This thesis was produced at Cranfield University, with support from EADS Astrium who introduced the base requirements for the study. The subject to be researched was the possibility of using Cubesats for producing viable Earth Observation missions when they would be used in some constellation configuration. The project involved surveying nanosat / Cubesat constellation markets and concepts (e.g. real-time data) for Earth Observation, using new / enabling technologies (i.e. deployable membranes, quad junction cells, miniature instruments). The project also contributes to the Cubesat projects by providing a roadmap of possible future missions enabled by advanced Cubesats. The study concluded by selecting a present day possible mission which could be developed by using COTS components and space-proved instruments and some missions which could be developed in the near future using other new technologies yet to be made available for space applications. Some simulations of the possible missions were performed in order to determine the best configurations and results are presented in the discussion and conclusion chapters.