G_RVS zero-point plotted against OBMT. The blue points represent the ZP_CaU estimates (from Eq. (3)) every 30 h for the CCD in row 6, strip 2, and FoV 2 (see Fig. 1 of Sartoretti et al. 2018) over the DR3 observing period. The black line is the calibration model for ZP(t). The arrows indicate break points between which the calibration model is fitted. The break points correspond to the following events: decontaminations (red arrows), refocus (blue arrows), and discontinuities in the astrometric solution (grey arrows). At the beginning of the mission, the Gaia optics suffered from heavy water ice contamination, which resulted in rapid degradation of the ZP. The first two decontamination events, at OBMT 1317 and 2330, produced a significant improvement in ZP. After the second decontamination event, the ZP stabilised, and the third decontamination event, which is also the last one performed on Gaia, resulted in no significant improvement. The other events have no significant effect on the ZP.