Operation Ivy - Pacific Proving Grounds - Report to the Scientific Director, Project 3.7 - Photographic Crater Survey

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This document consists of 23 pages Report to the Scientific Director PHOTOGRAPHIC CRATER SURVEY Lookout Mountin Laboratory LOS Angeles, California

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The primary objective of Project 3.7 was to determine the exact ground-zero location of Mike device after detonation had occurred and to obtain aerial photographs showing all possible aspects of the crater. k order to accomplish these objectives vertical aerial still photographs were obtained from an R13-50 reconnaissance aircraft at the earliest possible time consistent with radiation safety following detonation. These photographs were then printed at the U. S. Air Force Aeronautical Chart and Information Center in St. Louis, Mo., and further assembled into a precisely controlled mosaic form in order to provide at least two methods for accurately determining ground zero therefrom.

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Reproduction and Photogrammet ry . Objectives of Project 3.7 .... Photographic Mosaic of Mike Site Prior to Detonation Photographic Mosaic of Mike Site After Detonation . Map Showing Mike Site Prior to Detonation . . Profile of Mike Crater, North-South Looking West , Profile of Mike Crater, East-West Looking North .

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PHOTOGRAPHIC CRATER SURVEY 1 RE PORT OF OPE RATIONSI k 1.1 Assignment of Project ~, Preliminary discussions leading to assignment of Project 3.7 to Task Unit 9 (Lookout Mountain Laboratory) were held between members of the Air Research and Development Corn-;! mand (ARDC ) and Task Unit 9 on 7 May 1952 at ARDC Headquarters in Baltimore, Md. At this time the objectives of the project were submitted to Task Unit 9 so that planning could be Formal assignment was made by letter from Headquarters, ARDC, Subject: “Photographic Crater Survey, Project 3.7, Operation Ivy, ” dated 30 June 1952. (a) Objectives. As outlined in the original memorandum of requirements and illustrated ~ in Fig. 1, the objective of Project 3.7 was to obtain aerial photographs from which could be determined (1) the location of ground zero following detonation and (2) information as to the di- !,, ameter, depth, and lip contours of the crater. As an additional objective a requirement for an aerial mosaic of Bikini Atoll was subse - quently initiated by the Commander, Task Group 132.1. (b) Pe~sonnel. Personnel to accomplish Project 3.7 was provided by Task Unit 9, and duties incident to the accomplishment of the project were assigned as additional duties. This arrangement precluded any necessity for providing a separate group of personnel detailed to this project alone. Early in the planning phase it was realized that some technical advice regarding photogrammetry would possibly be needed. Therefore the services of a qualified technician in this field were requested of the U. S. Air Force Aeronautical Chart and Information Center (ACIC). This request was granted, and one technician was detailed from that organization for service with Task Unit 9 for the period 8 October to 24 November 1952. The advisability of having such technical advice available during the operational phase was amply borne out. Photographs made on the project were developed in the field and immediately checked by the technical advisor to ensure (1) adequate coverage of the target, (2) suitable photogrammet ric quality, and (3) sufficient photographs to accomplish the project. the photography for Project 3.7, was requested and received from the U. S. Air Force Strategic This aircraft arrived on 18 october 1952 and was based at Kwajalein. The crew proceeded tO accomplish the assigned mission as weather permitted and had accomplished approximately ?5 per cent of the necessary preliminary photography when the aircraft was destroyed in a fire

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Fig. 1 –Objectives of Project 3.7. Fig. 2—RB-50 photographic aircraft on fire. site as it a tion of the

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following a landtig at Eniwetok on 23 October 1952. The film for a complete mosaic of Eniwe - tok Atoll, as well as prelimtiary blast-area photography, was destroyed in this accident. Figure 2 shows this aircraft on fire. Request was made for an immediate replacement for this aircraft. The replacement ar - rived on 1 November 1952 but, owing to mechanical cliff iculty, was unable to participate in the air photographic mission on Mike day. Several missions were flown to the crater area as weather permitted, and all photography necessary to Project 3.7 was obtained prior to King shot. AI1 film was developed in the Forward Area and evaluated by the techni=al advisor together with other personnel concerned. 1.3 Reproduction and Photogrammetry Upon return of the Task Unit to the Zone of the Interior, the negatives were couriered to the ACIC at St. Louis, Mo., where the printing and photogrammetry necessary to complete the project were accomplished. Reproduction at the ACIC consisted of the following: 1. A photographic mosaic of Eniwetok Atoll made to a scale of 1 to 25,000. This mosaic consisted of five separate sheets, one of which depicted the terrain features of Mike site after detonation. This sheet was used for plotting ground zero and Mike crater characteristics. Figures 3 and 4 are photographic mosaics of Mike site before and after detonation. 2. Lithographic line charts of Eniwetok Atoll made to a scale of 1 to 25,000, depicting Mike site as it appeared after detonation. Figures 5 and 6 are pre - and postdetonation charts of 3. Photographic mosaics and lithographic line charts of Bikini Atoll at a scale of 1 to 25,000, as required by the Commander, Task Group 132.1. 4. A large-scale aerial mosaic of Eniwetok Island proper, as required by the Commander, Task Group 132.1, for use by Task Group 132.2, Eniwetok. 5. Profile drawings of the Mike crater looking east to west and looking south to north. These were prepared from an uncontrolled field sketch prepared by the engineering firm of Holmes and Narver from soundings made of the Mike crater. Figure ‘7 is a graphic presentation of the Mike crater, and Figs. 8 and 9 are charts of the profile determined from a contour sketch made from sounding information. It should be emphasized here that all material prepared for Project 3.7 by the ACIC was to specifications which stated that the accuracy would be the best possible consistent with control data available and within the time limits set for completion of such reproduction. Therefore in many cases the accuracy was not of the degree desired or possible because of the limited time for completion and because of the unprecise nature of control data available. In the case of mo - saics and charts of Biktni, no control data of any nature were available at the time of reproduc - tion; hence this material is entirely uncontrolled. Rigid security controls were established for handling all film and classified material connected with the project. Film of the postblast crater area was classified as Top Secret Re - stricted Data and subsequently downgraded to Secret Restricted Data by order of the Cornmander, Joint Task Force 132. All personnel handling this material, both within Task Unit 9 and at the AC IC, were properly cleared to handle material of this classification. Funds in an amount totaling $35,000 were obtained from the ARDC, U. S. Air Force, to accomplish the project. After reviewing the actual expenditures at partial completion stages Of

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Fig. 3 —Photographic mosaic of Mike site prior to detonation (not to scale).

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Fig. 5 —Map showing Mike site prior to detonation (not to scale).

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Fig. 6—Map showing Mike site after detonation (not to scale). Values in large numerals were obtained from postblast soundings.

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the project, ~1 funds =ceeding $ 10)OOO were returned as surplus to the needs of the project. Funding for project 3.7 WaS projected on the basis of prevailing costs for anticipated reproduction to be done at the ACIC. Subsequent to initial planning and budgeting, a readjustment of tnternal funds of ACIC m~e it unnecessary to transfer mY funds to that installation. Therefore all funds for this purpose were saved. Further costs were anticipated ~ Procurement of preckicm aerial mapping equipment. However, suitible equipment wss located with~ the Air Force at mmey Air Force Base, ~efio Rico, and flown to the operational site in the photographic aircraft~therefore funds anticipated for this material were saved. AS a consequence of these savings practically all the funds allocated for Project 3.7 were returned- Of the $35,000 obligated, Only$5,500was eventually expended. The first objective of Project 3.7, to obtain ground-zero location after detonation, was fully accomplished through aerial photographs obtained on the project. Information for plotting ground zero was supplied in two forms: 1. The Overlay Method: This method, reportedly the most accurate, uttlizes the overlay system. A vertical mosaic of the area prior to detonation is prepared and prtnted to an accu - rate scale. Photographs of the postblast area are then prepared and printed by rectification to the exact scale of the preblast mosaic. The preblast mosaic is then superimposed on the postblast mosaic, and zero point is punched through. 2. Triangulation Method: In this system pre- and postblast mosaics of the area surrounding zero point are prepared. Then, utilizing bench marks so worked as to be visible in the aerial photographs, ground zero is plotted by back triangulation. The second objective of the project was effective in a general way only. Repeated mechanical difficulties with the survey aircraft, together with adverse weather conditions, precluded early photography of the crater area. Since the crater area was largely submerged in water, few of its physical aspects were apparent in aerial photographs. A general impression as to diameter could be obtained by inspection of photographs depicting water area newly created where land masses had once stood. The submarine topography of the crater appears to be generally as depicted tn Figs. 8 NO major problems were encountered in the conduct of Project 3.7 (other than the unavoidable 10SS of the project aircraft), and it is recommended that any future projects of this nature be conducted in the same manner. Operationally no additional personnel was required since the project was accomplished as an additional duty of Task Unit 9. The importance of field development of aeri~ negatives in order that results and coverage Can be quickly ascertained cannot be emphasized too strongly. It is further recommended that the services of a qualified technical advisor such as used on Project 3.7 be made available dur~g the entire Forward Area phase of such projects. Much time can be saved thereby through proper flight-line planning and positive checks as to adequate coverage following each photographic flight. It is recommended that the services of the ACIC, U. S. Air Force, be utilized for any photogrammetry and/or charting services required in connection with any future projects of this nature. This f~ility has adequate skilled personnel ad equipment to provide material with the highest degree of accuracy desired consistent with ally imposed time limitations and

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engineering control supplied. Additionally this installation has established a separate section staffed with properly cleared and qualified personnel to accomplish projects of this nature. Since these procedures have been established, it is believed that such facilities should continue to be utilized when a need extsts. Some confusion existed as to the primary and secondary requirements for Project 3.7. It was first established that the primary requirement was to determine ground zero and the secondary requirement was to determine certain crater dimensions. These requirements were delineated in the formal letter of assignment. Subsequent correspondence from the Armed Forces Special Weapons Project, after the conclusion of Project 3.7, stated that the objective was to obtain crater dimensions such as diameter and lip contours within two days after detonation. This letter made no mention of any requirement for determining ground zero. It is recommended that on future projects of this nature the requirements for accomplishment of the entire project be delineated in such a precise and clearly defined manner that no possibility of any equivocal interpretation will exist.

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of this nature. es should continue id zero and the ce from the Armed hat the objective manner that no Chief of Engineers, D/A, Military Construction Division, Protective Construction Branch, Engineering Division, Structural Branch The Quartermaster General, CBR, Liaison Office, Research and Development Division, Chief of Transportation, Military Planning and Intelligence Division, D/A, Chief, Army Field Forces, Ft. Monroe, Va. Army Field Forces Board #2, Ft. Knox, Ky. Army Field Forces Board #4, Ft. Bliss. Tex. Commanding General, First Army, Governor’s Island, New York 4, N. Y., ATTN: Commanding General, First Army, Governor’s Island, New York 4, N. Y., ATTN: Commanding General, First Army, Governor’s Island, New York 4, N. Y., ATTN: Commanding General, First Army, Governor’s Island, New York 4, N. Y., ATTN: Commanding General, Second Army, Ft. George G. Meade, Md., ATTN: AIABB Commanding General, Second Army, Ft. George G. Meade, Md., ATTN: AIAME Commanding General, Fourth Army, Ft. Sam Houston, Tex., ATTN: G-3 Section Commanding General, Fifth Army, 1660 E. Hyde Park Blvd., Chicago 15, Ill., co mma.nding General, Fifth Army, 1660 E. Hyde Park Blvd., Chicago 15, Ill., Commanding General, S~ Army, presidio of San Francisco, Calif., ATTN: AMGCT-4 Commander-in-Chief, Far East Command, Apo 500, c/o PM, San Francieco, Calif.,

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OPOT Division, Corn. Dev. Branch co mmandant, Command and General Staff College, Ft. Leavenworth, Kans., Commandant, The Infantry School, Ft. Benning, Ga., ATTN: C.D.S. Commandant, The Artillery School, Ft. Sill, Okla. Commandant, The AA&GM Branch, The Artillery School, Ft. Bliss, Tex. Commandant, The Armored School, Ft. Knox, Ky., ATTN: Classified Document Section, Evaluation and Res. Division Commanding General, Medical Field Service School, Brooke Army Medical Center, Ft. Sam Houston, Tex. Director of Special Weapons Developments, OCAFF, Ft. Bliss, Tex., ATTN: Maj commandant, Army Medical Service Graduate School, Walter Reed Army Medical Center, Washington 25, D. C., ATTN: Dept. of Biophysics Commanding General, The Transportation Center and Ft. Eustis, Ft. Eustis, Vs., ATTN: Asst. Commandant, Military Science and Tactics Bd. Commandant, Chemical Corps School, Chemical Corps Training Command, Ft. Commanding General, Research and Engineering Command, Army Chemical Center, Md., ATTN: Special Projects Officer Commanding General, The Engineer Center, Ft. Belvoir, Va., AT TN: Asst. Commsmdant, Commanding Officer, Engineer Research and Development Laboratory, Ft. Belvoir, Va., ATTN: Chief, Technical Intelligence Branch Comman ding Officer, Picatinny Arsenal, Dover, N. J., ATTN: ORDBB-TK Commanding Officer, Army Medical Research Laboratory, Ft. Knox, Ky. Commanding Officer, Chemical Corps Chemical and Radiological Laboratory, Army Chemical Center, Md., ATTN: Technical Library Commanding Officer, Transportation R&D Station, Ft. Eustis, Va. Commanding Officer, Psychological Warfare Center, Ft. Bragg, N. C., ATTN: Library Asst. Chief, Military Plans Division, Rm 516, Bldg. 7, Army Map Services, 6500 Brooks Lane, Washington 25, D. C., ATTN: Operations Plans Branch Director, Technical Documents Center, Evans Signal Laboratory, Belmar, N. J. Director, Waterways Experiment Station, PO Box 631, Vicksburg, Miss., ATTN: Library Director, Operations Research Office, Johns Hopkins University, 6410 Connecticut Ave., Chevy Chase, Md., ATTN: Library Chief, Bureau of Medicine and Surgery, D/N, Washington 25, D. C., ATTN: Special Weapons Defense Division - Chief of Naval Personnel, D/N, Washington 25, D. C., ATTN: Pers 15 Chief, Bureau of Ships, D/N, Washington 25, D. C., ATTN: Code 348 Chief, Bureau of Supplies and Accounts, D/N, Washington 25, D. C. ATTN: RD Control Officer Commander-in-Chief, U. S. Pacific Fleet, Fleet Post …