capability for multiple delivery tactics could be defined. The Navy sponsored a project in which two A4D-1 aircraft participated jointly in several shots in order to measure weapon in-puts and structural responses to high yield weapons. The final objective was the correlation of the data with that of the Plumbbob tests in order to define the high yield (megaton range) weapon delivery capability of the A4D~1. From the preliminary data obtained it was determined that measured stresses were consistent with predictions obtained from the analytical techniques employed. I ia anticipated that additional data obtained from wing pressure instrumentation will assist in further refining the dynamic analysis. Thermal inputs were generally substantially lower than predicted, although the temperature response calculations based upon measured inputs in general showed good correlation. I was concluded that the data obtained, when combined with that obtained from Operation Plumbbob and the aircraft performance characteristics, will permit the definition of the nuclear weapon delivery capability of the A4D~-1 aircraft. Effects input and structural response of two FJ-4 aircraft were measured. The information obtained was concentrated in inputs and effects from higher yields in order to correlate with data obtained from the lower yields of Piumbbob and confirm the Class D delivery capability of the aircraft. In general, excellent correlation of blast response data was obtained, verifying the dynamic analysis techniques used for predicting structural responses. I was concluded that response data have been obtained over a sufficiently wide range of yields and incidence angles to permit subsequent definition of the Class D delivery capability of the FJ-4B aircraft. Program 6, Test of Service Equipment and Materials . This program had a wide range of project station locations: Wake Island and Eniwetok, Bikini, Kwajalein, Kusaie, Wotho, and Rongelap Atolls. One project to study the wave form of electromagnetic pulse from a nuclear detonation used two sites: Kusaie, 420 miles from Eniwetok, and Wotho, 240 miles from Eniwetok. The objective was to make broad-band measurements from 0 to 10 Mc at ranges up to 460 miles. The measure- ments were not expected to be radically new. Although improvements in equipment were incorporated, the primary concern of this project was to increase the cataloging of wave forms. The data, which are in good agree- ment with those obtained during Operation Redwing, indicate that device yield and range and the presence of a second stage can be determined from wave~-form parameters. Another project, with stations at Wake Island and Kusaie, studied iono- spheric effects of large-yield surface detonations. In agreement with re- sults of Operation Redwing Project 6.3, the energy responsible for the first disturbance in the ionosphere above Kusaie waa propagated with a mean velocity of 20 km/min. Also corroborating previous results, the second disturbance resulted from energy propagated with a mean velocity of about 18 km/min. The first effect has been postulated to be due to a compressional wave and the second to a hydromagnetic wave. The fact that the first effect was seen approaching but not receding is indicative of the shape of the ion-density variation associated with the disturbance. Two projects participated during shot Umbrella to obtain effects data $2