At this point, the calibration and performance verification (PV) phase will commence. The PV phase is intended to obtain in-flight characterisation of all instruments e.g. in terms of stability, sensitivity, resolution, timing and other calibration parameters. It includes the validation of the instrument observing modes and the calibration and data processing of the resulting data. To achieve this, a schedule of astronomical observations and internal calibrations, defined and iterated pre-launch covering a nominal period of 2 months will be executed using normal observatory procedures. This schedule will be based upon an agreed in-orbit calibration plan generated jointly by the ICCs and the HSC. The plan contains a description of all planned calibration activities and associated calibration sources (internal and astronomical) required to characterise fully each instrument.