The use of a Semantic Grid architecture can ease the deployment of complex applications, in which several organizations are involved and where resources of diverse nature (data and computing elements) are shared. This is the situation in the Space domain, with a strong demand of computational resources inscribed in an extensive and heterogeneous network of facilities and institutions. This paper presents the S-OGSA architecture, defined in the Ontogrid project, as applied into a scenario for the overall monitoring and data analysis in a Satellite Mission currently in nominal operations. Flexibility, scalability, interoperability and use of a common framework for data sharing are the main advantages of a Semantic Grid implementation in Complex and dataintensive systems.