Investigation of the onboard instruments photocurrent during solar maximum

The characteristics of the photocurrent emitted by the onboard space plasma instruments of the satellite 'Interkosmos Bulgaria - 1300' were investigated. A massive search was made in the existing data base for the interesting registered events during the full satellite life. Precision solar spectrum data for the present solar minimum are applied to the possible photocurrent zones for the different materials used in the space instrumentation. Special attention was given to the 21st cycle solar maximum. All interesting orbits were found close to the peak of the solar activity of this cycle. The data processing results are shown in the chart. (authors)