Operation Ivy - Project 6.2, Report to the Scientific Director: Blast-Wave Mass-Motion Measurements (Deleted)

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Report to the Scientific Director Los Alamos Scientific Laboratory University of California This is an extract of WT-627, Operation IVY, Project 6.2. Approved for public release; distribution is unlimited. Extracted version prepared for

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Destroy this report when it is no longer needed. Do not return PLEASE NOTIFY THE DEFENSE NUCLEAR AGENCY, ATTN: STTI, WASHINGTON, DC 20305-1000, IF YOUR ADDRESS IS INCORRECT, IF YOU WISH IT DELETED FROM THE DISTRIBUTION LIST, OR IF THE ADDRESSEE IS NO LONGER EMPLOYED BY YOUR ORGANIZATION.

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\n outstanding conclusion of the experiment is the lowness of peak overpressures near the ;urface compared with the peak overpressures at altitudes up to 25,000 feet because Of the ?ffect of atmospheric fnhomogeneft iiagnostic tool for the determinat on of totalT at long ran es. 2 The mass-motion technique offers a useful REPORT DOCUMENTATION PAGE 2~ SECURITY CLASSIFICATION AUTHORITY 3 3iSTRlBUTION I AVAILABILITY OF XPORT . Approved for public release; distribution is unlimited. Scientific Laboratory Defense Atomic Support Agency 3a.NPME OF FUNOING I SPONSORING 8b OFFICE SYMBOL 9. PROCUREMENT INSTRUMENT IOENTlFlCATlON NUMBER PROGRAM PROJECT TASK ELEMENT NO. NO NO. Report to the Scientific Director, Blast-Wave Mass-Motion Measurements, Extracted Version 13~ TYPE OF REPORT 13b TIME COVERED 14 DATE OF REPORT (Vedr, Month, DeyJ 5. PAGE COUNT lti S~PPLEN~ENTARY NOTATION This report has had sensitive military information removed in order to rovide an unclassified version for unlimited distribution. The work was'performed by the. efense Nuclear Agency in support of the DOD Nuclear Test Personnel Review Program. 17 COSATI CODES 18 SUIIJECT TERMS (Conrmue on revcnr rf necessary ad idcntit) by bkk numkrJ FiELD GROUP SUB-GROUP Ivy, Project 6.2 King Burst Blast Waves Mike Burst Blast Measurements Instrumentation OPERATION IVY was instrumented for the mass-motion method of pressure measurement in a manner similar to that used on OPERATIONS BUSTER-JANGLE and TUMBLER-SNAPPER. Low-altitude pyrotechni nortar bursts and high-altitude gun bursts (on Mike only) labeled the air for photographic The methods of instrumentation are described, the method of data analysis is outlined and derived data on time of arrival, peak material velocity, peak shock velocity, and peak overlressure are presented in tabular and graphical form. Appendixes present meteorological and )allfstfc data and calculations. SECURITY CLASSIFICATION OF THIS PAGE

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Classified material has been removed in order to make the information available on an unclassified,open publication basis, to any interested parties. The effort to declassify this report has been accomplished specifically to support the Department of Defense Nuclear Test Personnel Review (NTPR) Program. The objective is to facilitate studies of the low levels of radiation received by some individuals during the atmospheric nuclear test program by making as much information as possible available to all interested parties. The material which has been deleted is either currently classified as Restricted Data or Formerly Restricted Data under the provisions of the Atomic Energy Act of 1954 (as amended), or is National Security Information, or has been determined to be critical military information which could reveal system or equipment vulnerabilitiesand is, therefore, not appropriate for open The Defense Nuclear Agency (DNA) believes that though all classified material has been deleted, the report accurately portrays the contents of the original. DNA also believes that the deleted material is of little or no significance to studies into the amounts, or types, of radiation received by any individualsduring the atmospheric nuclear test program.

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Operation Ivy was instrumented for the masr-motion method of pressure measurement in a manner similar to that used on Operations Buster-Jangle and Tumbler-Snapper. Low-altitude pyrotechntc mortar bursts and high-altitude Sun bursts (on Mike only) labeled the air for The methods of instrumentation are described; the method of data analysis is outlined; and derived data on time of arrival, peak material velocity, peak shock velocitp, and peak overpressure are presented in tabular and graphical form. Appendixes present meteorological and ballistic data and calculations. An outstanding conclusion of the experiment is the lowness of peak overpressures near the surface compared with the peak overpressures at altitudes up to 25,000 ft because of the effect ’of atmospheric inhomogeneity at long ranges. The mass-motion technique offers a useful diagnostic tool for the determination of total

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The ythor wishes to acknowledge the assistance of the following mea of the uss curtisa tn the installation and maintenance of the gun battery: . Timing system8 for activating the instrument stationa, as well aa -all photography and film processing, were provided by Edgerton, Germeshausen & Grier, Inc. The Naval Ordnance Plant, Pocatello, Idaho, performed an out&and@ service in the preparation and packaging for overseas shipment of the 3-h. SO-caliber guns. The Program Director, Program 6, Francis B. Porzel, was the originator of the massmotion method; his continued interest and atiaa are greatly appreciated. .

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1.1 Purpose of Experiment .... 1.2 Mass-motion Method and Prior Development CHAPTER 5 DATA ANALYSIS .... 6.3 Discussion and Interpretation of Result8 . 6.4 Precision of Measurements and Method Error8. CHAPTER 7 CONCLUSIONS AND RECOMMENDATIONS 7.5 Damage Sustained by Guns. ...l

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2.1 Location of Reef (620 Series) and Raft (621 Series) Stations 2.2 Reef Mortar Firing System ...... 2.4 Raft Radio Firing System .....a. 2.5 Location of Tone Transmitters ...... Gun Battery on Engebi ........ Location of Gun Stations, Shot Island, and Line of Gun Bursts (Plan new). Gun Firing Circuit ...... CHAPTER 5 DATA ANALYSIS 5.1 Reef Stations at Zero Time .... 6.2 Peak Material Velocity ..... 6.3 Peak Shock Velocity ...... CHAPTER 7 CONCLUSIONS AND RECOMMENDATIONS APPENDIX B BALUSTICS FOR GUN BURST 5a

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4.1 Camera Data, Mike and Mng Moptar Photography . 4.2 Camera Data, Mike Gun-burst Photography o . 6.2 Results, King Shot ....... ..... 35 APPENDEX A METEOROLOGICAL DATA A.3 Amblent Pressure and Density at Gun-burst Altitudes APPENDDK B BALLISTICS FOR GUN BURST 5a

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1.1 PURPOSE OF EXPERIMENT The desirability of obtaining tNe free-air pressure measurements has long been recognized, Project 6.2 instrumented Mike and King shots for this purpose. A true free-air pressure measurement is defined as one that is free from such perturbing factors as measuring instruments, structures, atrcraft, or reflection from the surface of the earth. A basic method for obtaining such a measurement involves labeling a parcel of air with visible particles and photographing their motion under the influence of the blast wave. Photographic analysis of the motion, together with basic’ hydrodynamic relations, determines the pressure value at that point. By placing the measurement points at various ranges from the nuclear detcnation, mateFurthermore, since the first motion of the labeled air indicates the time of arrival of the blast wave at that point, a time-of-arrival curve results from the measurements. Heretofore, this tyPe of pressure measurement has bqen limited to the region close to the ground, i.e., up to 1000 ft. Mike shot was instrumented from the surface to an altitude of 25,000 ft in an attempt to determine any asymmetry in the pressure field as the blast wave progressed through an increasingly rarlfied atmosphere. A long-range project, utilizing data obtained on this operation as well as data from previous operations, consists in the derivation of pressure-time curves from the mass-motion method. The large number of dots points, coupled with time and manpower llmttations, has precluded such analysis to date. 1.2 MASS-MOTION METHOD AND PBIOR DEVELOPMENT The broad underlying purpose of the mass-motion method of measuring hydrodynamic variables is treated elsewhere.’ The method, in general, consists in placing a small volume of visible smoke particles at a given position in space at a given time relative to a nuclear detonation; its subsequent motion, when struck by the blast wave, is recorded photographically. The analysis of the film record provides data cn the time of shock arrival and the displacement of the volume of labeled air as a function of time. This measurement of ma18 motion, together with meteorological data, may then be converted into a value of overpressure ia the Several methods of labeling the air for photographfc recording hqve been investigated during previous operations. The two methods’ utilfaed by Operation Buster-Jangle were (1) a smoke plume produced by a JATO unit and (2) an “aerial salute,” a commercial pyrotechnic producing a smoke puff in the air several hundred feet above the ground. In addftion to these

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mothoda, Operation Tumbler-Snapper included a feasibility teat of antiaircraft gear for producing smqka puffa at higher altitudes.* Experience on these operation8 showed that the pyrotechnic smoh puff suited the low4titude measurement and that the adaircraft ahdl, of the

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m order to extend the low-altitude stations t0 the high-pressure region on Mike shot, the four stations closest to ground zero were located on the reef. For reasons of convenience and to cause least interference with other projects, the mortar line extended out the seaward reef northeast of Elugelab. Figure 2.1 shows the location of these stations in relation to ground zero. Beef Stations 620.01 to 620.04 were at ranges of 4420, 5900, 8250, and 11,490 It from zero; the average altitude of the mortar bursts was 350 ft. Each station consisted of a steel pipe embciided in a concrete block which, in turn, was embedded-in the reei; the steel pipe extended 8 it above high-tide level and was provided with two 6-in.-square steel platforms 2 ft from the top. Holmes and Narver (H&N) drawing No. 6128-Q-3 gives the construction details. Submarine cable was laid to each station from the . nearest EG&G timing station on the Bogon-Elugelab complex. Timing relays and battery power supply were located in the timing station, the seaward end of the cable was connected to the mortar at each station, and the -5 set signal transmitte$to the station fired the mortar. Figure 2.2 illustrates the firing system for the reef stations. To complete the preparation of the StatiOn.fOr firing necessitated mounting a pressed cardboard mortar on the piafform and securing it to the steel pipe, inserting the mortar charge, and connecting the firing squib to the timing cable. The charge and mortar were weatherproofed by wrapping with aluminum foil which effectively kept the stations watertight; the location of instruments at 6 ft above high-tide level minimized dampening due to spray. All units functioned perfectly during several dry runs and at shot time. Each station could be serviced in less than 5 min, and the chain of four were usually covered in about an hour, utilising a DUEW for transportation across the reef. To extend the low-altitude instrumentation out to the low-pressure region, five raft stations plus a station on Mack were installed. These were Stations 621.01 to 621.06, located at ranges of 15,900, 21,400, 30,130, 37,200, 47,710, and 68,000 ft from zero for Mike shot (Fig. 2.1). A seventh stat@ was Iocated on Parry at a range of 114,970 ft. For Elng shot, six rafts, extending from the north tip of Runit westward into the lagoon, were used. The basic raft station was a kO- by 12-ft planked structure supported on ezch corner by two SO-gal drums. In the center of the raft was mounted a 4-ft-high platform designed to accommodate the mortar, power supply, and radio timing equipment. The raft construction details are given by H&N drawing No. 6141-Q-3. Figure 2.3 is an over-ail view of a typical raft. Since it was impractical to run timing cables to each raft in the lagoon, a radio timing

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Fig. 2.1-Location of reef (620 series) snd raft (621 series) stationS. ELECTRIC SQUIB AN0 MORTAR CHARGE Fig. 2.2-Reef mortar firing system.

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system was developed by EC&G for installations such as this. Each raft was equipped witha receiver,uariabkt delay timer, and mechanical clock for activating the unit at about 1 hr before shot time. Figure 2.4 is a schematic drawing of the radio firing system, and Fig. 2.5 shows the locatfon of the tone transmitters with respect to the rafts; The delay timer was necessary to provide a suitable delay between receipt of the signal and the firing of the mortar. Since these stations extended to a considerable range, the smoke puff would have been dispersed at shock arrival if a delay network had not been incorporated in the firing system. The detaiied @reparation of the raft stations for the dry run and for the shot !a of interest. * The mountingplate which held the mortar, radto receiver, and storage battery weighed approximately 60 lb and was extremely unwieldy, especially on such an unstable platform as a raft moored in the lagoon. It was believed that the installation would be simplified by mooring the raft after the radio and mortar had been mounted on the raft. An LCT was used for transporting the rafts to their mooring buoys; a crane, for depositing the raft alongside the buoy; and an LCM, for the actual mooring operation. Formidable as it sounds, the experience achieved on the mooring of the rafts for the dry run allowed the final instailatisii of six stations to be made in less than 5 hr after loading the rafts aboard the LCT at Parry. The B&N personnel handling the crane and boats became so proficient that a maximum of IO min at each station was required to place the raft in the water, tow tt to its buoy, moor it, load the mortar, make the final electrical connections, and start for the next station. Weather protection for the mortar and charge was similar to that used on the reef stations -aluminum foil wrapping with a rupturable foil cover over the mortar. The timing units were encased in steel boxes with gasketed lids. Each mortar charge was aluminum-wrapped to minimize chances of detonation of the charge during its time of flight since several of the stations were at ranges such that the charge would be in its upward trajectory during the period of high thermal-radiation rates from the nuclear detonation.

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That portion of the mass-motion experiment designed to measure hydrodynamic variables at high altitudes above the surface of the earth required the installation of a battery of 10 antiaircraft Suns on Engebt. Twelve dusl-purpose S-in. IO-caliber guns were obtained from the Naval Grdnance Plant (NOP), Pocatello, Idaho; 10 were installed on Engebi, and two complete units were retained on , Parry as spares or for spare parts. Figure 3.1 1s a general view of the weapon. Detailed information on the Mark 22 mount may be found inreference 1. The units were completely disassembled, cleaned, reassembled, and prepared for overseaa shipment by the NOP, Pocatello. Each unit was shipped is two costalners, one crate containing an assembled mount. aad slide and one containing the barrel-and-breech assembly. The preparation accomplished by the NOP greatly facilitated field installation. The mount was instslled on a concrete base, . plate, and the insertion of the bsrrei rquired about 10 min. The concrete base plate, constructed by H&N, is shown on their drawing No. 5129-J-LA view of the lo-gun battery on Engebi is shown in Fig. -3.2. Figure 3.3 shows the relation between the Sun ststlons, shot island, and the line d gun bursts (projected in plan). The guns were quipped with an electrical firing system. Firisg wss accomplished on an EG&Gtiming signal by plscing an EG&Grelay in series with the battery power …