An Estimate of Radiation Effects on Electronic Compoents for the Lunar Excursion Module

The various radiation sources (solar flares and natural and artificial Van Allen Belts) to be encountered on the Apollo Mission have been compared with regard to effect on electronic components. It is found that a large Class 3+ flare constitutes the most serious hazard. We have assumed that such a flare will occur and have calculated the degradation in performance of electronic components caused thereby. Resistors and capacitors are unaffected but transistors are seriously affected. Example: unshielded 50 mc Si and 10 mc Ge transistors will experience gain reduction to 70% of initial; transistors of lower cutoff frequency will experience a proportionately greater reduction. A one gm/cm2 Al shield reduces the damage by a factor of 4 in Si and 5 in Ge transistors.