This report presents results optained [roa high altitude seasuremects made oo Teak ami Orange shots of Operation Eardtack oa July 31 and Avgest ll, 1955, respectively, Johnston Island time. (The dates in cootinental Cnire’ States were, therefore, August 1 amd August 12, respectively.) Originally scheduled and ser up for launch frow Bikini during April, the two Redstomboroe warheads with Launching equigment and associated instmmentation wre moved to Jotostoc Island because of the intéernstivosl situation and ccocern over the possidilicy of retinal turns om the eyes cf islanders within line of site of the 3ikini-launched bursts. Teak shot was burst at an altitade of approxizately 252,000 feet, Orange at approximately 152,000 feet. The reader will note departure from conventional report foraat in chapter Creataent in chat each is a separate entity with author or authors shown in the Table of Courents. References are listed at the end of each chapter which, together with illustrations, may be considered separately from others in che report. All chapters of this report were coupleted by early Spring 1961, with the exception of Chapters 7 and 9. These were delayed until completion of an ex- perimental program to derersine rocker trajectories.