Radiation damage to Hubble has been 4.3 years out of phase with the Solar cycle

Hubble’s CCDs have recorded radiation exposure for over 24 years, showing damage that lags the solar cycle by several years rather than coinciding with sunspot or coronal-mass-ejection peaks. Empirical models of this out-of-phase series recover more than 99.5% of image-quality loss, while physically constrained fits perform significantly worse. The results highlight the distinct low-Earth-orbit radiation environment and the necessity of continuous monitoring to predict degradation of existing and future spacecraft.