RBC Technologies has significanly improved the cycle life and wet life of silver/zinc battery technology through novel separator and anode formulations. This advanced silver/zinc technology may be further developed to work reliably in the low temperature and pressure environment of the upper atmosphere. The objective of the proposed program is to develop sealed spirally wound cylindrical silver cells and demonstrate their capability to deliver high specific energy and specific power at temperatures to -30C. This will be accomplished by the innovation of coated silver cathode and zinc anode formulations suitable for incorporation in high performance wound sealed cells with low freezing point electrolytes. In Phase I RBC will work with Moltech Power Systems to design and assemble test cells and assess energy, power and fade characteristics. In Phase II, RBC would build upon these results to design and assemble complete cells and batteries that would meet or exceed a modular battery specification for NASA earth science missions.