Software based memory correction for a miniature satellite in low-Earth orbit

Sammanfattning: The harsh radiation environment of space is known to cause bit flips in computer memory. The conventional way to combat this is through error detection and correction (EDAC) circuitry, but for low-budget space missions software EDAC can be used. One such mission is the KTH project Miniature Student Satellite (MIST), which aims to send a 3U CubeSat into low-Earth orbit. To ensure a high level of data reliability on board MIST, this thesis investigates the performance of different types of EDAC algorithms. First, a prediction of the bit flip susceptibility of DRAM memory in the planned trajectory is made. After that, data reliability models of Hamming and Reed-Solomon (RS) codes are proposed, and their respective running times on the MIST onboard computer are approximated. Finally, the performance of the different codes is discussed with regards to data reliability, memory overhead, and CPU usage. The findings of this thesis suggest that using an EDAC algorithm would greatly increase the data reliability. Among the codes investigated, three good candidates are RS(28,24), RS(196,192) and RS(255,251), depending on how much memory overhead can be accepted.