Appendix A ROCKET DEVELOPMENT A.l . HARDTACK PERFORMANCE A.1.1 6 May Test. Four rockets were set up on Site Yvonne for testing during Shot Cactus, an 18-kt detonation; two were located at 3,200 feet from ground zero, and two were placed at a position some 5,000 feet farther down-~island. It was plannedto fire both of the down-island rockets and one of those situated at 3,200 feet to check out the performance of the array prior to operational use on Shot Koa. The remaining rocket was to be left unfired on its launcher so that the results of exposure to the detonation could be observed. The launching equipment for the close-in rocket that was to have been fired was rendered inoperative by the blast, but neither of the rockets at the close-in site were dam~ aged. Both of the down-island rockets fired, and one penetrated the cloud and was recovered from the lagoon. However, it collected no activity, because the cloud height was less than predicted and the sampler head was programedto open at an altitude higher than the resultant cloud top. The second rocket flew in an erratic manner, missed the cloud and sank. Its nose section was recovered from the bottom of the lagoon, and a post-mortem examination indicated that the rocket had probably been damaged by a flying object prior to launching. A.1.2 9 May Test. Two rockets were fired from Site Wilma for system check and nose section recovery practice, but both nose sections were leaky and sank soon after striking the water. The cause of the leakage was not known, but it was thought that a contributing factor might have been the existence of a partial vacuum inside the sampling heads, because they were sealed at an altitude of about 80,000 feet where the ambient pressure is much below that at sea level. To correct this situation, small holes of about 0.040-inch diameter were drilled in the nose sections and coated with a hydrophobic grease, thereby allowing air pressure equalization without permitting the entry of water. Static tests showed that no water entered the sampler heads bythis route. A.1.3 13 May Test. Eighteen rockets were set up for firing at the Koa cloud, but, as described previously, none was launched (Section 2.3.2). A.1.4 26 May Test. After modification and testing of the launching equipment subsequent to Shot Koa, it was believed that the system was fully operational. It was desired at this time to test the complete array with a full complement of rockets. Four rockets were set up on Site Mary, eight on Site Sally, and gix-on Site Wilmafor firing at the Yellowwood cloud. The cloud from Shot Yellowwood did not develop to the extent predicted, and launching signals were sent only to the launchers on Mary and Sally at H + 13% minutes. All rockets launched successfully. The rockets on Wilma were intentionally not launched, because it was apparent that their trajectories would not intersect the cloud. Even of those fired, four were seen to have missed the cloud. 54 ,