Livermore Laboratories, believed a guided missile capable of operating between 80,000 and 100,000 feet altitude was needed. They wanted such a vehicle to enter the cloud between five and ten minutes after detonation and be capable of collecting both gas and particulate cloud samples, The vehicle, of course, should be recoverable, and have the ability to land on a 5,000-foot runway.~° In his final report on Operation CASTLE, General Estes pointed out that, because manned ‘sampling aircraft were the best vehicles available, scientists were forced to accept them, even with their limitations, A study of guided missiles for sampling had not been accomplished during CASTLE because time was too-short, missile experts were not available, and cloud temperatures, gusts, and radiation data were not available. General Estes recommended further study of guided missiles for this purpose, capable of operating from 100,000 to 125,000 feet altitude, 1 Modifying Sampler Aircraft for CASTLE In spite of the efforts for B-57 aircraft and the current thinking about guided missiles, Task Group 7.) sampled CASTLE shots with F-8) jets, plus three Featherweight B-36 aircraft, Both types went to modification depots before being shipped to the Pacific Proving Grounds, In August 1953, representatives of the Air Materiel Command, Wright Air Development Center, the Atomic Energy Commission, AFOAT-l1, met at the Mobile Air Materiel Area depot to plan modifications needed for CASTLE. The F-84G samplers were to be rewired, have new electronic equipment 97 AFWLJHO SWEH-2~-003) il > en,