Shielding against neutrons is not feasible because of both space and weight limitations low-density shielding is effective but large quantities are required Therefore hardening must be done on a component basis and in addition circuits must be overdesigned to provide adequate gain even after considerable attenuation New semiconductor materials are expected to increase hardness significantly B 2 3 XwRadiation A major portion of the nuclear energy from a nuclear burst is in the form of thermal radiation at such high temperatures that most of the radiation is in the x ray spectrum This radiation appears essentially instantaneously 10'8 to 10' seconds consequently the energy is delivered at an extremely high rate Because x rays are strongly absorbed in mate rials any object exposed to the x ray environment accumulates a great deal of energy in its outer layers in minute frac tions of a second This in turn results in a rapid increase in heat content and temperature which in turn can lead to serious damage through melting vaporization structural deformation spallation and internal shock loading Bonds between dissimilar mate rials are par ticularly vulnerable to xnray damage because different absorption rates and coefficients of expansion can lead to debonding 3 97 DocIdz32700119 4 1 4 Volume IV That portion of x radiation which does penetrate to the electronics devices acts inthe same manner as the harder x rays and gamma r ays and this radiation must be added to the prompt ionizing radiation in assessing effects on electronics There are two aspects to the problem of hardening to x-radiation- optimization of shielding and hardening of internal electronics rThe purpose of the shield is to reduce the incident x ray flux to such a level that the total ionizing radiation internal dose rate will not be detrimental Hardening the electronics against x rays uses the same techniques as hardening against gamnaa rays because the effect on system electronics is the same i It is extremely important to minimize the weight of the shield so that missile payload range or both may be maximized There are Several considerations that must be made in optimizing an X ray shield One is the importance of the spectrum of the incident radia tion - In the low energy region of the electromagnetic spectrum where the primary interaction with matter is by photoelectric absorpe tion high atomic number mate-rials are most efficient At high ener gies where the primary interaction is via Compton effect which is dependent on electronic density or mass of material the shielding weight is less dependent on material Therefore the optimum shield for one incident spectrum willth necessarily be optimum for another Within the photoelectric region the existence of photoelectric absorp- tion edges that occur at different energy levels for different materials complicate the selection of a minimum weight shield Because of the greater attenuation of lower energy photons a beam of x radiation tends to become harder greater percentage of more pens- trating radiations i 3 higher energy as it passes through material In addition a consequence of a photoelectric absorption is the almost immediate emission of characteristic X rays fluorescence radiation of somewhat lower energy_than the incident photons Characteristic radiation is emitted at lower energy than the absorbed radiation in a region where the absorption coefficient is lower Thus it is more efficient to use shields made of a combination of two or more materials because of beam hardening and fluorescence effects B 2 4 Electromagnetic Pulse Although the mechanisms are not fully understood electromagnetic pulses are produced by nuclear weapons regardless of whether the event takes place inside or outside the atmosphere In air the principal source of electromagnetic fields is the gamma radiation which initiates a current of electrons with primarily outward directed velocities This phenomenon appears as a rapidly expanding shell of negative charge When asymmetry is introduced by the ground for example in a near 98 DocId 32700119 - Volume IV - surface bur st _ an electromagnetic pulse is propagated outside the immediate burst volume The magnitudes of the electric and magnetic fields can be significantly greater than those encountered in electrical storms Areas of vulnerability include system cabling and interconnections computer memory high-impedance high-gain circuits components employing high permeability materials and large surface insulators where an electric charge may be stored Interconnecting cables pose potential vulnerability due to the possibility of the creation of relatively large area loops Magnetic field loop coupling will induce voltages proportional to the area enclosed by the loops Such voltages may appear as spurious signals or even cause breakdown of cabling insulation In addition if ground loops of significant area occur large currents may be induced in the circuit that could cause system failure interruption or excessive noise Common electromagnetic interference EMT shielding procedures pro adequate protection from the effects of the electric field of the electromagnetic pulse In the absence of large holes the missile skin provides essentially all the electric field protection needed However all openings in the outer skin mu st be covered with shielding material equivalent to the missile body section In contrast magnetic fields are not well shielded by materials and thicknesses quite adequate for the electric field protec- tion Therefore some of the Inore sensitive components and systems may require additional magnetic shielding In addition to shielding large area circuit or ground loops must be eliminated or the area mini- mized because the magnetic coupling is proportionallto the area of the loop B 3 SURVIVABILITY The survivability of the Minuteman during boost phase is of course determined by its weakest component For both Minuteman II and Minuteman the electronics in the guidance and control 2 - are'clearly the most vulnerable parts 'of the system Table 13 3 sunn marizcs the results of Appendixes A and B showing the vulnerability of the major to X radiation Reasonable modifications to the Minuteman post boost pro ulsion system discussed in Appendix A could result in a S cal cm sure-safe level for that Maximum sure safe levels for the guidance and control utilizing only modifications are probably not large On the other hand replacement of these elements with intrinsi- cally harder elements could ultimately raise the to a level compatible with the other 99 ECHEI Warns a 15 -- - um DocIdz32700119 on tests plsaa 6 IIOOLZE UOI 116 Kev 2 MINUTEMAN VULNERABILITY Current Potential Sure Safe Sure-Safe System Level Level cal cmz cal cmz Minuteman II Propulsion System 5 5 Guidance and Control -Minute man Propulsion System 6 - 7 6 7 PBPS 1 5 Guidance and Control -- Feasible modifications $31 to 5 Kev blackbody to 15 Kev blackbody and special spectrum to germ vow - m awn'IOA or B 4 LOSSARY B-a Blackbody Blackbody Spe ctrum Bl-owoff Impul se Gompton Effect Dose Do as Rate Electron Volt Fast Neutron Fluence -r Vosumew AcoA ST-ms A unit of pressure equal to 106 dynes cnoZ of O 9869 atmosphere An idealized bod r that absorbs all energy falling upon it It reflects no energy and if at a uni form temperature emits electromagnetic radiation with a distribution characteristic of its temperature The distribution of radiation'intensity versus photon-energy or wavelength that is emitted from a blackbody also known as a Planckian distribution Impulse applied to the material surface from vaporization caused'by x ray depOsition in the material The scattering of photons of gamma or x raysl by the orbital electrons of atoms In a collision between a photon and an electron some of the energy of the photon is transferred to the elec tron Another photon with less energy then moves in a new direction at an angle to the direction of motion of the primary photon A total er accumulated quantity of ionizing radiation or time integrated-dose rate The quantity of radiation received per unit time The kinetic energy of an electron based on its mass and the velocity attained through an acceleration produced by a potential difference of one volt abbreviated ev 0 1 ev 21 6 x10 12 ergs of energy A neutron with an energy level of 10 deV or more The energy or number of particles transferred across a given area perpendicular to the direc tion of flow also called timewinteg rated flux Typical units are cal cm2 for x rays n cmZ or for neutrons rads for gamma radia tion lOl DocId 32700119 Photoelectric Effect 9 Prompt Gamma i'R'ad Roentgen Source Temperature 3 Spailation Taps This page Unclassified Voiume iv The energy of number of particles transferred across a given area perpendicular to the direc tion of flow in unit time The process whereby a gamma or xsray photon with energy greater than the binding energy of an electron in an atom transfers all its energy to the electron which is consequently removed from the atom The photon is totally absorbed in the process The portion of the gamma environment that arises from fission and fusion in a nuclear anti missile warhead and from neutron absorption and inelastic scattering reactions with the mis- sile materials The prompt gamma radiation is emitted during the first few micro seconds after detonation A unit of absorbed dose One rad is equal to 100 ergs of absorbed energy per gram of absorbing material This unit cannot be used to describe a radiation field I A unit of exposure dose of gamma radiation or x-rayrs It is defined precisely as the quantity of gamma radiation or x-rays such that the associated corpuscular emission per 0 001293 gram of air produces in air ions carrying one electrostatic unit quantity of charge of either sign One roentgen of gamma radiation of'X-rays results in the absorption of roughly 87 ergs per gram of air Temperature refers to the kinetic energy of the particles composing a body in thermal equilib'- rium source temperature is the temperature of a blackbody whose emitted radiation most nearly matches an observed spectrum Material fracture caused by shock induced tensile stresses Unit of impulse or momentum equal to bar usec 102 This page Unclassified r is 199 SEER- Voiumeiv' - 1 1 1 - X Rays Electromagnetic radiation produced outside the atomic nucleus X rays have zero rest mass and zero charge Hot and cold xwrays are terms describing a portion of the spectrum of electrOmagnetic energy Cold soft low 5 1 energy and lowntemperature X rays Hialeah blackbody source temperatures up to about q 2 key Hot hard high energy and high- temperature x-rays indicate blackbody source temperatures above 2 Rev B 5 REFERENCES Preliminary Design Review Minuteman U Document No Autonetics North American Rockwell 7 September 1966 5RD BSD Exhibit U Document No 7550 61 63 1 1 000 Ballistic Systems Division Air Force Systems Command 4 February 196 6 U e 103 I J- 11 vmumelv INDEX VOLUNIE IV A Accidental attack 11 24 28 30 Airborne alert 7 23 Airborne Command Post AC P 23 Alert status 21 22 28 status impact on feasibility 722 Anti wa ruing system 474N 35 Anti-Sabina ri no Warfare 14 15 Ballistic Missile Ea rly W'arning System BMEVVS 474L 33u36 Bar 101 Beam hardening 98 Beta particles 93 Blackbody temperature 63 101 Blast damage 65 Blow-offinnm se 79 101 Blueusky attack 21 22 Booster vulnerability Minuteman 64 iBoost phase survival in - 99 -Vu1nerability - 43 -Warning 12 4 -Warning system 13 30 40 41 104 warning system 13 30 4 1 41 -warning system perIOrmance of 35 36 Bursti terval 15-17 47150 52 -points 48-50 52 Case to-iiner bond failure ' '77 vcrritical areas 78 damage 78 sure safe criterion 78 Characteristic of Soviet systen'is 24 25 Circular Probable Error CEP 25 Circumvention 95 97 Command and Control V de1aysin 14 38 39 improvements in 29 42 layout 38 -reaction time 20 Compton effect 98 101 Confidence in intelligence 51 Conservatism Soviet viewpoint 51 CONUS defense 22 Counter-force attac1 - effectiveness 28 29 -Inission 21 nature of 11 Warning of 9 Docldz32700119 UNCLASSIFIED 6 Volume False alarm rate 35 37 Decisign to launch 33 Fast neutron 101 Fluence 45 101 elays - 9 -'in command and control 12 38 Flux 101 -in decision process 39 Flyout 20 43 45 51 launch controlcenter 38 40 - in warnin stenas 35 36 def1n1t10n Of 32 -drawbacks to 54 Deployment- -feasibility of 23 wlimit on 60 -survivors of 54-5 map Wing I 7 48 Flyout strategy - 10 15 17 moratorium on 29 18 54 55 Depressed traiectorY 12 1nsensitivity to opponent's tactics 55 -thr eat 12 s willingness to employ 54 -time offlight 13 26Forward Scatter Over the attacks - 2-8 Horizon radar system lacredibility of 30 OTHF 440M 35 Dose 101 Fratricide avoidance OT 40 Dose rate 101 Free field environment 64 65 Dust as a pindown agent 43 3 Gamma ra rs 64 65 93 95 3 Early warning SYstexns 33 36 Gaps in early warning - coverage 37 cielays 35 -false alarm rates 35 Graduated response 22 -perf0rmance 35 Guidance and control 93 100 sum of Mexico 33 pulse EMF 94 9 6 97 f0rn1ati0n of 97 31 vulnerability 98 Hard x rays 95 Electron volt 101 Hardening - 50 61 64 Electronics weapons 95 97 98 9 effects on 96 -against gamma radiation 95 I Exhaust gas shield thickness 88 agalnst neutrons 97 aga1nst x rays 98 Hardness impact on plndown Fail safe 39 requirements 15 51 False alarm 11 105 UNCLASSIFIED Docld 32700119 Authority 792 2 UNCLASSIFIED ka- 33 Hg V Volume d a False alarm rate 35 37 Decisi'gn to launch 33 Fast neutron 101 7 Fluenc-e 45 101 Delays 9 command and control 12 38 Flux 101 -in decision process 39 Flyout - 20 43 455 51 _-in launch control Center 38 40 'in warning systems 35 36 -def1n1t10n Of 32 -drawbacl s to 54 Deployment n -feasibility of 23 l'1mit on 60 surv1vors of_ 54-57 nmapHWing I 48 Flyout strategy - 10 15 17 moratorium on 29 18 54 55 Depressed traiectorf - 12 insensitivity to opponent's 55 -th1 eat 12 S willingness to employ 54 -time of flight 13 26 27 34 41 Forward Scatter Oven-the _ D15gu 59d attacks- 28 Horizon radar system Ecredibility of 30 OTHF - 440M 36 Dose 101 Fratricide avoidance of 40 Dose rate 101 Free-field environment 64 65 Dust as a pindown agent 43 3 Gamma rays 64 65 93-95 Early warning systems 33 36 gaps in early warning - coverage 37 delays 111 35 -false alarm rates 35 Graduated response 22 -perforrnance 35 Guidance and control 93 100 Electromagnetic Gulf of Mexico 33 pulse EMF 94 9-6 97 f0rnlation of 97 i vulnerabilit 98 Hard x rays 95 5 Electron 101 Hardening 6U 61 64 Electronics weapons 95 97' 98 effects on 96 against gamma radiation 95 Exhaust gas shield thickness 88 agatnst neutrons 97 aga1nst x-rays 98 I Hardness impact on pindown Fail safe 39 requirements 15 51 'Falee alarm ll 105 -UNCLASSIFIED DocId 32700119 DECLASSIFIED Authority NM 792 29 a UNCLASSIFIED 5 iiardness o iAinutennan 15 17 20 45 51 of 'Minuteman guidance 1 and control 9 93 Hudson Bay 33 ICBM accuracy 9 Induced stress waves 66 Inertial measuring unit IMAU 96 Ionizing radiation 95 4 rLatchwup 95 ii L'aunch 32' 37 Launch control center 12 38 Launch coni r01 center delays in 39 40 Launch control center improvement of 40 41 61 Launch decision 3 Launc-h-on WaI-ning LOW 9 12 14 22 40-42 -credibi1ity of 14 18 2'1 42 Lethal radius SLBM warhead 15 18 30 43 Lethal volume 15 18 47 50 Limit on SNDV's 25 Lineruto grain bond Fm critical areas 80 damage 8O -fai1ure modes 79 80 5ure safe criterion 79 80 Looking Glass 23 Malnistrom Air Force Base 48 Minuteman 9 11 com1nand and control 9 38 42 f 1yout capability 63 guidance hardening 60 95-98 guidance weapon effects on 93 96 99 wharciening 60 61 89-91 hardness 15 43 49 53 63' 93 94 response 12 14 23 saved by flyout 18 19 55 58 -survival of 46 systern description 63 trajectories 46 47 50 vu1nerabi1ity see vulner Ldefinition of 42 ability ofMinuteman evasion Of 4 1 Minuteman motor case 67 69 76 feasibi1i cy of 23 4O irnpact of scenario on 22 back surface spell 68 69 76 -damage 69 Launch onwwarning policy 28 ldeSCL ipt'wn 67 Launch rate 54 -front surface spal 68 69 - -sure safe criteria 69 sequence 5 4 wall heating 68 69 w indow 4 6 Lethal effects persisiance of 43 National Command Lethal envn'onnient 43 45 Authority NCA 11 Lethal mechanis'm 96 -assembly of 12 22 39 1ecision process 24 106 DoeIdz32700119 DECLASSIFIED Authority NMQ 792 23 description of passing of authority reaction time 12 32 reluctanco to adopt LOW -'vulnerability to attack National Military Command Center NMCC 12 Neutrons 64 65 hardening against -impact on electronics Nozzle - damage wfailure modes wsure safe riteria Nuclear environment 43 - 0 Optimum pi ndown strategy Over the uho rizon radar OTHF Peak stresses Persistanoe of lethal effects Pindown -attacl allocation attack deficient 51 54 atta k guaranteed 15 43 duration 16 18 51 53 environment -evasion of 13 g eometry 47 RAD Retaliatory forces - may b - - na await-f 4 Human 4 UNCLASSIFIED vmumelV JAcopdsrigs suaiafailw I 32 Retaliatory options 22 Rideout zi 39 42 Roentgen 102 28 23 32 38 SAC Strategic Air Command 93 94 SAC bomber bases 28 97 SAC bomber bases number of 33 1 97 SAC bombers release of 39 79 84 SALT 9 24 99 84 Satellite-based early warning 79 system 12 36 4O 84 Scenarios 21 937 94 on LOW 22 Sea4Launehed Ballistic Missile 15 availability 17 18 deployment limit 20 60 6 35 36 inventory 17 18 Jaunch points 33 ope rations A 17 pr0duction rate Soviet 17 24 73 76 time of flight 12 13 23 25 41 44 Shielding 95 9-11 design considerations 98 19 55 jimpracticality 95 97 15 46 Silo hardening 28 55 57 17 18 Sneak attacks 21 46 54 Source temperature 102 19 30 Soviet systems see specific 56 57 stems 43 41 54 characteristics of 24 25 50 52 inventory' 24 2 5 submarine inventory 51 57 Soviet viewpoint 54 102 SpallCJ teria 63 22 Spallation 102 NW UNCLASSNHED DocId 32700119 DECLASSIFIED Authority NNQ 792 2 w 1 yoi'ume ACDA smss 55 9 1' 14 24 25 Taps 102 -imp_rovement's in 28 Temperature rise X-ray counte rforce effectiveness 29 deposition 70-72 0 Thermal radiation 93 - V improvernents in 28 Threat tube 46 1 C0unteriorce effectiveness 29 Time delays see delays 14 18 24 25 Time sensitive targets 19 22 depressed trajectory 2'8 32 33 capability 26 4O Trajectories Minuteman 46 range 40 -time of flight 26 yie Unauthorized attack 24 28 30 depressed trajectory Up nozzie exposure 87 88 capability 26 range 40 Strategic A1rCommand SAC 28 33 Vulnerability boost phase 43 49 Strategm alert 12 30 Vulnerability of Minutemai Strateglc warming 23 to blast 44 Submarine operations Soviet 51 to dust 44 Submarine availability to garnn a rays 44 93-9 Soviet 51 55 -to neutrons A 44 93 9 to x rays 44 97-100 Submarine standoff 13Vulnerability ofR to dust 43 Sure kill 1 15 45 Sure safe 15 18 20 45 63 Warning systems 11 Surprise attack 21 delays 33 pe rformance 33 Survivability 9 Weapon effects -- Qf manned bombers 60 1 om A 95 0f Minuteman 28 60 11 S 5 NCA 23 1n semiconductors 9 ff 0 on electronics 96 i of Presuient 23 Wing I 15 46 47 Wing VI 15 50 52 Tactics 10 Wing Genljjetry 15 4'6 flyout 15 17 18 54 5f pindown 15 19 7 108 UNCLASSIFIED 7 DECLASSIFIED A - 3 Add - Agni 11 4 win-43 wit-4-5 Authority Nigar-1 3 - 3 Volume lV X rays 14 65 87 94-97 103 x d position in 7 materials 66 79 81 83 85 7 uence 63 64 c '-hardening against 98 vu1nerability to 44 97 100 Y class submarine 19 57 58 Yield Soviet SLBM RV 15 17 44 109 - - This document is from the holdings of The National Security Archive Suite 701 Gelman Library The George Washington University 2130 H Street NW Washington D C 20037 Phone 202 994-7000 Fax 202 994-7005 nsarchiv@gwu edu