The charging of the space vehicles and their elements leads to failures of an electric equipment. Especially sharply given problem is shown on geostationary satellites which are in a high orbit long time. The charging of S/C occurs as a result of influence on its surface of some the factors, in particular surrounding space plasma and solar electromagnetic radiation. The sign and size of an electric charge formed on surface of S/C depend on a activity parity of the processes providing receipt on a surface and a drain from it of positive and negative charged particles, and also from characteristics of constructional materials and features of S/C geometry. For studying charging process, its influences on working capacity of the electronic equipment, on S/C "Foton-M" #2, with parameters: height of an orbit - 300 km, duration of flight - 14 days, have been established 4 superficial gauges and 1 remote charging sensor. This sensors together with the equipment of processing of the information allow to measure a stream of the charged particles on surface of S/C and own charge at all stages of flight. Preliminary mathematical modeling of charge process of S/C has allowed to choose key parameters of charging sensors. The values of potentials received as a result of experiment in general coincide with theoretical estimations, but allow to specify the mechanism of formation of a superficial charge of S/C. Preliminary processing of the received data has shown, that the maximal potential does not exceed 7 Volts.