the dosimeter worn by the pilot in aircraft 831. Radiation recorded by six of the nine film badges ranged from . Information from the remaining three film badges, located at the Pilot's right leg, left sleeve, and left vest is not available. The pilot's exposures were both greater than . Project 5.3 was very similar to 5.2, focusing on the effects of the blast on the structure of two test FJ-4 aircraft. Radiation from film badges on aircraft 467 ranged from , and for aircraft number 310. In Project 6.4, the Army Signal Research and Development Laboratory (SRDL) investigated the electromagnetic pulses post-detonation, utilizing two instruments, one at Wotho (roughly from Enewetak) and one at Kusaie (around from Enewetak). Though Cactus is mentioned in Project 6.5, whose goal was to study the radar echoes from the fireball, it is not clear what destroyers were involved if any. Destroyers for the Teak, Fir and Yucca tests are explicitly stated. Project 6.6, the lasts of the projects that involved the Cactus test, sought to measure the physical properties of the stabilized radioactive cloud following the blast. Koa At 0630 on May 13, the Koa surface device was detonated at the western side of Dridrilbwij. The size of the blast was , around 76 times larger than the yield of the previous surface test, Cactus. The test was conducted in a large water tank. Within 17 minutes of the blast, surface clouds reached approximately . Nuclear fallout predictions for Koa were larger and covered a broader range than Cactus, with significantly higher radiation levels, an order of magnitude larger, in the immediate region surrounding the blast. There had been a larger nuclear barge detonation, the Apache test, off the island of Dridrilbwij two years prior in 1956, during which the island survived. The detonation of the Koa device, however, caused complete destruction of the island. The Department of Defense (DOD) sponsored a series of experiments for Koa: Projects 1.4, 1.7, 1.8, 1.9, 1.12, 2.9, 3.2, 3.6, 5.1, 5.3. 6.4, 6.5, 6.6, 6.9. and 6.11. Project 1.4, which sought to study land craters post detonation for several shots, took ground survey measurements from surface zero out to . Detailed measurements could not be made until four days after the blast due to radiation levels. Using a boat, the majority of the crater was mapped, though some measurements could not be made until 1959 due