Busek proposes to prove the feasibility of a Mg Hall effect thruster system that would open the door for In-Situ Resource Utilization (ISRU) based solar system exploration. Elemental magnesium has favorable thermophysical properties and is very easy to ionize. The estimated specific impulse for a high efficiency magnesium Hall thruster operating off of a standard 400 V power processing unit is 5000 s. Efficiencies >50% will be possible. Although the vapor pressure of Mg is relatively low, it is believed that spacecraft interactions can be managed through the implementation of a simple plume shield. Moreover, magnesium is found abundantly in the regolith of Mars and the Moon, from which it can be readily extracted. In Phase I, we will prove the concept's feasibility through four technical tasks. In the first task, the overall architecture of a Mg Hall thruster system will be established and subsystem requirements will be identified. In the second task, Busek will integrate an magnesium vapor propellant Hall thruster with a wire feed system. In the third task, the integrated system will be tested in Busek facilities. In the fourth task, the Applied Research Laboratory (ARL) at Penn State University will develop a powder feed system capable of fueling both medium and high power thrusters. A fully integrated system sized for NASA needs will be developed and characterized in Phase II.