Impact Technologies has proposed development of an effective prognostic and fault accommodation system for critical DC power systems including PV systems. Overall goal for this program is development of techniques that enable power system fault tolerance based on diagnostic features from the solar cells, power bus, and power transistors. After completion of Phase I efforts towards this goal, Impact has achieved substantial and promising results in several technical areas that provide opportunities for maturing PHM tools. The technical areas covered include: 1) solar cell modeling and characterization, 2) power system monitoring, 3) semiconductor device modeling and aging characterization, and 4) application of the leakage current sensing to DC systems. During Phase II, impact will apply and maturing phase I accomplishments to incorporate and embed effective PHM techniques and fault tolerance for power system reliability and extended operation. Impact also plans development of a prototype low cost dynamic leakage current sensor for solar cell and DC power system application. The long-term implications of a successful completion of this program will provide reliability and health management tools for the state-of-the-art technologies, such as advanced power systems based on solar power generation, contributing directly to NASA's ISHM efforts.