Résumé : Based on the User Support Organization definition concept, this paper describes how user support for the precursor missions could be implemented. A survey of the facilities to be included in the Spacelab E1 and the EURECA 2 missions has been performed. Additionally, an overview of the national user support activities in Europe is given. It is assumed that this infrastructure can be applied for precursor mission support, as well. On the basis of the results of these two surveys, an exercise was executed to map the various support functions to be performed by the available Utilization Centres. In this work, the Facility Responsible Centre and Experiment Support Centre status was assigned to various centres. The results of the mapping exercise are presented in this paper. © 1993.