Single Event Upset Measurements of Memory Chips for the Langmuir Probe on STSAT-2 Kwangsun Ryu, Goo-Hwan Shin, Hyung-Myung Kim and Heejoon Kim Satellite Technology Research Center, Korea Advanced Institute of Science and Technology, Daejeon 305-701 Kyungwook Min Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 305-701 (Received 21 September 2007) We have measured the single event e ect (SEE) of candidate memory chips for a Langmuir probe, one of the secondary payloads of STSAT-2 (Science and Technology Satellite-2). The measurements were performed using the cyclotron proton accelerator at Korea Institute of Radiological and Medical Sciences. An ion chamber detector was used for the calibration of the ux of the proton beam. SEU (single event upset) cross-sections for 3 di erent kinds of memory chips were derived according to the incident proton energy. The SEU rate at the STSAT-2 orbit environment was estimated from the SEU cross-section and the modeled particle ux. The program memory chip for the ight model was selected from the candidates. PACS numbers: 61.80.Az, 61.82.Fk, 95.40.+s