tracked for periods of 48 hours or longer, end could be pesitioned cask hour, & good system would be avatiable fer tracking the detrie itself, Unfortunately, the balloon project was wiewceessful die ts poor precleunshing checking procedure, as ineufficient mumier of balloons te eever nore than one oF two flights per shet and inproger typs balleuns for flight at the selected 40,000 foot altitade. Tis type project however, has potentialities, and should be reinstituted on a larger seale for future tests at the Paeific Proving Ground, @. Results from previous cperations. Die to the linised number of serface shots detonated pricr to CASTLE, only a limited ancunt of data ws available on the lang range fall-out aspeets of this type burst, and in particular, caly the close-in phencmena were availstle ferthe one high yield type. dz a consequence,the following gaierel tocls end assumptions were used in the plaming for C/STLE fall-out forecasting: (1) The IVY MIXE early cresmdnd and uprd.nd iso-intensity Linse were plotted as an cverclay on Budinl itall amd eseumed to ropresent (eit allownnces nade for differmece in yield and ahot conditians) tre close-in contamination that could te expected from « high yield lant surface shot. This information was reasorably useful, however, ag the operations progressed, a new technique to define close-in fall-out was developed. Tie method (Inelosure 3 of Tab D) developed by Dr. Thomas White, H-Div., LS, appears promising, and is being further refined for future tests. (2) Clese-in intensities fron barge shots in the lagoon (in approximately 100 to 150 feet of water) were asgumod, due to the rolatively small amount of solid material available, to be on the order of 1 to 10 55