Five Year Results from the Engineering Radiation Monitor (ERM) and Solar Cell Monitor on the Van Allen Probes Mission

The Engineering Radiation Monitor (ERM) measures dose, dose rate and charging currents on the Van Allen Probes mission to study the dynamics of Earth\textquoterights Van Allen radiation belts. Over five years, results from this monitor show a variation in dose rates with time, a correlation between the dosimeter and charging current data and a comparison of cumulative dose to pre-launch modeling. Solar cell degradation monitor patches track the decrease in solar array output as displacement damage accumulates. The Solar Cell Monitor shows ~33\% cumulative degradation in maximum power after 5.1 years of the mission. The desire to extend the mission to ~2500 days from 800 days created increased requirements for the ionizing radiation hardness of spacecraft and science instrument electronics. We describe the investigations that insured compliance with these enhanced requirements.