Radiation analysis and mitigation framework for LEO small satellites

In this paper we present a low-cost framework for radiation analysis and mitigation for Low Earth Orbit (LEO) small satellites. Radiation effects of interest are the Total Ionizing Dose (TID), Single Event Effects (SEE) and solar cell degradation. A comprehensive, step-by-step study on these radiation effects are presented using the Galassia nanosatellite and Kent Ridge-1 microsatellite from the National University of Singapore, launched on December 16, 2015 to a Near-Equatorial LEO at 550 km altitude and 15° inclination. Based on this framework, we have evaluated that both Galassia and Kent Ridge-1 would survive the radiation environment, having only accumulated TID of an estimation of 0.023 krad/year and 0.016 krad/year, respectively. Additionally, we have also evaluated (and confirmed on-orbit) that Galassia and Kent Ridge-1 experience SEE. Fault Detection, Isolation and Recovery (FDIR) techniques discussed in this paper managed to help in the continuation of the operation. Lastly, solar cell degradation on both Galassia and Kent Ridge-1 due to radiation is estimated to be negligible.