HEADQUARTERS JOINT TASK FORCE SEVEN “ashington 25, D. C. ~J=37300.4 3 December 1953 SUBJECT: Sehedule of Nassages Concerning Detonations During CASTLE TO: Commander in Chief, Pacific ; Navy No. 128, o/¢ Fleet Post Office San Franciseo, California lL. In order that you aay be kept informed of developments during the operational phase of CaSTLE, operational pricrity messages will be sent to your headquarters price to and subsequent to the detco~ nation of each of the weapons and devices in agcordance with the following scheduler a. DeDey ainus § dayst (1) anticipated time of detonation (GC), (2) Information relative to closing of Eniwetok and Bikini air bases. b. HeMoar aiaus:12 hours: (1) Porecast atomle cloud trajectory for the initial 72 hour period after detonation. (2) Radfological outlook for native populated atolls. (3) antieipated radiologiesl impact on air and surfsce routce, ineluding recommendations rolxtive to closing routcs. @. Hetiour plus 30 minutes: dad. (1) Exact time (GCT) of detonation. (2) Safety of personnel. Daily at 2000 hours local starting on DeDay and continu=- ing until significant informticn ceases. (1) Verification or revision of atomig cloud trejectory, Incl 3 to TAB "C* C<te