Three nose sections were recovered. The cap on the first nose section was still intact, probably as a result of a short in the circuit that fired the nose cap removal squib; there- fore, no sample was collected. The second nose section was from a rocket programed to open at 30,000 feet. When recovered, the nose section contained about 60 ml of water. At H + 9 hoursthefilter of this nose section read about 1 mr/hr at the surface. The third nose section was from a rocket programed to open at 55,000 feet. About 100 ml of water had leaked into it, and the surface reading of its filter was 25 mr/hr at H + 9% hours. After this shot, an intensive effort was made to determine the cause of leakage of water into the nose sections. It was found that the ball joint sealing the forward end of the nose- section after sampling could bounce back a small amount after closure, thereby permitting water to enter. A latching mechanism was designed to lock the ball joint in its totally closed position. This modification was then applied to all nose sections. A.1.5 1 June Test. Three rockets wer: fired from Site Wilma to test the modified balljoint closure mechanism. The sustainer motor on the first rocket did not ignite, causing the nose section to remain attached to this unit, which fell into the lagoon and sank. The second rocket was damaged by impact with a coral head. The third nose section was re~ covered intact and was dry inside. This represented a completely successful performance of the system. It appeared that the problem of water leakage into the nose section had been solved. A.1.6 15 June Test. Ten rockets were set up for firing at the Walnut cloud. six were successfully launched (Section 2.3.3). Of these, A.1.7 20-June Test. Because of the presence of water in the nose sections after Shot Walnut, two rockets were fired from Wilmato further investigate the cause of leakage. The nose section of the first rocket failed to separate from the sustainer motor and was destroyed when it hit the reef. The second nose section was recovered in the lagoon, and 50 ml of water was found to have leaked into it. It was conjectured at this time that the low ambient temperature (—100° F) encountered by the rocket at altitude might be freez~ ing and causing distortion of the O-ring seals. A.1.8 23 June Test. A nose section with parachute was dropped from a helicopter at an altitude of about 1,500 feet. It was recovered within 244 minutes after striking the lagoon, and again, 50 ml of water was found inside. The possibility that the impact with the water caused the large rear conical seal to open momentarily was suspected. This was suggested by the rather large volume of water that had entered in a relatively short time. A.1.9 24 June Test. Two nose sections with parachutes were dropped from an altitude of 1,500 feet in an effort to determine the exact point of water leakage. In the first nose section, the filter was replaced by a rubber membrane; and both the fore and aft spaces of the nose section were stuffed with absorbent paper tissue, so any water leaking in would be retained near the point of entry. After recovery, it was found that no water had leaked into this unit. The second nose section, which was the same one used in the 23 June test, was also stuffed with tissue. However, a normal filter unit was used to separate the sections rather than a rubber membrane. When recovered, this nose section was found to be dry inside. There was no difference between recovery conditions on the 23 and 24 June tests, except that the lagoon surface waa rough 23 June and calm 24 June. 55