Electron and Ion Spectrometer (EIS) onboard Planet-B will measure the energy flux of high enegy particles such as electrons, photons, helium ions and oxygen ions ,in the range of 40 keV to 500 keV per charge. An interaction of the solar wind with the upper atmosphere of Mars produces energetic electrons and ions of a few hundreds of eV to a tens of keV. The EIS will measure these particles and contribute to the understanding of the acceleration mechanism.