This paper reports on a case study investigating the interest of formal data modeling approaches on functional parts and solve difficulties coming from lack of formalism in the description and handling of data analysis of space software data and their classifiation into families (section 2) and the elaboration of an A.S.N.1 data model for a case study representative of these data families (section 3). The second part illustrates two important outcome of such formal data models : the capability to automatically generate " Interface Control Documents", the contractual documents describing software interfaces and data (section 4) and automatically generate the needed interfacing code with the appropriate format encoders and decoders (section 5)