NASA will return to the IIS by 2014 and the moon by 2020. To accomplish these missions, NASA will exploit to the maximum degree possible the Apollo architecture and especially the lessons learned and technological advances that have occurred over the intervening 40 years in building robust, cost effective, efficient, and, partly reusable launch, lander, explorer, and resupply vehicles. In support of this effort, Technology Assessment & Transfer (TA&T) proposes to develop a magnesium metal matrix composite (MMC) for use as aerospace structural members. This material exhibits three times the specific stiffness of the best aluminum-lithium alloys and two times that of PMCs. TA&T will demonstrate the feasibility and practicality of a low temperature method for achieving high loading of ceramic particles in a magnesium matrix that will enable a cast or extruded structural material of non-uniform cross-section exhibiting the unusual combination of light weight, high specific stiffness and strength, radiation shielding, and low cost. The MMC will be protected from corrosion by a unique thin film coating designed specifically to prevent corrosion of aluminum and magnesium alloys.