  The study is devoted to a problem of electron-induced contaminant to X-ray
and gamma-ray astrophysical measurements on board low-orbiting satellites. We
analyzed enhancements of electron fluxes in energy range 100 - 300 keV observed
at equatorial and low latitudes by a fleet of NOAA/POES low-orbiting satellites
over the time period from 2003 to 2005. It was found that 100-300 keV electron
fluxes in the forbidden zone below the inner radiation belt enhanced by several
orders of magnitude during geomagnetic storms and/or under strong compressions
of the magnetosphere. The enhancements are related to high substorm activity
and occurred at any local time. Intense fluxes of the energetic electrons in
the forbidden zone can be considered as an essential contaminant to X-ray and
gamma-ray measurements at low-latitude and low-altitude orbits.
