Many companies, especially in the Aerospace industry, use MBSE to design anddevelop their systems. However, the multitude of MBSE approaches and bestpractices is as broad as the different engineering topics. ESA's systems are composedof many different sources, and the only apparent way of integrating is via theirwritten documentation. It is understood that industry partners would not let go oftheir proven best practices and experience with MBSE.The goal of this study is to identify a way to harmonise different MBSE approaches insuch a way that an ECSS standard can be derived, using Model-based documentationas the main transportation medium.As a first step, different MBSE standards, approaches and tools are evaluatedagainst each other in the context of Space Systems. This will highlight benefits andlimitations of MBSE in Space applications.An investigation about possible tailoring of Space MBSE solutions towards aharmonised ECSS standard will be done. Since each space actor has a differentperception of MBSE, it might be required to develop a transfer mechanism betweendifferent solutions, with which it is possible to integrate and interface differentmodelling paradigms. This tailoring ties into the Unified Modelling Framework, whichcan then be further developed.Finally, the study will provide a way forward in the production of ECSS conformantdocumentation, using as only source the contents of a model: In an MBSE approach,the model is supposed to be superior to hand-written documentation, especially interms of traceability, consistency and structure.