Vv Cloud Sampling Requiremenis for CASTLE The stem from the "rat tnernonuciear cloud was some 20 miles in diameter and climbed to almost 50,000 feet, The main cloud extended from 50,000 feet altitude on up through the tropopause and was almost 200 miles wide, The F-8)G sampler aircraft climbed to their maximum altitude to collect samples from this monster. Scientists, however, doubted whether samples taken from MIKE cloud represented what was actually contained in the cloud, There was also uncertainty about whether the samples were taken from the stem or from the lower portions of the main cloud itself, The size of the MIKE cloud and these doubts about the value of samples taken from it, caused a change in requirements for sampling the Operation CASTLE shots? Within two weeks of the end of Operation IVY, Task Group 132.) officers and the Air Force Special Weapons Center staff began studies to determine what aircraft could be converted to a sampler configuration for higher altitudes, But, before a decision could be made, sampling requirements had to be firm. Late in January 1953, officers from the Air Force Special Weapons Center visited the Los Alamos Scientific Laboratory and again met with Harold F, Plank, Dr, Plank outlined general requirements for cloud sampling and, afterwards, drew up more detailed requirements which were approved by the laboratory and submitted to the new Task Force SEVEN early in February. Because of the questionable samples secured from MIKE Shot, Los Alamos wanted a high altitude saupling vehicle which could at least penetrate the lower portion of the main cloud. 9h AFWLUHO Data from these SWEH~2-0034 \\9 rh te