IV F-8) pilots, These pilots were to arrive at Kirtland Air Force Base on 2 February 1953 to begin training and were to be put on temporary duty with the group.” - In December 1952, Colonel Karl H. Houghton, Human Factors Branch, Research and Development Division, Deputy for Operations, Lieutenant Colonel Fackler, Plans and Operations Division of the 925th Test Group (Atomic), and Dr. Plank of Los Alamos met over the sampling problems expected for Operation UPSHOT/KNOTHOLE. The length of exposure of the samples to be gathered from the nuclear clouds was determined by the use these samples would receive by the various laboratories, The Atoanic Energy Commission's Biological-Medical Division declared that 3.9 roentgens accumlated exposure was the limit for any individual during the test. Therefore, the radiation exposure a pilot could absorb for each shot was figured very closely, There were ten shots scheduled and to gather required samples from the first five shots, pilots would be exposed to a total of 2.9 roentgens. For the samples needed from the second five shots, the pilots would have to take a total radiation dosage of 2.9 roentgens. But an eleventh shot was added to the series and this dosage increased to 3.1 roentgens. These figures were forradiation received while actually in the cloud and did not include radiation absorbed while near the eldtid or while flying the sampler. These factors convinced the two colonels and Dr. Plank that two groups of pilots were necessary for the program; one group to sample each half of the test, Also, to stay within the limits of the allowable dosage, all secondary sources of radiation had to be reduced as mch as possible, 81 APHLIHG One of the ways for doing SWEH-2-003) \ 60