II
Book Message.
54
‘The preliminary book message, which had as its pur-
pose the constitution of authority for Air Force Commands to begin ini-
tial planning for Operation HARDTACK, was issued by Headquarters United
States Air Force on 29 April 1957,
A draft of the final book message, more extensive and detailed than
the preliminary book message, was prepared by the 4950th Test Group and
forwarded in August 1957 to Air Force Special Weapons Center for subniasion to Headquarters United States Air Force.
The final book message,
after some two months of coordination and revision, was published on 11
October 1957.7? ‘The message stated that on 24 September 1957, the Joizt
Chiefs of Staff approved Department of Defense participation in Operation HARDTACK, a series of atomic tests at the Eniwetok Proving Ground
beginning about 1 April 1958 and ending approximately 15 July 1958,
To
support this operation, Headquarters United States Air Force in the mes—
sage directed the organization of Task Group 7.4.
By the date of the
publication of the book message, however, several elements of Task Group
7.4 had already been designated and administratively organised,
Only
the Test Services Unit, drawn from Military Air Transport Command resources, remained to be organized,
This unit, as already desoribed,
was subsequently organized by a general order published on 21 October 1957,
According to the book message, the Test Base Unit was to consist of
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a support squadron and a helicopter element; the Test Aircraft Unit waa
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