: en nee | est » ary sample. collected at CASTLE it is del_ted thet the sixaprin 47,000 tint altitude of 42,000 feat true and final aititode of at lesst trueover the tine intervals mentioned in gatagraph daa DELETED 1% is, ' erefare, the 9] © on oftheour high yield CASTLE shots from as high into eu ofn ldbe aow rea * pain reyofthe cloud as possible and to check thea sanocle should spec This it. with altitude samples by comparison e alight +ine at at least 55,000 feet true at atout RY, hours and should reguir male orde © sampling area 55,000 feet of epproximately one-half hour insthe prove by this des altitu lower from sample one or two cloud nenetrations. Unless , comparison generally to be as representative as the high altitude sample 2% y would be desirable on "super" shote after CASTLE to collect as many of the primar aa in ned mentio As . higher or Samples as possible at altitudes of 55,000 feet feet wo paragraph 2c, the apparently lower rate of cloud dispersal sbove 50,000 make such a capability serve the additional purpose of making it possible to plan ility of to sanple between b to 6 hours after shot time with a greater probab guccess when unfavorable wind conditions exist at lower altitudes. 3. Operational Requirements . a. Aircraft oO es 1. SamsBhingsizerart are required to provide the sixprimary senoles : The aircraft for the six primary Semples should have the flight time capabilities in the wicinity of the cloud and the epocial sample described in paragraph 2a. stated in paregraph 2c and corres>zonding altitude capability stated in 2d. Jn order to minisise exposw'e during return to base, these aircraft should use axial flow engines with turbine and air inteke located not less than ten fect from crew compartment. They should have a speed performance of asproximately 0.8 mach and be capable of carrying high performance filter devices. These devices should be equipped with rainproof valves and with a sample radiation measuring instrument to be read in the oockpit. Their location on the aircraft and the de- sign of the filter element should minimize crew, radiation and permit safe removal of the intensely radioactive materials collected and the transportation of these materials. The design of the filter element should also be integrated with re- quirements based on leboratory handling operations. All air entering the crew compartacnt for heating, ventilating and pressurisation purposes should be filtered to prevent the entrance of radioactive cloud particles. les Alanos Scientific Laboratory also has = general requirement that the sampling aircraft be capable of carrying ges sampling equipment. As a result of a cooperative arrangement it is expected that details regarding this requirement will come from another agency. it retains, however, the greatest importance to this laboratory. The special samole aircraft should have the altitude and flicht time characteristics in the cloud vicinity stated in paragraph 2d. Its speed and engine type may be whatever is rejuired. For a medium speed aircraft, it is suggested that the "shoe-box" type filter device developed by Tracerlab, Inc., (08reset be siepted fornae. if a higher speed jet-type aircraft is used be °‘developed wi sugges a filter device sinilar to tthe tyxe used on IVY thin the shape of the wing tank used on the aircraft, The air entering