Operation Redwing, a Preliminary Report of () (Erie) (Deleted)

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Project 5.7 - Themal Flux and Albedo Measurements fran Project 5.9 - Weapon Effects on Missile Structures -d project 6.1 - Accurate Location of an Electromagnetic Pulse project 6.5 - Ana~sis of Electromagnetic Pulse Producedby

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Radio Chemical Analysis ......ls.. ~aot~on Measurement, Land and Air. Time and XR Wireless Mea Surements l

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Thh is a pre~ry report, and therefore, does not give either complete or final results of the work of the ~rious projects, NO information on the constriction of the device is included in order that . the cbssification may be kept to Secret Restricted Data. . the center~f Runit_Island, Enhetok Atoll, at 0615:29.3, May 31, 1956. ed to give a field in the .—. .— ~.

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Obsened Weather at Shot Time F*. ()-~- Eniwetok Atoll, Scientific Stations and Fig. 0-2- -t Isti - Scientific Statlona

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ENIwETOK OBSERVED WJMTH~ FOR 31 my 1956 ERIE. DETONATION TIME 0615M Sea Level Pressure 1009.1 mb Free Air Surface Temperature 80.3% Dew Point Temperature 73.5°F (Wet Bulb 75.4% Surface Wind 100° at 12 Ms; gusts to 15 kts Visibility Over 10 miles be at 3500-4000 feet appraxi-mately10 miles east of station). 2/10 altocumulus; bases estimated 19,000 feet; thin but opaque (possibQ’ 10/10 cirrostratus; bases estimated 30,000 feet; no tops reported (9/10 No showers reported in local area. In general appeared clear and exceptionally gOOd risibility. No haze apparent. STATE OF SEA Ocean Side: Wave heights 4.5 feet, period 5 secondst ~rection 090°. Presmllw Height Temperature

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To gain information regarding the behavior of lid reflexes under the high illumination produced by atomic devices; to further evalmte the blink reflexes as a protective mechanism against chorioretinal To gain information on shutter and filter mechanisms for eye protection against chorioretinal burns caused by atomic weapons of various types and yields. The basic instrumentation for t~s shot was identical with that + exposure sites; TOM, URIAH, VAN and CHINIEERO (ALVIN); which are nearer to ground zero than the original exposure facility at JAF’lA.N(DAVID). While this change did not entirely succeed in bracketing the threshold of burn production, it did, however? prtiuce a spectrum of ~n severitY which “otherwisewould not have been obtainable on any single shot. Electronic instrumentation and timing signals were employed only at the station on JAF’TAN(DAVID). Temporary racks, holding ten rabbits each, were used for each of the four forward sites. Anlmds placed in these racks were used for blink reflex and filter studies onlY. d Chorioretiml burns were pro~uced in & of 113 rabbits and 6 of 8

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monkeys exposed to the flash of this shot. Lesions resulted at all stations.-Calculated caloric yields at the exposure sites ranged inversely corresponding to distmces of 2.7 Blink Reflex Studies Blink reflex exposures prohced chorioretinal damage M 21 of’38 rabbits and 6 of 8 monkeys. Evaluation of blink reflex the (In this case, the time and duration of eye exposure) avaits appraisal of the high speed photography of the anima?.eyes during the explosion. Laboratory studies using increasingly powerful photoflash Wbs reveals a relatively constant blink reflex time of approximately 320 ms for rabbits and monkeys and about 160 rnsfor man. blink reflex times and recognizing the twofold greater relative opening of the rabbit pupil, earlier investigations estimated that the rabbit is susceptible to retinal burns at distances about 25 percent greater than those equally harmful to man. !&analogy therefore, the production of burns at 8.1 statue miles ex-ttrapolatesto 6.5 miles for man.. As eviflencedby the data it was noted that smaller (and apparently less severe) lesims were encountered at increasing ~istances from the fireball. Details of burn pathology must a~mit laboratory study vhich cannot be”accomplished at the Pacific Proting Grounds. It is of interest to observe that retinal hemorrhaging in this exposure series was associated with what appears to be lesions of intermediate severity. This is In contrast to the findfngs of pretious investigators who noted hemorrhaging in connection with the most severe additional information on the incidence of this burns. It maybe that reaction andjor other

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phenomena may be significant in the development of a comprehensive subjecti~ading system analogous to that used in the evaluation of the cutaneous flash burns. Retinal burns were sustained by 10 of 32 rabbits exposed behind staggered shutters at JAPTAN (DAVID). According to preselected shutter timing, two burns were produced during the initial 7-to-10 ms of the weapon flash. Both burns were located centrally In the rabbit eye and appeared almost pin-point in size. These lesions, while definitely minimal, were nevertheless discernible on a 24 hour re-check when they were documented by fundus photography. Since the time of the first minimum is calculated as occwing < 4 it would seem that the burns were prwluced by the energy of the first pulse alone. If true, this finding becomes of interest in considering the time of closing for protective shutters. The low inci~ence (12.5 percent) of burns during the first 50 ms of the explosion somewhat minimizes the possibility of si=-ificant injury produced by the first pulse. Staggered shutter exposures to the initial 60-to-250 ms of the detonation caused burns in about 50 percent of animals exposed during these intervals. The ti..eto the second madm-un is calculated at it is apparent that this group of animals were subjected, not only to the energy of the first flash but also the greater portion of the second pulse. Resolution of upon appraisal of the of the explosion. actual shutter spee~ In all cases is contingent high speeilphotography accomplished at the time

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In the ~elayed shutter exposwes, 6 of 16 rabbits sustained retinal burns. The lesions were prcduced mostly in cases where the exposure included the maxhnlm or near maximum flux of the second Increments of the flash beyond 0.6 seconds did not produce burns Burns produced behind filters at URIAH and VAN at 3.O and 3.8 miles, respectively, were simfhr in size and appearance to blink reflex lesions sustained on JW1’A??(DAVID) at 8.1 miles distance from ground zero. From this it is inferred that the filters reduced the caloric dose and dose rate at URIAH and VAN to a level belov that which- .. could produce burns. These shutters were inoperative at H hour due to a fire in the wiring circuit at H -L minutes. With the grid mechanism fully open, the shutter still reduces the incident visible light by about 60 percent. As a first approximation it is estimated tht the ener~ re @ing the rabbit eye was effectively reduced .- ,,a It is of interest that no lesions vere produced in the animals behind the protective shutters. \rithinthe l~ts ~Posed by the yield of the weapon and the blink reflex time, it would appear that the threshold of burn production for this event lies between The blink reflex time for animals and man is not sufficiently rapid to protect against the flash from an atomic detonation

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.6 h air burst of this size at dawn of a clear day (93 percent atmospheric transmission) is sufficient to produce chorloretinal burns yieldawi these distances the energy of.the first 50ms of the ,,<.b~ detonation, and particularly that of the firgt is of little significance in the production of Incidence of burning occurre~ in those animals inclu~ed the period from 60 through 200 ms. burns. The highest whose eye exposure There is limited evidence that burns could be produced at somewhat greater distances under identical con~itions of exposure at the pacific Proving Grounds. It is be~ieved, however, that chorioretinal burning assumes its greatest significance for the pilot and air crevs at high ‘ altitudes where specific absorption effects by salt water spray and excessive humidity are nat factors of atmospheric attematlon. Additional information is nee3ed on the spectrum of the atomic flash in order to predict the iiistan~esat which burning is significant. The rate of delivery of thermal energy is of prime importance in the production of chorioretinal burns. At near-threshold distances, filters of the colors and densities test~ till prevent chorioretinal tins; at intermediate distances these filters will reduce the incidence and severity of the lesions.

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The primary objective of this test was to measure the gust effect of a 10U meld nuclear weapon on a B-66B aircraft in flight. Instrumentation of the B-66 for this shot consisted of 60 thermocouples and 73 strain gzges at 7 stations on the left ~ing} 9 thermocouples and 10 strain gages at 2 stations on the right whg, 34 thermocmp~es Znd 18 strain gages at 7 stations on the left stabilizer, and 9 thermocouples and 12 strain gages at 3 stations on the right stabilizer, plus 63 channels of correlating information. - The B-66 abortd their participation on ERIE. pilot could not get one en~ine started just prior to take-off time. The E-66 was back in comissfcn for the next event,mm (FLATHEAD).

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The objective of this test was to measure the effects of a IOW yield nuclear detonation of an in-flight E-57B aircraft weapons system. Out of 220 channels being recorded, 10 data channels were lost for various reasons. They have been repafred, or replaced by spares. AIRCRAFT POSITION IN SPACE The JB-57E was flylng at an absolute altitude of 1O,I-4Ofeets ~ heading 052° T in a tail-on position at to. Horizontal range to ground zero at to was 3829 feet (aircraft traveling at 710 ftisec). Aircraft mined to & ~,006 feet beyond ground zero. Heading same as to? althermal energy measured was Gust: Totgl gust load at time of sh Overnessure: Peak overpressure was

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Sideloads F-8Q? - The objective of this partici~tion was to study the dynamic response of fighter structure to anti-symmetric Waiter - Instrumentation of primmry concern consisted of 37 thermocouples locate~ in the right flap, right aileron, right wing, right stabilizer and the engine inlet and outlet. Correlative instrumentation consisted of time zero fiducial signal~ radiometers and calorimeters located at Sta. 80j bottomside of the fuselage. %rley - The instrumentation consisted of strain gage bridges located at Sta. 90 and 150 on left and right wing; Sta. 365 on the fuselage; ~t. Sta. 12 and 35.5 on the left and right stabilizer and h’.L.20 and 53 on the fin. The forementioned strain gage bridges yielded bending moment information. Structural responses were related to energy inputs with overpressure transducers located on a nose boom and in the sides of the fuselage. A total of 100 channels of information were capable of being recorded. AIRCRAFT POSITION IN SPACE The aircraft was flying at an absolute altitude of an inbound heading of 050° 30’ T at to. The horizontal offset were - 8,083 feet and 12,024 feet respectively. feet offset; and / 830 feet horizontal range. These Positions were very close to the intended positions.

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- Maximum irradiance measured Total thermal energy measured was in side fusela e bending. Out of the 100 channels recorded, there were 3 channels that . failed. In addftlon, the two fireball cameras were turned on too - tion of Waiter (Capabilities F-8@) vas not planned

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The objective of Project 5.6 is to determine the responses of w in-flight F-101A aircraft to the thermal, blast and gmst effects of a The aircraft was instrumented with radiometers, pressure traducers to measure the theml and blast inputs and with strain gages, thermocouples and various other instruments to measure the aircraft responses to the inputs. For thfs shot, the aircraft WS positioned to theoretically receive 7 lcmd on the stabilator lxsed on the pzsit5~ning yield. The aircraft was to fly at 12,000 feet absolute on an inbound heading of 050~ at a TAS of ~o@ fFs. It ws planned thet the aircraft Occ”’’ngd later with the aircraft o~-ergromd zero. Actual shot day pcsit~on showed the aircraft to ~7,540 fert short of ground zero at To with shock arriving later with the aircraft being 390 feet short of gro~d zero. Dar~ge: There was no apparent dmage to the aircraft. mentation. Of the 50 osclllo~rap? recorded Faracneters,only three positively did not prtiuce d~t~. tie radiometer ~-asburned out prior

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to flight time; one accelerometer vas unreadable due to defocusing of its galvanometersand one calorimeter, although functioning properly$ was not considered reliable due to its large range and small deflection.. — Three or four thermocouples may have been malfunctioning but, due to the small temperature rises existing, it vas impossible to definitely determine. lkcessive vibration of the photo panel again occurred at shock arrival, rendering two frames (.125 see) ~readable. All 26 gages functione~ properly and no data was lost. Gust Data: The aircraft experienced a multiple indicating that it was above the triple #nt pth. measured was about on the first shock, about half that on the later, and half again on a third shock~~ seconds IateT. Gust response was about for torque and e(ucRo’’E)*Future positions will be revised to account for the new load Data: Thermal response vas again considerably less than T of about 300F was experienced on the honeyconb surfaces. Radiati~~ A reading of e“ was taken from the pilots film ln~ge. - was predicted bsed on positioning yield. General: The participation was again successful from this project’s standpoint. Gust responses were generally higher than previously experienced and the data collected has thus far correlated excellently

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project ~~~- Thermal Flux and Albedo Measurements from Aircraft - The objective of this shot was to obtain thermal flux and albedo infornntion of a nuclear detonation with airborne calorimeters, radiometers, and sixteen millimeter motion picture cameras. Instrumentation within the purview of l?roject5.7 which was installed in the B-57 included nineteen h~L calorimeters and two NRDL radiometers for measuring the direct and surface reflected thermal =“ These instruments possessed mrious fields of view and T were suitably filtered to obtain qualitative spectral distribution information. Six GSA? N-9 cameras were utilized to obtain photographic coverage of the fireball, the ce.rth’ssurface, and of cICIMS beneath the aircraft. Two of the cameras oriented towards ground zero were equippe3 with spectroscopic attachments to obtain continuous spectra in the visible region. Of the other two tail position cameras, one cm.era had a blue filter and the other had a red filter for the purpose of obtaining pictures at both extremes of the visible region of the spectrum. The remaining two cameras were oriented vertically for the purpose of obtaining photographic coverage of the ,earthls surface and of clouds beneath the aircraft. Instrumentation installed in the B-66 consisted of ihe basic twenty-one thermal instruments, and twelve cameras. Information of the position in space of each aircraft is containti

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in the postshot reports of the following projects: ?%oject 5.3, E-66 aircraft; and Project 5.f+pB-57 aircraft. Thermal: The preliminary value of total thermal input to the aircraft obtained on Project 5.7 instrumentation is included in the postshot report of the appropriate project indicated above. Photographic data: of the twenty cameras under the purview of Project 5.’7,twelve were not run at all because of the abort of the B-66. Of the six cameras in the B-57, the blue filtered tail camera suffered film breakage and obtained no pictures. This film was destroyed. Apparently reascmably good results were obtained with the remaining five cameras. The two cameras equipped …