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-satellites, which have been operating for six years in a 1,320 km altitude, 66 degrees inclination orbit, and which are comprised almost entirely of commercial-off-the-shelf(COTS) components. The radiation environment inside both spacecraft is inferred from measurements made by the radiation monitoring payload carried on-board KITSAT-1. Ground-based radiation testing of samples of the COTS devices (including flight spares) using proton and heavy-ion beams, has allowed comparisons to be 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 to 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 carry out its intended mission rapidly and at very low cost.