Radiation environment monitors (REMs) on-board the STRV-1b spacecraft in geostationary transfer orbit (GTO) and externally on Mir have returned valuable results over the last few years. STRV data show the great variability of the electron radiation belt and a stable proton belt feature. In this paper, a detailed assessment is made of the flux values derived from the REM on STRV and particularly how they compare with the AE-8 and CRRESELE electron radiation-belt models. To compare with CRRESELE, the activity index Ap/sub 15/ is used and the behavior of this index as a parameter is assessed. GOES data are used to aid this assessment.