Educational purposes have been the trigger for CubeSat development. Most of this class of nano-satellites where initially developed as hands-on projects at universities and institutes, mostly being of very simple construction and complexity. However, in the most recent years low cost sensors and mobile technology started to be translated into nano-satellites, and this expanded their possible mission profiles, prompting the attention of companies and government agencies. Today, many tasks that previously where only possible to be developed within a multi-million dollar/euro framework can be accomplished by nano-satellites, at a tiny fraction of their cost. One of the major weaknesses of these devices is the low level of available power onboard, and the lack of efficient state-of-the-art propulsion systems. The present paper provides a throughout discussion on the diverse propulsion technologies used for CubeSat and other micro-satellite systems. If only attitude correction is requested then, present day technologies can be readily used. However, for orbit change or interplanetary nano-spacecraft propulsion, present day technologies are not able to provide the necessary performance under the restricted power budget on-board. New routes are herein proposed for the development of thrusters for nano-satellites and other comparable size spacecrafts.