OPERATION HARDIACK I PPG Time Aspen GMT TATE: 15 June 1958 14 June 1958 TIME: 0530 1730 Sponsor: SITE: UCRL PPG - Bikini - SW of Charlie 4,000 ft from the island 119 hit 165° 16' 27" ak" Site elevation: HEIGHT OF BURST: CLOUD TOP HEIGHT: Sea level 10.82 ft TYPE OF BURST AND PLACEMENT: 48,600 ft CLOUD BOTTOM HEIGHT: N & Surface burst from barge on NM water 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-1:2 decay approximation was used to extrapolate the H+4 hour dose rate readings to Htl hour. 246