Since 2008, the MicroThrust (MT) consortium consisting of EPFL, Nanospace, QMUL, SystematIC, and TNO has been working on the development of a MEMS based electric propulsion system. Since 2010, the work has been performed as part of the European Union’s FP7 programme with the goal to design, build and test an engineering model of such a system. The engineering model shall show that this propulsion system can fit in a nano-satellite in terms of mass, volume and power consumption, while giving the satellite a very large ∆V capability (up to 5 km/s). These requirements can only be met by extreme miniaturization and integration of all components. As a first step towards the engineering model, a laboratory breadboard model is currently under development. This paper starts with an analysis of a range of different mission scenarios that the MT could perform, to make sure that the mission requirements are clearly understood. It then describes the working principles and some of the design choices behind the different components of the breadboard. The project is now well underway, and some of the breadboard components are starting to take shape. Testing of the complete breadboard system is scheduled for 2013.