The efforts addressed in this thesis refer to assaying the degradations in modern solar cells used in space-borne and/or nuclear environment applications. This study is motivated to address the following: 1. Modeling degradations in Si pn-junction solar cells (devices-under-test or DUTs) under different ionizing radiation dosages 2. Preemptive and predictive testing to determine the aforesaid degradations that decide eventual reliability of the DUTs; and 3. Using electrical overstressing (EOS) to emulate the fluence of ionizing radiation dosage on the DUT. Relevant analytical methods, computational efforts and experimental studies are described. Forward/reverse characteristics as well as ac impedance performance of a set of DUTs under pre- and post- electrical overstressings are evaluated. Change in observed DUT characteristics are correlated to equivalent ionizing-radiation dosages. The results are compiled and cause-effect considerations are discussed. Conclusions are enumerated and inferences are made with direction for future studies. / by George A. Thengum Pallil. / Thesis (M.S.C.S.)--Florida Atlantic University, 2010. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2010. Mode of access: World Wide Web.