high altitude sampling missions could then be compared with MIKE samples to determine how representative the F-8)G samples on IVY had been, The sampling officers speculated that an aircraft to perform this high altitude mission would have to operate at or about 55,000 feet altitude for at least one-half hour, long enough to make several pesses into the cloud. Should the samples prove against the F-8LG aircraft, then another aircraft would be chosen to become the permanent sampling vehicle, Los Alamos scientists required, also, that the sampling device on the high altitude aircraft be as efficient as those mounted on F-8lG aircraft, but with more area for sampling raper! Unmanned Samplers for CASTLE Altitude limitations of sampling aircraft also caused some discussion about using unmanned vehicles again, samples, Drones had gathered the first cloud However, during Operation GREENHOUSE, Dr. Plank supervised firing rockets at atomic clouds, The experiment, at that time, resulted in no sampling results, QE shot pusted the main cloud so high crerrsraninaia that even the best mamed aircraft could hope for little more than to sample the lower fringes. Dr. Plank pointed out that the B-57, apparently the best of the available aircraft for sampling, would penetrate the cloud some four to six hours after detonation and expose its crew to about 3.5 roentgens, Samples gathered by a guided missile, or some other vehicle, would possibly be about ten times more valuable than those gathered by the B-57. Such an unmanned sampler should be capable of sustained horizontal flight between 55,000 and 75,000 feet altitude, 95 APWLWO } Dr. Plank said, and be SWEH-2 -0034, 1 vk oo \b | awe