A spectrometer for the investigation of energetic electrons and ions on board of space vehicles is described. The spectrometer is specially designed for studying fine structure and rapid variation of the fluxes of energetic particles, but can be also used for the conventional on board particle flux monitoring. The instrument has a working energy range of 15-350 keV for electrons and 15 keV-3.2 MeV for protons, an energy resolution of 5 keV, and a time resolution of 31.25 ms. There are 255 various operation modes that can be switched during a space flight by telecommands according to a research schedule.415710713