II 53 All these organization actions were based on official information from Joint Task Force SEVEN confirming the Atomic Energy ComnissionDepartment of Defense announcement that nuclear tests, under the codeword Operation HARDTACK, would be conducted in the Eniwetok Proving Ground in 1958,22 Colonel Wilifam B, Kieffer, 1409A, assumed command of Task Group 7.4 Provisional on 3 October 1957.12 Colanel Paul Re Wignall, 4935A, was assigned as Deputy Commander on 16 October 1957.12 Colonel Kieffer and Colonel Wignall also similtaneously occupied the respective posi- tions in the 4950th Test Group (Nuclear), Upon assumption of the duty of Deputy Commander of Task Group 7.4 by Colonel Wignall, Colonel Aldeit G. Thompson, 7126A, was released from that duty and was assigned the primary duty of Director of Operations of the 4950th,’4 and the addi- tional duty of Coumander, Test Atroraft Unit in Task Group 7.4./9 Lieutenant Colonel Richard J, Hynes, 9795A, was relieved of the primary duty of Director of Operations and assigned the primary duty of Deputy Director of Operations of the 4950th, with the additional duty as Director of Operations in Task Group Taber6 Upon the organization of the Test Base Unit, Lieutenant Colonel Walter R, Hedrick, Jr., 9353A, assumed command of the unit;1? and effec- tive 7October 1957, Colonel Wilson H. Neal, 1076A, assumed command of the Test Services Unit. yw AFWL/ HQ 4 Vv

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