Observed radiation-induced degradation of commercial-off-the-shelf (COTS) devices operating in low-earth orbit

Observations of single-event effects (SEEs) and total-dose degradation are presented for the data-handling system of the S80/T and KITSAT-1 micro-sate llites, which have been operating for six years in a 1,320 km altitude, 66 degrees inclination orbit, and which are comprised almost entirely of comme rcial-off-the-shelf(COTS) components. The radiation environment inside both spacecraft is inferred from measureme nts made by the radiation monitoring payload carried on-board KITSAT-1. Ground-based radiation testing of samples of the COTS devices (including fl ight spares) using proton and heavy-ion beams, has allowed comparisons to b e made between the observed performance of the devices under this radiation environment, and predictions made using standard models. The conclusion is that, whilst the accumulated radiation damage is likely t o cause the spacecraft to fail in the near future, the use of COTS devices coupled with a not-tooconservative design, has enabled the satellite to car ry out its intended mission rapidly and at very low cost.