The International Space Station (ISS) is the largest space programme that has ever been undertaken on the basis of international cooperation (United States, Russia, Japan, Canada and Europe). Within the framework of this programme, Europe is in charge of the Columbus Module. More particularly, the Belgian User Support and Operation Centre will be the Facility Responsible Centre (FRC) for the SOLAR Observatory and the Facility Support Centre (FSC) for the Proteins Crystallization Diagnostic Facility (PCDF), which will be part of the European Drawer Rack (EDR). The past two years, the B-USOC, as part of the European Space Agency (ESA) Decentralized Ground Segment Infrastructure, managed telescience and operational aspects in four space missions: the OdISSea mission to the International Space Station by using a Russian Soyuz Taxi-flight, performed by Belgium (Federal Science Policy Office) with the support of ESA (October-November 2002), the 15 days STS-107 Shuttle mission (January 2003), the CERVANTES mission to the ISS, a Russian Soyuz Taxi-flight performed by Spain (October 2003), and a 30 days ESA-NASA mission onboard the ISS (February-March 2004). In those missions, B-USOC implemented and maintained, in collaboration with ESA and NASA, a dedicated ground segment for operations in order to link together all centres involved via international communication networks, and to manage several types of data interfaces (Telemetry, Command, Video, and Voice). B-USOC also collected all ground segment requirements from the Belgian users community and allowed Belgian User Home Bases to connect to the missions ground infrastructure. The present paper gives details of the ground segment implemented for the above-mentioned missions and emphasizes the specific role of the B-USOC and its interactions with the other partners’ operation centres. In conclusion, the future operational activities of the B-USOC and its involvement in the European Columbus project will be described.