In recent years, there has been a large increase in the number of small satellites being designed, built and launched. Due to resource constraints, these spacecraft have not generally included any propulsion capability, and this has severely limited mission capabilities and lifetime. To enhance their performances, next generation of small spacecraft will require extremely miniaturized, highly integrated propulsion systems capable to meet stringent mass, volume and power constraints. Two of the most promising technologies to achieve these goals are Electric Propulsion (EP) systems and Micro Electro Mechanical Systems (MEMS). The study identifies a wide variety of mission scenarios, satellites and EP technologies which could benefit from the use of MEMS leading to a selection of one propulsion technology that seems the most promising: the colloid thruster propulsion system. For this technology the requirements are identified and then a preliminary MEMS based EP system design is established. Modularity is very important to enable the same design to be used over and over again and critical subsystem units, such as the high voltage power and control electronics, have also to be developed for the integration in the modular concepts. Two basic design concepts have been investigated to cover the wide range of applications and missions scenario stated within this study and they are presented in this paper.