OPERATION HARDIACK I - TATE: TIME: PPG Time 18 Jun 1958 1500 Linden GMT Sponsor: 18 Jun 1958 0300 SITE: LASL PPG - Eniwetok - West of Yvonne, 4,000 ft from the island 11° 32’ 162° 21' 39" 23" Site elevation: Water depth: HEIGHT OF BURST: WN E Sea level 33 Ft 8.25 ft TYPE OF BURST AND PLACEMENT: Surface burst from barge on water CLOUD TOP HEIGHT: 20,000 ft MSL CLOUD BOTTOM HEIGHT: WM REMARKS: Only individual island dose rates are available. These were obtained from helicopter surveys made by the Radiological Safety organization at H+4 hours. The helicopter survey technique called for the pilot either to land the aircraft at the desired spot, so that a ground reading could be obtained, or to make a slow pass over the desired spot at an elevation of 25> feet. Readings taken at 25 feet were multiplied by a factor of 2 in order to obtain a reasonable approximation of the true ground reading. The basic instrument used in the aerial surveys was the AN/PDR-39 survey meter modified to read up to 500 r/hr. The t-+:® decay approximation was used to extrapolate the H+ hour dose-rate readings to H+l hour. 254