A spacecraft structure has a capacitance of the order of the capacitance of a sphere of equivalent radius R, i.e.
The characteristic charging time is
It is of the order of 10-3 seconds for kV charging for J=1 nA cm-2.
The capacitance of a dielectric patch with area A and thickness t is given by
The time constant for differential charging is therefore:
It is of the order of 1 second for kV differential charging of a patch of thickness 1 mm under a current density of J=1 nA cm-2.
High level charging environment typically lasts of the order of 1 hour at GEO and of the order of 1 minute at PEO.