Localization of Onboard Processor Upsets in the Magnetosphere and Their Automatic Correction on the lnterball-2 (Auroral Probe) Satellite

The scientific data acquisition system (SSNI) has been operating onboard the Tail Probe and Auroral Probe satellites of the INTERBALL project for more than two years. In the two years of operation on the Auroral Probe satellite, the system has received about 20 gigabytes of scientific and service information from instruments and transmitted them to the Earth. The authors of the SSNI system managed to exclude data losses connected with the effect of radiation by changing the onboard program of the system microprocessor during flight. After that, SSNI recorded and automatically corrected about 400 single event upsets (SEU) in the RAM. The system recorded the precise time of each upset appearance, which allowed spacecraft locations to be determined at these instants. In this paper, the results of the analysis of the spatial and temporal distribution of SEU are presented, and possible reasons for the upsets are discussed. Most SEU appeared when the spacecraft was in the region of the Earthʹs inner radiation belt and, judging from their localization, can be explained by the influence of protons with an energy of 50 MeV and above, penetrating the SSNI electronic unit. Moreover, a noticeable number of upsets are localized in the region of high magnetic latitudes, where no high-energy protons are observed, so that these SEU are likely caused by other reasons. In this paper, possible variants of reducing the SEU effect in the process of designing onboard and other computer systems operating under conditions of irradiation by penetrating particles, are also discussed.