OPERATION HARDIACK I - DATE: TIME: PPG Time 28June 1958 0630 Elder GMT Sponsor: 27 June 1958 1830 LASL SITE: PPG - Eniwetok - SW of Janet 4,000 ft to nearest edge of island 11° 39' 162° 13' 48" 48" Site elevation: HEIGHT OF BURST: N §£ Sea level 9.17 ft TYPE OF BURST AND PLACEMENT: Surface burst from barge on water. CLOUD TOP HEIGHT: 50,000 ft MSL CLOUD BOTTOM HIGHT: NM REMARKS: Only individual island dose rates are available. These were obtained from Radiological Safety organization helicopter surveys 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+4 hour dose-rate readings to H+l hour. 262