SEU RESULTS FROM THE ADVANCED PHOTOVOLTAIC AND ELECTRONICS EXPERIMENTS (APEX) SATELLITE

The APEX satellite, launched in August of 1994, had a solid state data recorder (SSDR) as its onboard data storage system. The recorder cont ained 220 4Mbit X 1 Hitachi DRAMs of which 176 were routinely interrog ated for SEUs and corrected with an EDAC code. Corrections were record ed in the spacecraft housekeeping files and are the basis of this stud y. The SEU rates and spatial locations are compared to insitu particle measurements and to ground test results from devices from the same lo t flown. The results show that properly designed SSDRs are a viable al ternative to conventional tape recording systems for all orbits in nea r-Earth space.