Two sets of polymer foam blends viz, PF/PMMA/P(C-g-E) and PF/PMMA/ P(PF-g-MMA) and PF/PS/P(C-g-E) and PF/PS/P(PF-g-S) were tested to predict the material performance (see page 162 and following). Mechanical, ther mal, thermophysical and permanence properties were evaluated. The prediction tests of these blend foams indicates that the UV, Vacuum, and thermal stability at 200°C and 10^-6 Torr is in the order: PF/PMMA/P(PF-g-MMA) (175 Sun hrs 5.652 X 10⁹ rads) > PF/PMMA/P(C-g-E) = PF/PS/P(PF-g-S) (140 Sun. hrs, 4.523 x 10⁹ rads) > PF/PS/P(C-g-E) (105 Sun hrs, 3.392 × 10⁹ rads). The higher UV-vacuum-heat stability of the foam is ascribed to the UV-vacuum and ther mal stabilization of thermoplastic and thermosetting polymers respectively. These foam blends are rated as 'C' class space materials which may be used for low-load internal and external and non-structural applications.