ABSTRACT
The energy of a photoelectron generated by sunlight is typically only a few eV. Spacecraft charging by photoelectrons is typically to a few positive volts only. If there are other participating currents comparable with the photoelectron current emitted from the sunlit surface of a spacecraft, the current balance of all the comparable currents should be considered for the equilibrium potential ϕ. Therefore, for a conducting spacecraft, the charging level in sunlight is typically a few positive volts only. The surface with high reflectance emits no photoelectrons and therefore charges to a high negative potential in sunlight. At the same time, the other surface, with low reflectance, absorbs the sunlight photon energy and converts it to photoelectron emission. Suppose the first surface gets rid of its electrons received by emitting photoelectrons.
