Chapter 3 INSTRUMENTATION and 3.1 . a OPERATIONS INSTALLATIONS For the purposes of Project 9.1, two cameras were installed and operated in each _ of four airplanes by the Lookout Mountain Laboratory. Each plane was equipped with a Type A--28 Automatic Stabilized Mount, which carried one modified K-17C camera and one 35-mm Eclair motion-picture camera. The 35-mm cameras wereintended to operate at about one frame per second, to document the rapid rise of the cloud during _ the first five minutes. They were equipped with timing elocks. The K-17C cameras were provided with special shutters to permit long exposures under dim lighting con=ditions and were planned to take three photographs every minute during the early stages and to drop back to a slower schedule later on. The K~17C cameras were provided with data recording chambers to record: (1) the time at which each frame was exposed, (2) aiming of the camera by meansof a gyro-controlled compass card, and (3) tilt of the stabilized platform by means of a bubble-level. _ One installation was placed in the RB—36 aircraft, which was flown at about 40 ,000 feet on every shot. This plane was available to Project 9.1 for only the first 10 minutes . after detonation; it then performed duties for Program 11 and Task Unit 9 to the exclusion of Project 9.1 interests. Similar installations were made in three C54 aircraft, which flew at 10,000 to 14,000 feet for cach shot. These planes were available for an hour or more and were shared with Task Unit 9. The original plan called for placement of all planes in the two western quadrants to permit photography of the cloud silhouette against the dimly iNuminated eastern sky. ’ Distances and lenses were specified to cover a field of view approximately 150,000 feet high and 350,000 feet across in the vectical plane at ground zero. This requirement was based on observations taken during Operation Ivy. The ship's navigator was requested to supply information as to the distance end bearing to ground zero évery minute, together with supplementary data on the plane's heading, course and speed. ' Although the schedule was tight, all equipment was installed andtrial runs were made before leaving the United States. Thase runs were apparently satisfactory. Trial. runs were also made in the forward area, with the primary object the determination of the pre-dawn sky light-levels. It was found that the available light was marginally weak but still exceeded pessimistic expectations. 3.2 OPERATIONS The plan of operation was relatively simple in principle, but success depended upon good luck as well, as on proper functioning of individuals and equipment. Serious loss of data or even complete failure of the mission could result from the failure of a single link in the chain. For example, incomplete navigation data can spoil an otherwise perfect 14 SECRET 1 ane ehate Lie een OT