OPERATION HARDTACK I - TATE: TIME: 26 May 1958 1400 Yellowwood Sponsor: 26 May 1958 0200 SITE: LASL PPG - Eniwetok - SW of Janet 5,000 ft 11° 39' 162° 13' 37" N 31" &8 Site elevation: Sea level Water depth: 75 ft HEIGHT OF BURST: 10.52 ft TYPE OF BURST AND PLACEMENT: Surface burst from barge on water CLOUD TOP HEIGHT: 50,000 ft MSL CLOUD BOTTOM ERTGHT: 30,0CO ft MSL 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 €5 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-l°? decay approximation was used to extrapclate the H+4 hour dose-rate readings to H+l hour. 218