S SECFEI DEFENSE INTELLIGENCE AGENCY c WASHINGTON D C Z0301 c MiNUTES OF DIA SCIENTIFIC ADVISORY COMMITTEE t€ETIN6 21-22 MAY 1970 I U GENERAL A meeting of the DIA SAC was held on 21—22 May in Room 3E267in t1i Pentagon The meeting convened at 0900 hours on 21 May and adjourned at 1545 hours on 22 May II f U ATTENDEES A list of attendees is attached End 124 DI A SAC Secretari at representative was 1 The I III U AGENDA Copies of the tentative and actual agendas are attached Ends 2 and 3 IV SU iARY A The meeting proceeded as indicated on the “Actual Agenda” fEnd 3 During the course of the SAO Update briefing the Conmlttee requested of DIA a future briefing by DIAXX on the coverage probabilities and assurance for certain specific areas This would up—date informa tion of this sort presented to the OIA SAC Arms Limitation Panel In September 1969 B The second agenda item was a comprehensive revie of Chinese missile developments testing and nianufacturing leading to postulated characteristics and IOC for the Initial CPR ICBM The presentation stimulated the observation from Cojnnittee members that the SAC should devote some discussion to evaluating the impact of the Chinese missile progress on the SALT position that the US should take and Soviets too perhaps on the question of ABM At the conclusion of the briefing the SAC requested DIA to present at the next neeting a briefing covering 1 A revised estimate of the probable impact areas for CPR ICBM test flights 2 A discussion of launch azimuth indicators bXI 1 4fc 3 I ofL_J fl 4 c C Ibrlefillrindicatecf thatteam personnel will be sent to the site In July to investigate upgrading the capability of the radar The Coninittee expressed the belief that some U S technical personnel might be needed permanently on-site to Improve the RADINT performance S CR I bX1 j 4 c jmuch discussion centered around the questioned D Ont utility of the capability as being developed It was agreed that some benefit would accrue to US ECM design from use of the intelligence data obtained via this capability b13 1O usc 424 ireviewed the background for and the approach being EJ täkeii iii ri ati on to Ireques ted study of collection against ICBMieentry ± I stated that the study output being pursued is two—fold - - --- - — 1 Coniiients on_the uttlity and effectiveness--of -- Icollectiori systems •i -— 2 Alternative cost-level package proposals with associated assessed capabilities and risks To make the study more manageable with limited resources and suggested an inverse approach to the study je starting with I time I 10424 jbX collection systems and working backward toward the known intelligence re quirements to see which approaches appear rst effective Much discussion ensued It appeared that most felt that the study would have to be finally presented as a progression from identified intelligence requirements through to best proposed collection approaches and systems and that the study should therefore be structured according to this pattern discussed the issues ssQC14t withi_________ F ItbX3 b0C424 “Soviet Forces for Intercontinental Attackt1 andL zJ on Soviet home land defense forces tbX3 1O USC324 1 XJ 4 c G The real—time near-real-time collection presentation addressed the application of such a capability to the following crisis intelligence combat support event analysis intelligence production and strategic warning I Znphasized the need in connection with such a system to consider thoroughi what is to be done with the data as it is obtained Idiscusse t e DIA approach to evaluation of such a capability and indicated the formation of an ad hoc coninittee to prepare a preliminary report to DIADR by 1 Sept 70 and a final report by 1 Nov 70 - H The results fromI3 lOlD424 I verbal report to the Comittee on the “New Soviet ABM Efforts’ are reflected in the conclusions and Recommendations from the Executive Session fEnd 4 I A letter reporting on the findings of the Comittee was pre pared by the Chairman and forwarded to the Director DIA It is attached as Enclosure 5 CERIT FlED b13 1O USC 424 b 4 Enclosures a s Secretary DIA SAC SCCR 1 4 r’flT ‘JLL’t REVIEW PANEL ON DETERMINATION OF YIELDS OF FOREiGN UNDERGROUND NUCLEAR TESTS U A panel was convened by the Director Defense Intelligence Agency to address the question of how best to determine foreign underground nuclear test yields Panel membership is shown at Attachment 1 U its The Panel met three times In August and September 1985 and restricted study to the yield regime relevant I b11 t4fc u The I bX1 t 4 c Panel received an extensive series of briefings on 1X1 I 4 c jmethodologies and made the following observations lincreasingly mature Nt Over the past two decades I1b 114 c as a methodology for yield estimation Impressive advances have been made in both data acquisition and its interpretation but significant uncertainties still result in J bXIU 4 c Ibeing uncertain by about a “factor f tlT Results j bXl J4 c primarily of US and French origin show that a simple relationship exists between the yield of the explosion and the magnit de of bX1 14tc I at least for yields below curves can be developed for each about specific calibration IThus L distinct test site which allow yields to be estimated I0’11 i4f J bXt 14f I While these curves have been assigned essentially the same slope the absolute values are expected to differ from site to site and sometimes within a site chiefly because differences exist in the physical properties of the rock in which the explosions occur or through which the f bXl J4LC In order to simplify I pepgate—dee p under the test sites procedures a standard calibration curve was devised and is adjusted for each particular test site This adjustment is commonly known as the ttbX114 c I j h 1 14 Such a bias must be established for each test site including the Nevada Test Site NTS before yields can be reliably estimated jx1 14 I — S Wi Where yields are known e U S tests at NTS and Amchitka11 1ja bias value can be directly estimae For Soviet test sites ‘ where yields are not known all available sources of inormation should le considered in estimating the appropriate value of bias bx1u 41c I based on very Since that time a number of significant studies have been completed In the following subject areas ThL4 1 C LLcl1 o The availability of high quality digital data from which have made the f b 1 1 4 c jmore reliable X1 1 4fc o DetermInations of site—dependent attenuation of seismic body waves OJse of evid jjd information from the r sna -v — bXI J 4 f ’tIt In addition to focusing on surface disturbances as a potential complement bX1 1 4fc the Panel considered specific yield evidence derived from While it is not compelling evidence the collection community is encouraged to continue their efforts ‘llt As a result of examinlng It11 4 c panel found only one Instance j which had I bXI I4 2 I the the cratering shot crater phenomenology and explored the use of U The panel considered surface disturbances to complement fX1 I If there exists a depth of burial at which for a specific yield in a specific medium such as hard rock a distinct surface effect such as a crater will result if the detonation takes place above that burial depth and no crater will result at detonation depths below that depth then this so called Hcritical depth of burial” DOB The key may allow one to estimate yields in the yield regime of Interest question at issue is the magnitude of the difference In burial depth in hard rock which will either result in a crater or p p If the difference is small this surveillance method could complement the”4’ Z ’FIt Unfortunately the understanding of crater phenomenology is least in the vicinity of the postulated critical 008 for hard rock It is not certain that a sharp threshold exists if it does the scaled critical 008 may depend on yield local geology topography test configuration and other factors U S d rock data exists in e of i innrtant scald and the data between are inadequate to resolve the Issue trNr There exists some evidence that the concept of a critical 008 has validity It is noted that surface-disturbance observations can be grouped hito two classes throw-out craters and other surface disturbances including spall where all the disturbed material lies above the original ground plane but is not displaced laterally from its original position These two classes appear to be separated by a boundary in the 008 versus yield plane The boundary Is well defined by a line Cettain investigators have assumed a particular value for the relationship between yield and depth of burial in hard rock and from these assumptions have come to the conclusion that X1 14 c j at least for the test area fshould be reduced rather than increased However until additional data ate available 1 I4 c I hXI 14 C Imprecise as it is tNt It is possible that carefully controlled high—explosive experiments combined with calculational efforts could Improve the understanding of crateting phenomenology in the relevant yield rec’ dtstandittg can be quantified existing crat jcculd be used as an independent check of thel -fMt In the absence of such necessary understanding cratering data cannot be used to improve on or bound hXfl 14 c Research on cratering phenomenology and depth of burial should be encouraged and supported 3 • — — — •• — I tur- Since this techniqu s sensitivity requires the existence of a well defined critical DOB the Soviets could deny us additional information at Degelen Mountain or other test ateas by modest increases in the scaled burial Existing data from Degelen Mountain Test Area would still be useful depth however as a tough calibration of the entire Semlpalatinsk area INr It has been suggested In the intelligence community that a gap exists between Soviet nuclear test yields and the assessed yields of modern Soviet strategic warheads The Panel addressed this issue Tht 115 and th USSR ach stated In 1976 that it would adhete to the provisions t11t4 I P1t approximately the same time the test program ati I yields localized in the Jabruptly ceased CNt At this time the 55—17-1 and the 55—19—1 RVs which had been first flight tested in 1973—74 were being deployed These RVs were very similar in profile and size to modern RVs fSS—17-3 55—18—4 and 55-19-3 such that a common warhead or one with small modifications could have been used In all From the geometries and using modern U S weapon design technology the expected yields oralloy loaded would be a nominal I hXi 14fc1 4t I øX1 1 4 c The next—nrtion weapons technology might permit increasing the yield to as much as4 Ithe panel concludes tt th 4p0ai-ent yield gap between cessation of t’t higher yield testing at_‘ jind the deployments has no significance 3 NP- Regarding official community yield statements j b I lt c The panel notes with concern the absence of any centralized management of research and analysis of determination of foreign test yields from remote locations Over the years each involved Department and Agency has tended to find its niche While there appears to be reasonable interchange of information among these organizations no single entity takes responsibility for identifying new requirements for supporting new approaches for yield determination for prioritizing these new approaches for assuring that resources are properly applied to these new approaches and for insuring that the various resulting methodologies ate used to complement one another 4 ‘7f%%’ St k1Pfl1 ii S trNr In conclusion technologies available to us today do not provide the precision to determine in a legalistic manner wtiether or fbXl l4c Further without calibration explosions which are independently verified by the U S at the specific Soviet test sites it is not anticipated that one will ever be able to determine an equivalent high-explosive yield to better 4 4 than Iever with on—site instrumentation From a national security standpont however a precise determination of For hrd point targets an Soviet nuclear test yields is not critical improvement in RV accurac of only I Is equivalent to a to the present yields assessed factorM ‘ J Moreover for Soviet strateqic delivery vehicles have been derived OXL 14 c — Itt1 we rIr We should Indeed continue to improve 6X1M 4 c should devote increased resources I I we should centralize responsibility for research and analysis of foreign test yield determination but most important is the need to recognize our inability to the President monitor precisely the existing bX1M 4 c and agreement I should be so advised 5