mw 2-45¢ 1. Although the emplacement, suspension, and firing system as used during Operation HARDTACK was employed successfully on the two events, a different system, which should include & more stable platform for the zero firing and instrumenta- tion system, would be desired, 2. More time should be allowedfor the various support groups to determine their requirements and procure and fabricate special equipment. This action would permit better coordination for preparation of facilities. 2.4.2.4 Project 34.4. The Microbarograph Project recorded blast waves from HARDTACK. The primary purpose of this project was to measure blast. waves from the teak and orange events. High temperatures or -wind speeds in the upper atmosphere may cause portions of a blaat -wave to be returned to the ground at great distances, Microbarograph stations at Johnston Island, Lualualei, Oahu, T.H. and French Frigate Shoals were to record these refracted sounds, arrival time and incidence angles. From these records it is anticipated that winds and temperatures at 100,000 to 180,000 feet where the blast waves were returned to the ground, may be interpreted. The secondary purpose of Project 34.4 was to measure blast waves generated near the ground at the Eniwetok Proving Ground. These waves are bent by refraction as they propagate through the upper atmosphere and were recorded at microbarograph stations located at Eniwetok, Bikini, Kwajalein, Utirik, Wotho and Ujeland. The Microbarograph station at Johnston Island recorded an overpressure of 8.4 millibars or approximately 0.12 psi. Arrival time for the blast wave at the recording instrument was approxima tely 193 seconds. This data was obtained for the teak event and together with the orange data will be evaluated in terms of wind ‘eae f ma... lbs PAGE 779