- . aaa ' the crew compartment on uf) special aircraft should likewi./ be filtered. 2. Scientific Control Aircraft The presence of scicntific program personnel in the cloud vicinity . Quring the operation is essential to provide technical guidance ami evaluation of the radiation hazard in terms of cloud structure for the sampling aircraft. On the basis of the observed development of cloud structure, they locate and follow the position of sections of the cloud most likely to contain significant samples, and assist the performance of the sampling mission by vectoring the sampling aircraft to these locations. They also operationally control the total radiation aposures of the sampling pilots according to the relative readings of the radiation instruments relayed to them on the completion of a cloud penetration. Althcugh one of these personnel will be a rated aircraft director, they are not directly responsible for the safety of flight operations or the direction of aircraft to and from the general sampling area, although they may assist in the latter activity. In order to permit these personnel to function effectively, an aircraft is desired with the following gencral requirements: (a) Position: In the immediate vicinity of the cloud from zero time to the conclusion of sampling operations, (bd) Altitude: An initial true altitude of 35,000 to 40,000 feet with capability of climbing to 45,000 feet as required by the cloud structure, (c) Speed: medium speed is desired. To minimize navigation and vectoring problems a Co (d) Endurance: Capable of remining aloft for ten (10) hours. (e) Personnel: Maximm of three3). acicntifie personnel aboard, one of whom will be a rated aircraft director, (f) Communications: (1) Two installed & chunnel.NEF aystens with suitable spares. (2) One HF liagon set. ( (3) Ome low frequency homer designed for continuous operation with sufficient power to permit anproximately a 200 mile ranging capability under operational conditions. (g) Navigation: positioning to within five miles, Capability ef continuous absolute aircraft (h) Special Personnel. Equipeent: Space in the aircraft for scientific personnel should be located to permit direct contact with pilot and should be provided with interphone and oxygen outlets to permit movement necessary, to observe the cloud as required by thc aspect of the aircraft relative to cloud, if not otherwine : provided, means should be made available to keep window areas used Zor observation clear of frost. (4) Back-up: A suitable back-up is required. An aircraft which participates in other test operations may be used as a back-up, provided that it has similar capabilities end can be made available throughout the sampling operation. b. Fadiation instruments: Airborne radiation instruments are required to permit operational control of radiation :comosure within biologically acceptable limite and to wrn