Yu.A. Valetov, А.А. Gusev, E.V. Ilyin, V.V. Karpin, E.S. Kolodochkin, A.V. Rybakova, V.S. Chudnovskiy

Flows of electrons in the radiation belts of the Earth lead to electrization of the optical surfaces of onboard equipment. Electrical volume disruption in glasses of mark К-208 occurs when the flows of electrons with energies of 5-15 MeV are forming branched discharge channels; as a result, defects are formed inside the glasses, and optics degradation is observed. Studying of flows of electrons with energies of 5-15 MeV has not been made previously in orbits of «GLONASS» spacecraft. The purpose of the work - an estimation of additional dose loads during solar flashouts, drawn from the results of measurement by the onboard equipment «BAL-M», and an estimation of fluence of flows of electrons from registrations by the onboard equipment «BAL-K». Calculations of additional dose loads, caused by solar flashouts from 2004 to April 2012, drawn from the results of registering of proton flows by the onboard equipment «BAL-M» are given in this work. Features of flows and fluence values of the electrons registered by the onboard equipment «BAL-K» are studied, the estimation of optical systems degradation in the onboard equipment is given. The results of calculation are compared with the results of space flight experiment for studying of major-size optical devices degradation on the spacecraft № 735. The gained results are now included in the development of onboard imaging equipment for the new generation «BAL-K2».