The space environment hazards are becoming harsh as they affect both the mechanical and electrical properties of the polymer-based reinforced fiber materials in spacecraft. The structure materials changes by Gamma-irradiation often deteriorate the epoxy matrix or the epoxy/nano-composite properties. As a result, the effect of gamma irradiation on the mechanical and electrical properties of the selected materials were evaluated. The mechanical properties and electrical resistivity of nanocomposites were studied by a universal testing system (UTS) and Keithley 2635A System Source Meter respectively. Fourier transform infrared (FTIR) functioned to assess the chemical structural variation due to the gamma-ray exposure. Dynamic Mechanical Analysis (DMA) was conducted to obtain the Tan delta, loss and storage modulus of each sample. The result showed enrichment in both the mechanical properties and the electrical conductivity of Epoxy/MWCNT's nanocomposites.