In-flight annealing of displacement damage in GaAs LEDs: a Galileo story

A recent failure of Galileoʹs magnetic recorder was attributed to LED degradation. Annealing the culprit OP133 proved successful: irreplaceable data, taken during the encounter with Jupiterʹs previously unvisited moon Amalthea, was recovered. Annealing test data for both proton and electron displacement damage combined with a simple device temperature model explains some details of the failure and the partial recovery of recorder motor function.