Effects of Radiation on Transistors in the First Telstar Satellite

The response of the Telstar communications satellite to its enviromnent and to command experiments indicated the characteristic ionizing radiation effects on transistors, the variation of degradation with collector voltage, the recovery with removal of voltage, the sensitivity to dose rate, and the eventual effect of total dose. Comparison of laboratory results with those under actual orbiting conditions is a significant factor in indicating the appropriate testing techniques and exposure levels to be used in further studies. It was concluded that the emphasis in development of radiationresistant circuits must be in the direction of reducing or eliminating the radiation sensitivity of transistor types. Tests indicated the insensitivity of most evacuated types of silicon transistors and that many planar types, even gasfilled, suffer only limited degradation in the region 10/sup 6/ to 10/sup 7/ rads. Applications of the findings in the production of transistors suitable for long life in satellites are discussed.(C.H.)