Cosmic radiation effects on avionics

The earth is bombarded by a nearly isotropic flux of energetic charged part icles called cosmic rays which interact with air nuclei to generate a casca de of secondary particles building up to a maximum intensity at 60 000 feet . At normal cruising altitudes, the radiation is still several hundred time s the ground level intensity. These particles are sufficiently energetic an d ionising that they can deposit enough charge in a smalt volume of semicon ductor to change the state of a memory cell, while certain devices can be t riggered into a state of high current drain, leading to burn-out and hardwa re failure. These deleterious interactions of individual particles are refe rred to as single event effects. The authors have flown Cosmic Radiation Ef fects detectors in a variety of spacecraft and aircraft and illustrative re sults will be presented together with a review of published instances of su ch phenomena in flight systems. In the future there is likely to be increas ed susceptibility due to growing reliance on high performance computers usi ng smaller devices operated at lower voltages and flying at higher altitude s. The influence of cosmic rays will have to be properly considered in the assessment of reliability. (C) 1999 Published by Elsevier Science B.V.