OBSERVATION AND PREDICTION OF SEU IN HITACHI SRAMS IN LOW-ALTITUDE POLAR ORBITS

In-orbit SEU data from three microsatellites are separated into Galact ic Cosmic Ray (GCR), South Atlantic Anomaly (SAA) and solar flare upse ts. Heavy ion and proton testing of the same devices are reported and predictions using LET-dependent ion cross sections and a 2-parameter f it to proton cross section data are compared with in-flight data. SEU trends in memory devices from a single manufacturer, from 16 K-bit to 4 M-bit, are identified.