KITSAT-1, launched in 1992, passes through Inner Van Allen radiation belt in which high energy protons cause Single Event Upsets(SEUs) in the main memory of KITSAT-1 OBC(On-Board Computer)186. Present thesis estimates the SEU threshold energy from KITSAT-1 data using AP-8 model of NASA/NSSDC. Shielding effect by the spacecraft body has been taken into account to estimate the proton fluxes at the position of OBC186, and the SEUs calculated from this model are compared with the actual count rates from KITSAT-1 using the Chi-square method. SEUs recorded during the high solar activity has been removed to avoid the spurious result.
A correction is made to convert the count rates along the orbital path into the count rates on the geographical position. The result shows that the SEU threshold energy of main memory of KITSAT-1 OBC(On-Board Computer)186 is estimated to be about 210MeV.
