SEU rate in 90nm and 180nm of 6T SRAM at NEqO orbit

Razaksat® was a remote sensing satellite which functioned as to acquire the information from the earth surface. razaksat® was launched to low altitudes,around 600km above the earth surface in 2009. although razaksat® was a low altitude satellite but the malfunction of the razaksat® was suspected experienced high rates of anomalies. the main factor of getting high rates of anomalies is due to the razaksat® was exposed to space radiation environment when the satellite passed through the south atlantic region at its neqo trajectory. an investigation was carried out to predict the single event upset (seu) rate for 6t sram,which is located at on-board computer (obc) of the satellite. the results show that the q node in 6t sram is the most sensitive node and this node becomes the main focus in this paper in order to estimate direct ionisation induced seu rates in the worst case scenario. apart from that,the comparison by using 90nm and 180nm of 6t sram are shown whereby with 90nm,around 1083.5 error/bit day is occurred and there is around 4.538 errors/bit day is found by using 180nm of the 6t sram.