gu 2.1.8 | 2-25 YUCCA VHA PROGRAL The overall objectives of the VHA program were to determine the effect of extreme altitude on pertition of energy in anuclear explosion, and on the radii of effects of the various phenomena, and to determine scaling laws of these effects as a function of altitude and yield. Scientific results t: been discussed in previous sections of this chapter, and of interest hc -~ -r the weapon system, the baloon carrier, and aircraft modifications. One p-o-- ject supplied the warhead, the fusing and arming, the radio cormand system, and the monitoring functioning for the device. another project pro- vided the carrier, and supplied a 128 foot » 2 mil polyethene balloon which was to lift the device and associated scientific equipment to altitude. . Test flights from various launching sites conducted over the previous 18_ months had shown that launch from eircraft carrier, with a deck wind velocity of near zero, was the most reliable method. The balloon wes launéhed:-fromtheUSS. Eexcr.. The total ‘woight of the system was 1295.5 pounds with a payload of 761.5 pounds. The psyload con- sisted of the device and five canisters containing instrumentation for measuring pressures, thermal and gamma radiation, neutron flux and the electromagnetic pulse, Due to command transmitter failure prior to zero, no weapons effects data of significance was received from the five suspended canisters. Aire craft instrumentation was successful in fulfilling project objectives. 22 TASK UNIT ONE, LASL PROGRAS 2.2.1 critppooe AN \L RG INTRODUCTION Task Unit One carried out experiments to determine the performance of the devices fired; to mecsure physical qumtities of interest in weapon de= sign; and to understand the mechanisms by which the verious effects of the ? Li, ‘<, devices are produced. 4 ee Le In Operation HiRDTACK new methods were used to deter= qua pace FY /