The following intelligence organizations
The Central Intelligence Agency ond the infe!DnjSrt^'of Siale, Defense, ihe" NSA. ond
Mr. Huntingtonheldon, for Deputy Director Mr.ughes, The Director of Irire
Concurring.-
Stole
Moj. Gen. Robert Taylor, 3d, for Director)'Defenser. Louis W. To/dello. for Director of iheMr. Howard C. Brown,Assistant General'*
Mr, Wllliomregar. for Assistant Director, Fcrfe^TjflurcauT subject being outside of his
Pag*
THE
FOREWORD
CONCLUSIONS
DISCUSSION
L CURRENT SOVIET NUCLEAR WEAPONS
Applicablerogram! Other Than ABM. 4
Applicable Io ABM Program! 5
TABLEOVIET HICH ALTITUDE TESTS 0
II. IMPACTHRESHOLD TEST BAN TREATY ON SOVIET
MILITARY PROCRAMS T
A. Limitations on Nuclear Testing 7
B Impact on Military Programs Other Than %
C Impact on ABM 9
HI. US DETECTION CAPABILITIES 9
Capabilities of the10
of Intelligence Source*
a11
IV. THE POSSIBILITY OF SOVIET COVERTU
I
robeotcret
given seismic event of magnitude greater5 was causeduclear detonation andreaty violation.
conclusions
believe that for most of the Soviet military developmentwhich we can foresee over the next fewhresholdTreaty would impose no greater restrictions than those alreadyby the Partial Test Ban. However, the relationship betweenof underground explosions and the resulting seismic readingsat best, and can be greatly altered by decoupling.might therefore still testide range of yields,how far they were willing to risk violating the treaty and tocost and effort of decoupling. Practically speaking, wethey could develop weapons yieldingfj
by scaling up from lower yield tests which wouldair chance of not producing seismic readings They might con-ceivably developweapons withy expensive decoupling methods. (Paras.
respect to ABM weapons, we think there is about anthat the Soviets have already]
rexoatmospheric ABM warhead yielding)
If they have not already donehreshold Treaty would not. in our view, makeevelopment impossible, as we believe existing Soviet weapon technology would support it either without further testing, or with tests that wouldeasonable chance of not exceeding the threshold. (Paras.0
believehreshold Treaty would imposebeyond those of the Partial Test Ban, only forwhich might need new warheads yielding^
If the development of such weaponsufficiently high priority the Soviets might conduct tests virtually certain to violate the treaty, in the belief that the violation could not be proved against them. As few as one or two suchear could be of significant aid to their military programs. (Paras.0
i;
3
US Atomic Energy Detection System (AEDS) woulddetect all seismic events in the USSRagnitude
5 or greater. Perhaps with help ^ni^BHHH) it could probably discriminate between explosions andt) occurring in most parts of the USSR, but there would stillewearspecially in the Kamchatka-Kuriles area, which could not be so identified. Such events would representtreaty violations, but it would be extremely unlikely thatcould with certainty either confirm or denyuclear event had in fact occurred. (Paras.
a seismic event5 was identified as an explosion,almost certainly be nuclear in origin. Thus this evidence,with what might be available from intelligence sources,be sufficient, exceptew cases, to determine to theof the US government whether or not the explosion wasin origin. Evidence sufficient toorld forum thatwas nuclear could almost certainly be derived onlyinspection, which is not permitted by the Thresholdconsideration. )
DISCUSSION
I, CURRENT SOVIET NUCLEAR WEAPONS TECHNOLOGY
put decade of increasingly sophisticated Soviet testing of nuclearand weapons lias included3 series, two series of intensivend two years of testing underground since the Partial Testwas signed inn evaluation of the effects of aBan Treatv on Soviet military programs must starteview ofnuclear technology developed through these tests and its relation toprograms.
A. Technology Applicable to Progroms Other Than ASM
Development. The Sovietsamily of thermonuclearresponsive to the present needs of their strategic attack andforces. Soviet Long Range Aviation and the Rocket Forces havenumber of older TN weapons in the low megaton range based on thethe tests conductedS and earlier. Weapons based onest series probably began to enter stockpilend are nowin significant quantities, and will continue to be produced in orderolder weapons still in the strategic attack forces stockpile. Thesegenerally represent significant improvements over the entireand probably include some high yield (over ten MT) TN weapons
for delivery by both aircraft and mussies. A
luitablc fors estimated to be now availableesult ot the
ests.
Soviets had5ariety of relatively largeweapons inUJPJranSe-are probably soil inin large numbers for tactical missile and rocket forces, for tactical aviation.
for general purpose uses by the Soviet navy, and for SAM forces. As a
ofest! the Soviets were able to develop fission weapons in
^PJ Most of the never
iission weapons entering the Soviet stockpile in the last few years arc probably these improved low-yield weapons.
to the Partial Test Ban Treaty the Soviets had largely fulfilledrequirements for multimegaton TN weapons and for fission weapons.irillequirement for TN warheadi in the submegatonor thehis requirement can be fulfilled underTest Ban. and probably would be fulfilled before the Sovietsa Threshold Treaty Under the Partial Test Ban. the Soviets haveyielding upT. Some of the tests yielding aroundT and higher
were probablv directed toward development of TN weapons Several tests yieldingTor less have been detected, especially during the past year, thru could have been oriented toward development of either fusion or TN weapons. Some weapons based on (he underground tests of the last two years will probablv start entering stockpile next year, and will be available for systems bemgover ihe next several yean.
ffects Testing Our analysis of Soviet tests provides very littleon Soviet programs to enhance the kilt potential of nuclear weapons, or on the slate of Soviet knowledge of the various kill effects of nuclear explosions. Most of the thermonuclear tests were held at Novaya Zemlya, where the Sovietsprobably able to instrument only for the basic diagnostic informationfor development of TN weapons. Most of the Soviet fission devicestested at Semipalatinsk:know lirtle about the methods of testing there or the kinds of effects instrumentation employed.
evidence does indicate, however, that the Soviets havetests of the effects of nuclear bursts on military equipment andWe have also detected one HE explosion which may. amonghave been partrogram designed to test hardness of missilewe cannot say how much the Soviets may hove learned aboutfrom their tests, they have clearly had ample opportunity to discoverimportant nuclear effects which we have discovered.
of Soviet publications and classified manuals shows thai theacquired effects data of sufficient scope and quality on air. surface,and underground bursts to be adequate for planning and executingoperations. Unclassified articles show that they are aware of theradiation effects on electronic equipmentlthough we haveof the extent to which (hey may nave explored these effects, weevidence that they are aware of the vulnerability of US missileto them. The Soviets have also shown that they understand thepulse (EMP) phenomena produced by nuclear explosions, andhaveumber of low-yield surface tests to measure theon military systems and communications equipment. Although theprobably aware of the EMP vulnerability of ICBMt and silos, it isthey have conducted tests of the surface EMP effects of high yield weapons.
S. Considering the foregoing, we think the primary effect of the present Partial Test Ban on Soviet weapons programs has been to prevent complete systems testing and effects testing in the atmosphere or space. Nevertheless, the Soviets can obtain some significant data on these effects by simulating atmospheric and space environments in underground tests.
B. Technology Applicoble to ABM Programs
igh-Altitudeuringeries, the Sovietsumber of high altitude nuclear tests, primarily at Sary Shagan. (See
OVIET HIGH ALTITUDE TESTS
Joeor Tt)T
[08
1
ct iBfli
OctNov.
ArraoxiM.ie "ELD
l
ArrDoxaiATC
AbTRVM (KM)
8
KY Vertical Shot
KT-SS Shot (Multiple Miuilel
testsoviet interest in assessing the capability of an ABM svslem to discriminate and track mo or more targets approaching successively on nearly identical trajectories, bothadar blackout environment andormal atmosphere.2 events appear to have been conducted for the primary purpose of studying the effects on radar systems of blackouts created by high yield precursor bursts or by detonation of the interceptor's own ABM warheads. Data relating to certain long range effects, such as EMP and TREE, may also have been collected. It is unlikely, however, that the tests involved devices which had enhanced radiation output (ie,r that the Soviets were testing for the vulnerability of re-entry vehicles (RVs) to shock produced by surface absorption of loways.'
h ciiierf Certain Sudcar Weapons. Another portion ofest scries involved the detonationroup of TN weapons in5 MT range. These weapons showed certain characteristics suggesting that theyew Soviet weapons design. One recent attempt toheoretical model exhibiting these characteristics ledesign that could produce anay output. We think it likely that the Soviets would realize the importance ofay effects for eioatmospheric ABM weapons and could adaptesign accordingly.uch it the case, the Sonets then couldeapon that would emit X- _
i.Sfe)
towoutput Is one ofcilo-ekctror, volts iy
s* -
S^ET
o.toatmosphertc role in such defenses is the Caloshalosh-tvpo. Givendifficulties of identifying lethal warheadsloud ofoutside the atmosphere, it is desirable that an exoatmosphericemploy weapons with asill radius as feasible. This in turna nuclear warhead with improved kill capabilities, one way ofmight be throughays. One of the group of weapons describedpreceding paragraph appears highly suitable for use with the Galoshhave no evidence whatsoever that this or any other of the group ofnuclear weapons is the Galosh warhead, nor indeed can we be sure| HLaaaaaaaaaaHLHHH Neverthe-
less, the apparent deployment of an expensive ABM system employing eso-atmospheric interceptors argues that the Sovietsarheadarge kill radius, whatever mechanism may be used to achieve it.
he considerations in the preceding paragraphs lead us to believe thatare about even that the Soviets have developed an exoatmospheriethink that
they did notomplete systemt is of course desirable to test ABM warheads in their actual environment, but it is possible byfrom laboratory and underground test data to calculate the effects of specific warheads on various objects at various altitudes.
IMPACTHRESHOLD TEST BAN PROGRAMS
TREATY ON SOVIET MILITARY
Limitations on Nuclear Testing
Degicc of Risk Accepted. Because of variations in geological structure and in the propagation paths of seismic signals, nuclear explosions of the same yield may produce quite different seismic readings. Experimental evidence based on US tests and measurements indicates that the seismic magnitudeuclear (est of known yield andiven medium may vary by upnits on the Cutcnborg-nichter scale. Asercent of the cases fall above andercent below the avengehot intended toeading5 on that scale would0 percent chance of exceeding thatountry desiringercent assurance of not exceeding5 limit would be limited to tests of about one-half the yield it might test with onlyercent assurance.
Testing Medium. Most detected Soviet underground tests havece in uranitc.
I We believe that the Soviets have had little experience in testing underground in dry alluvium at yields above the low kiloton range. The USSR probably has alluvial deposits of sufficient depth, but we do not know whether the deposits are dry toepth as would permit resting BJj
ecoupling. It is possible that the Soviets would resort toin which the nuclear explosion takes placearge cavern,the seismic disturbance. Decoupling at lower yields appearsto decouple larger yields so that they can be tested within magnitudeincreasingly expensive and difficult. It has been estimated thatgiven seismic threshold one might test withevice with ato as much asimes greater than could be tested withoutBut thisighly theoretical and obviously very uncertainu practical matter, it seems to us likely on the basis of presentseismic effects from an explosion on the order ofcould,
most of (lie time, be degraded through decoupling to5 reading,ery large and costly cavity would be required.
he Soviets could probably scale up from the devices they testedwith reasonable confidence, weapons having yields four or five timesas the test devices. Thus, we think that, providing theyhance of exceeding the threshold, the Sovietsonceivably they might develop
weapons with yieldsutilizing expensive decoupling
methods.
Impact on Military Programs Other Than ABM
IS. It follows from what has been said abovehreshold Treaty would not scriouilv hamper Soviet development of small yield tactical weapons, low yield testing for special effects (enhanced or suppressed radiation for tacticalr acquisition of data on the vulnerability of components. Underreaty, though with some risk of violating ;f. the Soviets could alio probably develop new or follow-on TN warheads with yields JB
for their small-sllo missile systems, as weH as for new naval musile systems.believe :lut for the tests needed to develop an entirely new warhead with- Soviets would be. forced either to resort to expen-
sive decoupling, or. more likely, toreater thanercent chanceest would5 seismic reading. Full-scale tests of high yieldor of silo liardness against nuclear weapons cannot be conducted under either the Threshold Treotv or the Partial Test Ban.
new warheads of such yields which are hardened against US ABM weapons, or which can be used in their own ABM programs, or both. Apart fromthese possible requirements, we believe that the Soviets do not need to conduct such tests .is would carry high risk of violating the Threshold Treatv.ests enabled them to develop multimcgaton weapons with acceptable yield-to-weight ratios for Long Range Air Forces and Strategic Rocket Forces, and to test effects of these weaponsegree compatible with military requirements.
Impact on ABM Progroms
As stated above, we believe there it about an even chaace that the Soviets have already developedABM
If they have not already donehreshold Treaty would not, in our
makeevelopment impossible, as we believe existing Soviet weapon technology would support it, either without further testing or with tests that wouldeasonable chance of not exceeding the threshold. The Soviets coulday lethality data applying toarhead from underground testing without violating the Treaty. We believe also that inests the Soviets acquired enough data on radar blackout effects to permit them to develop and deploy this weapon system. Although the Soviets would almost certainlyequirementull-yield eioalmosphertc teat of the system and for tests to acquire additional blackout data, this is already prohibited under the Partial Test Ban.
believe the Soviets have not developed an ABM warhead_yijth_M
T!'c> mighteed for
such wjiBBWtiiiiiWBMB
In this event, we believehreshold Treaty would notimit-ing factor as long as the prospective warheads were in the submegaton range. For the developmentew ABM warhead of this type in the multimegaton range the Threshold Treaty wouldignificant limitation over the present treaty.
S DETECTION CAPABILITIES
ability of the US tohreshold Treaty and to detectinvolves establishmenteismic event has taken place and ismagnitude, identification of such an event as natural or explosive inIdentification of an underground explosion as nuclear orifferent, but related, problem is that oforld forum
TOf.
igint may alsoseful back-up look but it is not of itself sufficient to prove or to disprove the occurrenceuclear test. Since the Partial Test Ban has been in effect, one or more Sigint indicators, such as Sight activity, weather reporting, or Soviet detection system activity, have been associatedarge percentage of the Soviet underground tests. There have been some cases when no Sigint indicators were acquired. There have been more cases in which indicators were acquired but no tests were detected; many of these indicators may have been related to tests which were postponed or cancelled or were below our threshold of detection. Thev mav have been drv runs.
iolation
THE POSSIBILITY OF SOVIET COVERT VIOLATION
e have estimated above that the Soviets can meet most of theirrequirements for weapons development withouthreshold Treaty. If they foresaw testing requirements for military programs that would require consistent violation, they probably would not sigo the treaty in the first
'We have assumed in tho Foreword an agreed interna tonal procedure for establishingettmlc diiruibnnce
)
12
JRRET
place. We also believe they would no! secede to the treaty unless they thought It would be relatively advantageous to them, or at least not disadvantageous. Once they had enteredreaty, the Soviets probably would feel that the advantage to be gained from frequent violation would not be worth the political damage to their international position, providing these violations were proved against them.
Original document.
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