protection by fixed-density optical filters was explored. velopmental protective electronic Results at yields o shutters were field-tested. PEERjomonstrated that the blink reflex does not protect against chorioretinal ; D, caused retina} Two types of de- burns. The lesions at 8.1 statute miles. The device of produced burns at 7.6 statute miles but not device far as 14.4 miles. Burns were not obtained from devices of eld at distances of 12.9 and 21.6 miles. The lower effective range of burning at the PPG is attributed to higher atmospheric attenuation from excessive humidity and salt spray from the reefs. Note is made that additional information is needed in order to determine the limiting distance for retinal burns at and, especially, higher yields. Both the Waadevices produced retinal burns in two of the eight animals exposed to only the first pulse. Both detonations produced burns during the second pulse. The optical filters tested at near-threshold distances prevented retinal burns. At intermediate distance, filters reduced the incidence and severity of the lesions. The results obtained on protective shutters were inconclusive but can guide future development. 2.1.5 Program 5, Aircraft Structures Program 5 included nine projects primarily concerned with the determination of the capability to deliver nuclear weapons of six Air Force types of aircraft and one Navy aircraft. One project, sponsored by the AFCRC, provided thermal-measurement support, and another will provide data on the thermal lethality of a nuclear detonation to certain basic missile structures and materials. Secondary objectives of the aircraft projects were to (1) obtain data for basic research and design of future aircraft, and (2) verify or correct the present analytical methods for the prediction of weapon-effect inputs and the resultant responses by the aircraft structure. _ A test of an Air Force B-47 successfully obtained data for wingbending loads from 39 to 91 per cent of design limit and temperatures of up to 550°F on thin-skinned control surfaces by the use of high-absorptivity paints. Some measurements of the effects of side loads on the aircraft structure were also made. Correction of the Weapon Delivery Handbook for the B-47 will be made after data evaluation. A test of an Air Force B-52 proved its capability to deliver high-yield nuclear weapons. Extensive thermal, overpressure, and gust measurements will result in fairly clear definition of the safe-delivery envelopes. It appears that 0.9 psi will be the limiting overpressure, instead of 0.8 psi as had been predicted prior to the test series. The ability to predict structural - 33 APS UME, 3/